peerj_json_files/PeerJ_Json_122.json

{
    "v1_Abstract": "How behavioral patterns are related to niche partitioning is an important question in understanding how closely related species within ecological communities function. Behavioral niche partitioning associated with thermoregulation is well documented in tiger beetles as a group. Co-occurring species of salt flat tiger beetles have adapted many thermoregulatory behaviors to cope with this harsh ecosystem. On first examination these beetles appear to occur in overlapping microhabitats and therefore compete for resources. To determine if behavioral niche partitioning is allowing multiple species to occur within the same harsh salt flat ecosystem we observed Cicindela nevadica lincolniana, Cicindela circumpicta, Cicindela fulgida, and Cicindela togata between 8:00 hours and 21:00 hours and recorded all behaviors related to thermoregulation using a digital voice recorder. Results of this study strongly indicate that competition among these species for resources has been reduced by the adaptation of different thermoregulatory behaviors such as spending time in shallow water, avoiding the sun during the hottest parts of the day, and by positioning their body against or away from the soil. The endangered C. n. lincolniana appears to rely most heavily on the shallow water of seeps for their diurnal foraging behavior (potentially limiting their foraging habitat), but with the advantage of allowing foraging during the hottest times of the day when potential competitors are less frequent. Ironically, this association also may help explain C. n. lincolniana\u2018s susceptibility to extinction: beyond the loss of saline wetlands generally, limited seeps and pools even within remaining saline habitat may represent a further habitat limitation within an already limited",
    "v1_col_introduction": "introduction  : Competition is one of the main forces driving niche partitioning and, consequently, speciation. Interspecific competition may lead to segregation among or within habitats followed by adaptations to different microhabitats (Schultz & Hadley, 1987). Ultimately, adaptation through selection is genetic but the phenotypic expression of selection may take many forms. Although we commonly think of physiological and morphological changes as products of selection through niche partitioning, variation in the behavior of sympatric species also can be a mechanism for niche partitioning. Harsh environments, where the biota is reduced and physiological adaptation is essential for survival, present ideal laboratories for examining the interplay of adaptation and competition. In such systems, the strong selection pressure associated with the physical environment provides a stage upon which interspecific competition plays. Saline wetlands, and their associated salt flats are one such harsh environment. The saline wetlands of eastern Nebraska are home to a unique cast of adapted organisms. Along with saline requirements in these organisms\u2019 life histories, many also are adapted to tolerate the harsh, desert-like environment typically associated with salt flats during the summer months (Farrar & Gersib, 1991). Within this environment exists a large assemblage of congeneric, sympatric tiger beetle species, including the endangered Cicindela nevadica lincolniana (Willis, 1967; Spomer & Higley, 1993; Spomer, Higley, & Hoback, 1997). Because of the uniqueness of this environment and the endangered status of one of these beetle species much attention has been given to this group of tiger beetles. Behaviors that serve to partition resources and reduce physiological stress have been examined for many species of tiger beetles, Cicindelidae, but much remains to be discovered about the diversity and functions of tiger beetle behavior (Pearson & Mury, 1979; Pearson 1980; Pearson & Stemberger, 1980; Pearson & Knisley, 1985; Ganeshaiah & Belavadi, 1986; Schultz & Hadley, 1987; Hoback et al., 2000; Hoback, Higley, & Stanley et al., 2001; Romey & Knisley, 2002). Past and current research supports the theory that these tiger beetles are using oviposition 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66\nPeerJ reviewing PDF | (v2013:07:669:1:0:NEW 24 Aug 2013)\nR ev ie w in g M an\nus cr ip t\nas a mechanism for niche partitioning (Hoback et al., 2000; Hoback, Higley, & Stanley, 2001; Allgeier, 2005). Tiger beetle larvae do not move more than a few cm from where their eggs are originally deposited by the female. Among three salt marsh tiger beetle species (C. n. lincolniana, C. circumpicta, and C. togata) we observed oviposition differences based on soil salinity (Algeier 2006; Brosius 2010). This unique life history trait, along with the larval dependence on limited prey resources for proper development (Mury Meyer, 1987), emphasizes the importance of the location chosen for oviposition. Prey also are essential to adult female fecundity. The amount of prey consumed by adult females is directly tied to their ability to lay greater numbers of eggs (Pearson & Knisley, 1985). The ability to lay more eggs can be important to the success of individual populations given high mortality in the larval stages. For example, Shelford (1913) documented the mortality of some populations of Cicindela scutellaris to be as high as 80% due to the parasitoid Anthrax sp., and Knisley and Shultz (1997) documented a mortality rate upwards around 63% from tiphiid wasps. Because females must gain enough caloric resources for egg production and development, it is likely that adult tiger beetle assemblages have evolved behaviors to reduce interspecific competition as adults. In particular, beyond direct competition for prey (e.g., Hoback et al., 2001), competition may be mediated through partitioning of foraging habitats: spatially, seasonally, or temporally. In this partitioning, temperature tolerance to the foraging habitat may play a key role. There is a long history of thermoregulation studies that focus on tiger beetles and that link thermoregulation behaviors to resource partitioning (Dreisig, 1980; Dreisig, 1981; Dreisig, 1984; Dreisig, 1985; Morgan, 1985; Pearson & Lederhouse, 1987; Schultz & Hadley, 1987; Schultz, Quinlan, & Hadley, 1991; Schultz, 1998; Hoback, Higley, & Stanley, 2001; Romey & Knisley, 2002). Many tiger beetles are found in environments where temperatures are capable of exceeding 60\u00b0C, a lethal temperature for most insect species (Hadley 1994). From these studies it is clear that Cicindela are capable of regulating their body temperatures by changing their body 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92\nPeerJ reviewing PDF | (v2013:07:669:1:0:NEW 24 Aug 2013)\nR ev ie w in g M an\nus cr ip t\norientation and shuttling between microclimates. Adult tiger beetles spend a high percentage of their day balancing foraging behavior with thermoregulatory behavior. Pearson and Stemberger (1980) determined that the gain of one hour of additional foraging could increase the biomass of ingested prey by as much as 20%. This increase in prey would translate into an increase in egg production for adult females. Physiological character divergence in species\u2019 ability to cope with temperatures could be a mechanism to reduce intraguild predation. Differences in heat tolerances between species is a likely mechanism to reduce competition, however, a close examination of lethal maximum temperature of 13 tiger beetle species near Willcox, Arizona, USA revealed very few differences between upper heat tolerances among species (Pearson & Lederhouse 1987). Out of the 13 species examined in this study only two were found to be significantly different and the difference was less than one degree from the overall mean of 48.1\u00b0 C. Hoback, Higley, & Stanley (2001) determined the lethal maximum temperature for two species of tiger beetles (Cicindela circumpicta and Cicindela togata) within the complex of co-occurring species in the eastern saline wetlands of Nebraska and found no differences between species, with results similar to values observed by Pearson and Lederhouse (1987) with different Cicindela species. While tiger beetle species may have some variation in their ability to cope with different degrees of humidity and temperature (Pearson & Lederhouse, 1987; Schultz & Hadley, 1987; Schultz, Quinlan, & Hadley, 1991) physiological differences cannot account for all behavioral differences observed in the field. To determine the evolutionary cause for such differences, Hoback, Higley, and Stanley (2001) investigated lethal high temperatures, prey base, prey size, mobility, and the effect of direct predation of C. togata by C. circumpicta. Laboratory studies that investigated feeding behavior of C. togata in both the absence and presence (separated by a clear pane of glass) of C. circumpicta indicated that C. togata feeding behavior was negatively affected by the presence of 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117\nPeerJ reviewing PDF | (v2013:07:669:1:0:NEW 24 Aug 2013)\nR ev ie w in g M an\nus cr ip t\nC. circumpicta. These results coupled with field observations strongly indicated that intra-guild predation was possible among salt marsh tiger beetles. In the case of C. n. lincolniana and its co-occurring Cicindela species it is likely that similar evolutionary forces are at work as seen in earlier studies are at work. Past research strongly suggests that behaviors associated with the reduction of predation, thermoregulation, foraging, and predator avoidance may reduce competition among sympatric, adult tiger beetles (Pearson & Mury, 1979; Schultz & Hadley, 1987; Pearson & Juliano, 1991; Romey & Knisley, 2002). Consequently, we examined diurnal behavior of foraging salt marsh Cicindela species, with particular focus on potential differences in thermoregulatory behaviors. In particular, given the endangered species status of C. n. lincolniana, we were interested in identifying any unique adaptations that might contribute to population declines different from the other salt marsh tiger beetle species. Methods and Materials\nDuring the summer of 2007 initial observations were made of three species of saline\nadapted tiger beetles: C. circumpicta, C. togata, and, C. n. lincolniana at the Arbor Lake Complex, Lincoln, NE. From these initial observations it appeared that these tiger beetles exhibit a large variety of behaviors and use a wide range of microhabitats. Behaviors associated with thermoregulation were of particular interest. Based on the 2007 data, an ethogram or catalogue of discrete behaviors was developed. Observations were classified specifically as states, events, and behaviors. \u201cStates\u201d described physical aspects of the environments, here, temperature, light, and substrate. Temperature included measures of soil-surface temperature, 1cm above the soil (comparable to tiger beetle body height), and ambient (1m) air temperatures. Light indicated if the subject was standing in the sun or shade. Substrate indicated if the subject was on dry soil, mud, or shallow water (typically on water near seeps or on algal mats along stream margins). \u201cBehaviors\u201d included running, stilting, basking, and standing. Stilting occurs when the tiger beetle holds itself up off of the substrate with its front two legs extended straight downward.\n118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144\nPeerJ reviewing PDF | (v2013:07:669:1:0:NEW 24 Aug 2013)\nR ev ie w in g M an\nus cr ip t\nOften the beetles appear to be standing at a 45\u00b0 angle from the vertical. Stilting occurs during the hottest time of day in an effort to reduce surface area and keep bodies away from the hot soil surface (Pearson & Vogler, 2001). Basking occurs when the tiger beetle presses its body up to the substrate in an effort to warm its body in the early morning hours (Pearson & Vogler, 2001). \u201cEvents\u201d were recorded when individuals exhibited a behavior that had no measurable time duration. Events included mandible dipping (dipping mandibles into the substrate beetles were are standing on), wing pumping (a quick opening and closing of their elytra), flight (this event had a measurable time duration but we almost always lost track of the individual), and abdomen dipping (the individual would dip its abdomen into the water by doing what appeared to be a quick pushup). Behaviors of four co-occurring species of tiger beetles were examined on 20 June 2008, 30 June 2008, 7 July 2008, 23 June 2009, and 2 July 2009. Dates were chosen based on the predicted weather. We chose days that were predicted to have average or above average temperature with no precipitation. Species included C. circumpicta and C. togata, C. n. lincolniana, and the spring-fall species C. fulgida (which occasionally occurred in early summer). Behavior, states, and events were recorded using digital voice recorders and later transcribed using the program JWatcherTM (Version 1.0). One recording was made for each hour in the field. For each hour, three or four observers were randomly assigned a species to observe. Recordings were made from the first individual of that species the observer could locate using close-focus binoculars. At the start of each recording the observer noted the date, time, species, and, observer name. The observer watched one individual as long as they could in a 30 minute period. If recordings were less than 10 minutes in length the observer recorded a second individual of the same species for that hour. On the rare occasion that no species of that individual could be found (after at least 15 minutes of looking) the observer selected the first tiger beetle that they could find for recording observations. Along with these behaviors hourly 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170\nPeerJ reviewing PDF | (v2013:07:669:1:0:NEW 24 Aug 2013)\nR ev ie w in g M an\nus cr ip t\ntemperatures were recorded. The surface temperature was taken from the area near where the recordings were being made. Temperature measurements were taken at 1 meter and 1 cm elevation from the same location. Because tiger beetle\u2019s bodies are approximately 1 cm above the soil surface, we used 1 cm measurement to reflect the temperatures being experienced by the beetles. The data were entered into the program JWatcher. For each block of time, we averaged time spent exhibiting individual behaviors (basking, running, standing, and stilting), time spent in sun or shade, and time spent on type of substrate (mud, dry soil, and water). Because times that each individual was watched varied, we converted the time spent to percentages for species comparisons. Events were averaged by hour by species. Analysis. Statistical differences were examined by using non-parametric approaches, because data were not normally distributed and could not be transformed to meet normality requirements. We used non-parametric procedures in GraphPad InStat (version 3.10 for Windows, GraphPad Software, San Diego California USA, www.graphpad.com) for analyses. These procedures included Mann-Whitney tests or non-parametric ANOVA with Kruskal-Wallis Test (corrected for ties) for overall significance, and Dunn\u2019s Multiple Comparison for separating species where the Kurskal- Wallis indicated a significant overall effect. The logic of statistical choices and limitations follow that of Motulky (2009). Responses to state and behavior variables were analyzed by determining the mean time in a state for two periods: morning (8:00-11:00) and afternoon (11:00-21:00). The decision to subdivide the day into these two periods was made a priori based on the expectation of substantial temperature and behavioral differences at these times of day (based on published research and our own previous observations). Events were analyzed based on mean counts per day (i.e., the number of occurrences of each event). States, behaviors, and events were analyzed across species and within species. For analysis purposes the combination of day and different individuals within a species represents our replications. Additionally, randomly assigning 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196\nPeerJ reviewing PDF | (v2013:07:669:1:0:NEW 24 Aug 2013)\nR ev ie w in g M an\nus cr ip t\ndifferent observers to record behaviors for different species each hour was used to minimize any potential bias among observers recording behaviors. Results\nStates. State variables of association with temperature, light, and substrate differed with\ntime of day and among species (Figures 1-4). Temperatures increased until 15:00 in all measurements (Figure 1). As a result of the absorption of solar radiation, soil temperature became higher than ambient and 1 cm air temperatures after 11:00. At 08:00 the surface temperature was more than 1\u00b0C cooler than 1 cm above the surface and ambient temperature. By 15:00 the surface temperature was 7.9\u00b0C higher than at 1 cm above the surface. At 08:00 there was almost no difference between ambient temperature and 1 cm above the soil surface (0.12\u00b0C). At 16:00 hours the difference rose to 1.9\u00b0C. Temperatures dropped dramatically between 20:00 and 21:00. At 1 cm above the salt flat surface, temperatures dropped 5.4\u00b0C. Time spent in the sun was directly linked to the time of day and, therefore, temperature. For all species time spent in the sun was significantly higher in the morning (08:00-11:00) when the salt flat temperatures were the coolest (Figure 2, Table 1). As temperatures rose the amount of time spent in the shade increased for all species (Figure 2). Significant differences in percentages of time spent in the sun were found between species. Cicindela nevadica lincolniana spent the most time in the sun throughout the day (77.1% of their total time) (Figure 2, Table 1). Cicindela togata spent the most amount of time on dry soils (Figure 3, Table 2). Cicindela nevadica lincolniana spent significantly more time standing on the damp surfaces and in the shallow water of the seeps than the other species observed (Figure 3, Table 2). Both C. circumpicta and C. fulgida spent the majority of their time on damp substrate as opposed to dry soil (Figures 3a & 3c, Table 2). Cicindela circumpicta spent more time on dry substrate when temperatures rose in the late afternoon (Figure 3a, Table 2). Cicindela fulgida spent the most amount of their time on damp substrate (60.1% total) and time spent on damp substrate increased with temperature (Figure 3c, Table 3).\n197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222\nPeerJ reviewing PDF | (v2013:07:669:1:0:NEW 24 Aug 2013)\nR ev ie w in g M an\nus cr ip t\nAnother important difference in habitat use was indicated by associations with standing in\nwater (at margins of seeps and streams). Of the species observed, during the hottest parts of the day C. n. lincolniana spent over a third of the time in water, while other species spent little or no time in water (Figure 3, Table 4). Behaviors. All four species of tiger beetle spent a large portion of their time alternating between standing and running (Figure 4). This reflects typical tiger beetle foraging behavior where they run in short bursts or stand watching for prey (Pearson & Juliano, 1991). Cicindela togata had the largest shift between running and standing in the middle of the day (Figure 4d). Basking was almost always associated with morning hours (before 11:00) and evening hours (after 16:00), with more than three times more basking in the morning than later. Across species, basking occurred 15.5% of the time before 11:00 versus 5.1% of time after 11:00 (Mann-Whitney U = 13.86, P < 0.0001). This difference lined up with the coolest hours of the day. Stilting was almost completely associated with the middle parts of the day for all four species. Cicindela circumpicta spent more time basking in the early hours (Figure 4a). Events. The total events per hour were averaged over the entire day for all four species (Table 5). Cicindela nevadica lincolniana was the only species to display abdomen dipping into water (Table 5). Similarly, C. n. lincolniana averaged 78.05 mandible dips per hour, which was far greater than C. circumpicta which was the next highest at 5.44 mandible dips per hour. Cicindela togata averaged 0.88 flights per hour, which was greater than C. fulgida which was the next highest at 0.51 flights per hour. Cicindela togata appeared to make many short flights during the 8:00 time block but short flights seemed to have no other significant correlation to time of day for any other tiger beetle species (Figure 5). Wing pumping occurred in greater frequency in C. n. lincolniana earlier in the day but appeared to occur with greater frequency later in the day for C. circumpicta (Figure 6). Discussion\nThe high surface temperatures reached by the salt flats in the middle of the day are a\nchallenge for organisms living in this ecosystem, including tiger beetles. The results of this study\n223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249\nPeerJ reviewing PDF | (v2013:07:669:1:0:NEW 24 Aug 2013)\nR ev ie w in g M an\nus cr ip t\nsuggest that these species have evolved multiple mechanisms for coping with the high temperatures found on the salt flats. Because these mechanisms vary among species, these results imply that co-occurring species of adult tiger beetles within this system are segregating their foraging through behavioral differences associated with temperature. Shade-seeking behavior during the heat of the day is a common behavior seen in many organisms. Interestingly, C. n. lincolniana is very active during the hottest part of the day while other species of salt flat tiger beetles spend much of their time seeking refuge in the shade. This difference is probably not due to differences in physiology, but rather associated with differences in their behavior. Unlike other species C. n. lincolniana spends over a third of its time foraging in shallow seeps. During this foraging, what we observed as mandible dipping is probably two different types of behavior. Tiger beetles drink water by sinking their mandibles into a damp substrate. We observed tiger beetles taking a few seconds to hydrate using this behavior, however, when mandible dipping C. n. lincolniana would frequently come up with a small insect larva that it would quickly consume. Even in the hottest part of the day C. n. lincolniana was able to forage while in the shade of the salt grass growing in the seeps. Additionally, the seemingly unique behavior of abdomen dipping by C. n. lincolniana suggests that wetting the abdomen might be another mechanism for heat reduction. Differences in habitat use and foraging behavior allow C. n. lincolniana to be active during the hottest part of the day. This unique foraging behavior probably explains the large difference in mandible dipping frequency between species (Table 4, Figure 5a). There also was a temporal component to foraging by C. n. lincolniana as they would move out of the water and further out onto the salt flats as evening approached. We observed few other tiger beetle species after 19:00 hours. Cicindela fulgida was the only species of tiger beetles we observed that is classified as a spring-fall species. Spring-fall species of tiger beetle emerge as adults in the fall and overwinter as adults in contrast to summer species which over winter as larvae and emerge as adults in the 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275\nPeerJ reviewing PDF | (v2013:07:669:1:0:NEW 24 Aug 2013)\nR ev ie w in g M an\nus cr ip t\nspring. The adult beetles of this species that we were observing had overwintered as adult beetles and had been active as early as March (possibly even warm days in February). We expected that C. fulgida would have a more difficult time dealing with extreme temperatures, and C. fulgida did spent the most time on damp substrate and in the shade (Figure 2c and 3c). This species also spent a large proportion of the morning hours basking (Figure 4c), presumably in an effort to warm their body temperature. Cicindela circumpicta spent more time on dry substrates as temperatures rose during the day. Most of the shade on the salt flats is provided by vegetation which grows on the perimeter of the flat. This area has dry substrate because of the distance from the seep. As the temperatures dropped later in the day C. circumpicta appeared to move back onto damp surfaces to forage (Figure 3a). Cicindela circumpicta also spent a large proportion of their time basking in the early morning hours (Figure 4a). It is possible that the larger body mass of C. circumpicta requires more basking to raise its body temperature. Cicindela togata spent the most time on dry surfaces. Unlike C. circumpicta who moved to dry surfaces during the hottest part of the day and moved back to damp surfaces C. togata appears to spend all of its time on dry soils. The time spent on damp soils in the morning is likely a result of the lack of dry soil due to morning condensation. Cicindela circumpicta and C. togata have the same tolerance to heat yet they forage in different microhabitats on the flats (Hoback, Higley, & Stanley, 2001). Hoback, Higley, & Stanley (2001) theorized that microhabitat differences in foraging was a consequence of C. togata avoiding being preyed upon by C. circumpicta. In support of this notion, laboratory studies demonstrated that C. togata\u2019s behavior is modified by the presence of C. circumpicta. Because C. circumpicta is the largest of the salt marsh tiger beetles, other species may have adapted different foraging behaviors to avoid contact with C. circumpicta to avoid predation as well as to reduce competition in foraging. An alternative (or possibly complimentary) explanation for C. togata use of microhabits was suggested by one of our anonymous reviewers. Because C. togata has the smallest body size 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301\nPeerJ reviewing PDF | (v2013:07:669:1:0:NEW 24 Aug 2013)\nR ev ie w in g M an\nus cr ip t\nand longer legs than other tiger beetles we studied, C. togata can heat and cool more rapidly than other species (Pearson & Vogler, 2001). Given this advantage, C. togata may be able to use dry substrates when foraging more effectively than other species (who may have great thermoregulation issues). Wing pumping by tiger beetles is thought to be a thermoregulatory behavior to release heat (Pearson & Vogler, 2001), but C. togata (which had the highest per hour average) pumped its wings at a greater frequency in the morning. Cicindela fulgida and C. circumpicta both appeared to pump their wings with greater frequency in the middle of the day but did not show a direct association with temperature (Figure 6). Conclusions\nHow tiger beetles allocate their time in relation to temperature has been studied\nextensively (Dreisig, 1980; Dreisig, 1981; Dreisig, 1984; Dreisig, 1985; Morgan, 1985; Pearson & Lederhouse, 1987; Schultz & Hadley, 1987; Schultz, Quinlan, & Hadley, 1991; Schultz, 1998; Hoback, Higley, & Stanley, 2001; Romey & Knisley, 2002). Our results indicate that temperature, as well as potential competitive relationships among Cicindelida species, appears to be tied into what substrate beetles chose to occur on, whether or not they chose to spend time in the sunlight, and what behaviors they exhibited. In contrast to what might be expected for the endangered member of this assemblage, C. n. lincolniana clearly demonstrates behaviors that afford it advantages in accommodating high temperatures and avoiding potential competition with other tiger beetles. Key to these behaviors is the species reliance shallow water of the seeps for their diurnal foraging behavior (potentially limiting their foraging habitat), but with the advantage of allowing foraging during the hottest times of the day when potential competitors are less frequent. Indeed, by frequenting water, C. n. lincolniana was able to remain active in sunlight far more that other species, and maintain its activity over a longer portion of the day. The endangered status of C. n. lincolniana requires that those involved with the conservation of this insect examine its habitat requirements closely. Because this beetle appears\n302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328\nPeerJ reviewing PDF | (v2013:07:669:1:0:NEW 24 Aug 2013)\nR ev ie w in g M an\nus cr ip t\nto have reduced competition over food resources by adapting to forage in a unique environment they may be more susceptible to habitat destruction. Organisms that are highly specialized, such as C. n. lincolniana, are thought to be more susceptible to extinction due to habitat destruction (Kammer, Baumiller, & Ausich, 1997; Kotiaho et al., 2005). The shallow seeps found in saline wetlands have been destroyed by the channelization of these water ways over the last 100 years. Consequently, the close association of C. n. lincolniana with seeps and associated shallow pools seems to let C. n. lincolniana adults forage at times when temperatures may limit foraging for other saline-adapted tiger beetles. Ironically, this association also may help explain C. n. lincolniana\u2018s susceptibility to extinction: beyond the loss of saline wetlands generally, limited seeps and pools even within remaining saline habitat may represent a further habitat limitation within an already limited habitat. Acknowledgements We thank Drew Tyre for suggestions regarding data analysis, and Lauren Thompson, Mitch Paine, and Carmen Mostek for their assistance with recording behavior data (on some very hot days!). We also thank Lauren for her diligence in helping transcribe hours of behavior recordings. Finally, we appreciate the helpful comments of our anonymous reviewers, particularly the suggestions regarding C. togata foraging behaviors and microhabitat choice. References Cited Allgeier WJ. 2005. The behavioral ecology and abundance of tiger beetles inhabiting the Eastern Saline Wetlands of Nebraska. M.S. Thesis. University of Nebraska, Lincoln Nebraska Dreisig H. 1980. Daily activity, thermoregulation and water loss in the tiger beetle Cicindela hybrid. Oecologia 44:376-389. Dreisig H. 1981. The rate of predation and its temperature dependence in a tiger beetle, Cicindela hybrid. Oikos 36:196-202. Dreisig H. 1984. Control of body temperature in shuttling ectotherms. 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GraphPad InStat 3.0 User's Guide, GraphPad Software, Inc., San Diego California USA, www.graphpad.com. Pearson, DL, Vogler AP. 2001. Tiger beetles: the evolution, ecology, and diversity of the cicindelids. Cornell University Press, Ithaca, NY. Pearson DL. 1980.Patterns of limiting similarity in tropical forest tiger beetles (Coleoptera:\nCicindelidae). Biotropica 12:195-204.\n357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385\nPeerJ reviewing PDF | (v2013:07:669:1:0:NEW 24 Aug 2013)\nR ev ie w in g M an\nus cr ip t\nPearson DL, Juliano SA. 1991. Mandible length ratios as a mechanism for co-occurrence:\nEvidence from a world-wide comparison of tiger beetle assemblages (Cicindelidae). Oikos 61:223-233.\nPearson DL, Knisley CB. 1985. Evidence for food as a limiting source in the life cycle of tiger beetles (Coleoptera: Cicindelidae). Oikos 45:161-168.\nPearson DL, Lederhouse RC. 1987. Thermal ecology and the structure of an assemblage of adult tiger beetle species (Coleoptera: Cicindelidae). Okios 50:247-255. Pearson DL, Mury EJ. 1979. Character divergence and convergence among tiger beetles (Coleoptera: Cicindelidae). Ecology 60: 557-566. Pearson DL, Stemberger SL. 1980. Competition, body size, and relative energy balance of adult\ntiger beetles (Coleoptera: Cicindelidae). American Midlands Naturalist 104:373-377.\nPearson DL, Vogler AP. 2001. Tiger beetles: the evolution, ecology, and diversity of the\ncicindelids. Cornell University Press, Ithaca, NY.\nRomey WL, Knisley CB. 2002. Microhabitat segregation of two Utah sand dune tiger beetles\n(Coleoptera: Cicindelidae). Southwestern Entomologist 147:169-174.\nShelford VE. 1913 . The life-history of a bee-fly (Spogostylum anale Say) parasite of the larva of\na tiger beetle (Cicindela scutellaris Say var. lecontei Hald.) Annals of the Entomological Society of America 6:213-225.\nSchultz TC. 1998. The utilization of patchy thermal microhabitats by ectothermic insect predator, Cicindela sexguttata. Ecological Entomology 23:444-450. Schultz TC, Quinlan MC, Hadley NF. 1991. Preferred body temperature, metabolic physiology,\nand water balance of adult Cicindela longilabris: A comparison of populations from\nboreal habitats and climatic refugia. Physiological Zoology 65:226-242. Schultz TC, Hadley NF. 1987. Microhabitat segregation and physiological differences in co-\noccurring tiger beetle species, Cicindela oregona and Cicindela tranquebarica. Oecologia 73:363-370.\nSpomer SM, Higley LG. 1993. Population and distribution of the Salt Creek\n386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403 404 405 406 407 408 409 410 411 412 413\nPeerJ reviewing PDF | (v2013:07:669:1:0:NEW 24 Aug 2013)\nR ev ie w in g M an\nus cr ip t\ntiger beetle, Cicindela nevadica lincolniana Casey (Coleoptera: Cicindelidae). Journal of\nthe Kansas Entomological Society 66:392-398. Spomer SM, Higley LG, Hoback WW. 1997. Nebraska\u2019s salt marsh tigers.\nMuseum Notes University of Nebraska 97:1-4.\nWillis HL. 1967. Bionomics and zoogeography of tiger beetles of saline habitats in the central\nUnited States (Coleoptera: Cicindelidae). University of Kansas Science Bulletin 47:145- 313.\n414 415 416 417 418 419 420\nPeerJ reviewing PDF | (v2013:07:669:1:0:NEW 24 Aug 2013)\nR ev ie w in g M an\nus cr ip t\nMorning and afternoon/evening differences across species were evaluated with a MannWhitney test. Species differences (within morning or afternoon/evening) were determined by Kruskal-Wallis Test through non-parametric ANOVA (K-W test statistic corrected for ties and",
    "v2_Abstract": "How behavioral patterns are related to niche partitioning is an important question in understanding how closely related species within ecological communities function. Behavioral niche partitioning associated with thermoregulation is well documented in tiger beetles as a group. Co-occurring species of salt flat tiger beetles have adapted many thermoregulatory behaviors to cope with this harsh ecosystem. On first examination these beetles appear to occur in overlapping microhabitats and therefore compete for resources. To determine if behavioral niche partitioning is allowing multiple species to occur within the same harsh salt flat ecosystem we observed Cicindela nevadica lincolniana, Cicindela circumpicta, Cicindela fulgida, and Cicindela togata between 8:00 hours and 21:00 hours and recorded all behaviors related to thermoregulation using a digital voice recorder. Results of this study strongly indicate that competition among these species for resources has been reduced by the adaptation of different thermoregulatory behaviors such as spending time in shallow water, avoiding the sun during the hottest parts of the day, and by positioning their body against or away from the soil. The endangered C. n. lincolniana appears to rely most heavily on the shallow water of seeps for their diurnal foraging behavior (potentially limiting their foraging habitat), but with the advantage of allowing foraging during the hottest times of the day when potential competitors are less frequent. Ironically, this association also may help explain C. n. lincolniana\u2018s susceptibility to extinction: beyond the loss of saline wetlands generally, limited seeps and pools even within remaining saline habitat may represent a further habitat limitation within an already limited habitat. 3 4 19",
    "v2_col_introduction": "introduction  : Competition is one of the main forces driving niche partitioning and, consequently, speciation. Interspecific competition may lead to segregation among or within habitats followed by adaptations to different microhabitats (Schultz & Hadley, 1987). Ultimately, adaptation through selection is genetic but the phenotypic expression of selection may take many forms. Although we commonly think of physiological and morphological changes as products of selection through niche partitioning, variation in the behavior of sympatric species also can be a mechanism for niche partitioning. Harsh environments, where the biota is reduced and physiological adaptation is essential for survival, present ideal laboratories for examining the interplay of adaptation and competition. In such systems, the strong selection pressure associated with the physical environment provides a stage upon which interspecific competition plays. Saline wetlands, and their associated salt flats are one such harsh environment. The saline wetlands of eastern Nebraska are home to a unique cast of adapted organisms. Along with saline requirements in these organisms\u2019 life histories, many also are adapted to tolerate the harsh, desert-like environment typically associated with salt flats during the summer months (Farrar & Gersib, 1991). Within this environment exists a large assemblage of congeneric, sympatric tiger beetle species, including the endangered species Cicindela nevadica lincolniana (Willis 1967; Spomer & Higley, 1993; Spomer, Higley, & Hoback, 1997). Because of the uniqueness of this environment and the endangered status of one of these beetle species much attention has been given to this group of tiger beetles. Behaviors that serve to partition resources and reduce physiological stress have been examined for many species of tiger beetles, Cicindelidae, but much remains to be discovered about the diversity and functions of tiger beetle behavior (Pearson & Mury, 5 6 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65\nPeerJ reviewing PDF | (v2013:07:669:0:1:NEW 23 Jul 2013)\nR ev ie w in g M an\nus cr ip t\n4 1979; Pearson 1980; Pearson & Stemberger, 1980; Pearson & Knisley, 1985; Ganeshaiah & Belavadi, 1986; Schultz & Hadley, 1987; Hoback et al., 2000; Hoback, Higley, & Stanley et al., 2001; Romey & Knisley, 2002). Past and current research supports the theory that these tiger beetles are using oviposition as a mechanism for niche partitioning (Hoback et al., 2000; Hoback, Higley, & Stanley, 2001; Allgeier, 2005). Tiger beetle larvae do not move more than a few cm from where their eggs are originally deposited by the female. Among three salt marsh tiger beetle species (C. n. lincolniana, C. circumpicta, and C. togata) we observed oviposition differences based on soil salinity (Algeier 2006; Brosius 2010).This unique life history trait along with the larval dependence on limited prey resources for proper development (Mury Meyer, 1987) emphasizes the importance of the location chosen for oviposition. Prey also are essential to adult female fecundity. The amount of prey consumed by adult females is directly tied to their ability to lay greater numbers of eggs (Pearson & Knisley, 1985). The ability to lay more eggs can be important to the success of individual populations given high mortality in the larval stages. For example, Shelford (1913) documented the mortality of some populations of Cicindela scutellaris to be as high as 80% due to the parasitoid Anthrax sp., and Knisley and Shultz (1997) documented a mortality rate upwards around 63% from tiphiid wasps. Because females must gain enough caloric resources for egg production and development, it is likely that adult tiger beetle assemblages have evolved behaviors to reduce interspecific competition as adults. In particular, beyond direct competition for prey (e.g., Hoback et al., 2001), competition may be mediated through partitioning of foraging habitats: spatially, seasonally, or temporally. In this partitioning, temperature tolerance to the foraging habitat may play a key role. 7 8 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89\nPeerJ reviewing PDF | (v2013:07:669:0:1:NEW 23 Jul 2013)\nR ev ie w in g M an\nus cr ip t\n5 There is a long history of thermoregulation studies that focus on tiger beetles and\nthat link thermoregulation behaviors to resource partitioning (Dreisig, 1980; Dreisig, 1981; Dreisig, 1984; Dreisig, 1985; Morgan, 1985; Pearson & Lederhouse, 1987; Schultz & Hadley, 1987; Schultz, Quinlan, & Hadley, 1991; Schultz, 1998; Hoback, Higley, & Stanley, 2001; Romey & Knisley, 2002). Many tiger beetles are found in environments where temperatures are capable of exceeding 60\u00b0C, a lethal temperature for most insect species (Hadley 1994). From these studies it is clear that Cicindela are capable of regulating their body temperatures by changing their body orientation and shuttling between microclimates. Adult tiger beetles spend a high percentage of their day balancing foraging behavior with behaviors associated with thermoregulation. Pearson and Stemberger (1980) determined that the gain of one hour of additional foraging could increase the biomass of ingested prey by as much as 20%. This increase in prey would translate into an increase in egg production for adult females. Physiological character divergence in species\u2019 ability to cope with temperatures could be a mechanism to reduce intraguild predation. Differences in heat tolerances between species is a likely mechanism to reduce competition, however, a close examination of lethal maximum temperature of 13 tiger beetle species near Willcox, Arizona, USA revealed very few differences between upper heat tolerances among species (Pearson & Lederhouse 1987). Out of the 13 species examined in this study only 2 were found to be significantly different and the difference was less than one degree from the overall mean of 48.1\u00b0 C. Hoback, Higley, & Stanley (2001) determined the lethal maximum temperature for two species of tiger beetles (Cicindela circumpicta and Cicindela togata) within the complex of co-occurring species in the Eastern saline wetlands of Nebraska and found no differences between species, with results similar to\n9 10 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113\nPeerJ reviewing PDF | (v2013:07:669:0:1:NEW 23 Jul 2013)\nR ev ie w in g M an\nus cr ip t\n6 values observed by Pearson and Lederhouse (1987) with different Cicindela species. While tiger beetle species may have some variation in their ability to cope with varying degrees of humidity and temperature (Pearson & Lederhouse, 1987; Schultz & Hadley, 1987; Schultz, Quinlan, & Hadley, 1991) physiological differences cannot account for all behavioral differences observed in the field. To determine the evolutionary cause for such differences, Hoback, Higley, and Stanley (2001) investigated lethal high temperatures, prey base, prey size, mobility, and the effect of direct predation of C. togata by C. circumpicta. Laboratory studies that investigated feeding behavior of C. togata in both the absence and presence (separated by a clear pane of glass) of C. circumpicta indicated that C. togata feeding behavior was negatively affected by the presence of C. circumpicta. These results coupled with field observations strongly indicated that intra-guild predation was possible among salt marsh tiger beetles. In the case of C. n. lincolniana and its co-occurring Cicindela species it is likely that similar evolutionary forces as seen in earlier studies are at work. Past research strongly suggests that behaviors associated with the reduction of predation, thermoregulation, foraging, and predator avoidance may reduce competition among sympatric, adult tiger beetles (Pearson & Mury, 1979; Schultz & Hadley, 1987; Pearson & Juliano, 1991; Romey & Knisley, 2002). Consequently, we examined diurnal behavior of foraging salt marsh Cicindela species, with particular focus on potential differences in thermoregulatory behaviors. In particular, given the endangered species status of C. n. lincolniana, we were interested in identifying any unique adaptations that might contribute to population declines different from the other salt marsh tiger beetle species. Methods and Materials 11 12 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137\nPeerJ reviewing PDF | (v2013:07:669:0:1:NEW 23 Jul 2013)\nR ev ie w in g M an\nus cr ip t\n7 During the summer of 2007 initial observations were made of three species of\nsaline adapted tiger beetles: C. circumpicta, C. togata, and, C. n. lincolniana at the Arbor Lake Complex, Lincoln, NE. From these initial observations it appeared that these tiger beetles exhibit a large variety of behaviors and use a wide range of microhabitats. Behaviors associated with thermoregulation were of particular interest. Based on the 2007 data, an ethogram or catalogue of discrete behaviors was developed. Observations were classified specifically as states, events, and behaviors. \u201cStates\u201d described physical aspects of the environments, here, temperature, light, and substrate. Temperature included measures of soil-surface temperature, 1cm above the soil (comparable to tiger beetle body height), and ambient (1m) air temperatures. Light indicated if the subject was standing in the sun or shade. Substrate indicated if the subject was on dry soil, mud, or shallow water (typically on water near seeps or on algal mats along stream margins). \u201cBehaviors\u201d included running, stilting, basking, and standing. Stilting occurs when the tiger beetle holds itself up off of the substrate with its front two legs extended straight downward. Often the beetles appear to be standing at a 45\u00b0 angle from the vertical. Stilting occurs during the hottest time of day in an effort to reduce surface area and keep bodies away from the hot soil surface (Pearson & Vogler, 2001). Basking occurs when the tiger beetle presses its body up to the substrate in an effort to warm its body in the early morning hours (Pearson & Vogler, 2001). \u201cEvents\u201d were recorded when individuals exhibited a behavior that had no measurable time duration. Events included mandible dipping (dipping mandibles into the substrate beetles were are standing on), wing pumping (a quick opening and closing of their elytra), flight (this event had a measurable time duration but we almost always lost\n13 14 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161\nPeerJ reviewing PDF | (v2013:07:669:0:1:NEW 23 Jul 2013)\nR ev ie w in g M an\nus cr ip t\n8 track of the individual), and abdomen dipping (the individual would dip its abdomen into the water by doing what appeared to be a quick pushup). Behaviors of four co-occurring species of tiger beetles were examined on 20 June 2008, 30 June 2008, 7 July 2008, 23 June 2009, and 2 July 2009. Dates were chosen based on the predicted weather. We chose days that were predicted to have average or above average temperature with no precipitation. Species included C. circumpicta and C. togata, C. n. lincolniana, and the spring-fall species C. fulgida (which occasionally occurred in early summer). Behavior, states, and events were recorded using digital voice recorders and later transcribed using the program JWatcherTM (Version 1.0). One recording was made for each hour in the field. For each hour, three or four observers were randomly assigned a species to observe. Recordings were made from the first individual of that species the observer could locate using close-focus binoculars. At the start of each recording the observer noted the date, time, species, and, observer name. The observer watched one individual as long as they could in a 30 minute period. If recordings were less than 10 minutes in length the observer recorded a second individual of the same species for that hour. On the rare occasion that no species of that individual could be found (after at least 15 minutes of looking) the observer selected the first tiger beetle that they could find for recording observations. Along with these behaviors hourly temperatures were recorded. The surface temperature was taken from the area near where the recordings were being made. Temperature measurements were taken at 1 meter and 1 cm elevation from the same location. Because tiger beetle\u2019s bodies are approximately 1 cm above the soil surface, we used 1 cm measurement to reflect the temperatures being experienced by the beetles. The data were entered into the program JWatcher. For each block of time, we averaged time spent exhibiting individual behaviors (basking, running, standing, and 15 16 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186\nPeerJ reviewing PDF | (v2013:07:669:0:1:NEW 23 Jul 2013)\nR ev ie w in g M an\nus cr ip t\n9 stilting), time spent in sun or shade, and time spent on type of substrate (mud, dry soil, and water). Because times that each individual was watched varied, we converted the time spent to percentages for species comparisons. Events were averaged by hour by species. Analysis. Statistical differences were examined by using non-parametric approaches, because data were not normally distributed and could not be transformed to meet normality requirements. We used non-parametric procedures in GraphPad InStat (version 3.10 for Windows, GraphPad Software, San Diego California USA, www.graphpad.com) for analyses. These procedures included Mann-Whitney tests or non-parametric ANOVA with Kruskal-Wallis Test (corrected for ties) for overall significance, and Dunn\u2019s Multiple Comparison for separating species where the KurskalWallis indicated a significant overall effect. The logic of statistical choices and limitations follow that of Motulky (2009). Responses to state and behavior variables were analyzed by determining the mean time in a state for two periods: morning (8:00-11:00) and afternoon (11:00-21:00). The decision to subdivide the day into these two periods was made a priori based on the expectation of substantial temperature and behavioral differences at these times of day (based on published research and our own previous observations). Events were analyzed based on mean counts per day (i.e., the number of occurrences of each event). States, behaviors, and events were analyzed across species and within species. For analysis purposes the combination of day and different individuals within a species represents our replications. Additionally, randomly assigning different observers to record behaviors for different species each hour was used to minimize any potential bias among observers recording behaviors. Results 17 18 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211\nPeerJ reviewing PDF | (v2013:07:669:0:1:NEW 23 Jul 2013)\nR ev ie w in g M an\nus cr ip t\n10\nStates. State variables of association with temperature, light, and substrate\ndiffered with time of day and among species (Figures 1-4). Temperatures increased until 15:00 in all measurements (Figure 1). As a result of the absorption of solar radiation, soil temperature became higher than ambient and 1 cm air temperatures after 11:00. At 08:00 the surface temperature was more than 1\u00b0C cooler than 1 cm above the surface and ambient temperature. By 15:00 the surface temperature was 7.9\u00b0C higher than at 1 cm above the surface. At 08:00 there was almost no difference between ambient temperature and 1 cm above the soil surface (0.12\u00b0C). At 16:00 hours the difference rose to 1.9\u00b0C. Temperatures dropped dramatically between 20:00 and 21:00. At 1 cm above the salt flat surface, temperatures dropped 5.4\u00b0C. Time spent in the sun was directly linked to the time of day and, therefore, temperature. For all species time spent in the sun was significantly higher in the morning (08:00-11:00) when the salt flat temperatures were the coolest (Figure 2, Table 1). As temperatures rose the amount of time spent in the shade increased for all species (Figure 2). Significant differences in percentages of time spent in the sun were found between species. Cicindela nevadica lincolniana spent the most time in the sun throughout the day (77.1% of their total time) (Figure 2, Table 1). Cicindela togata spent the most amount of time on dry soils (Figure 3, Table 2). Cicindela nevadica lincolniana spent significantly more time standing on the damp surfaces and in the shallow water of the seeps than the other species observed (Figure 3, Table 2). Both C. circumpicta and C. fulgida spent the majority of their time on damp substrate as opposed to dry soil (Figures 3a & 3c, Table 2). Cicindela circumpicta spent more time on dry substrate when temperatures rose in the late afternoon (Figure 3a, Table\n19 20 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234\nPeerJ reviewing PDF | (v2013:07:669:0:1:NEW 23 Jul 2013)\nR ev ie w in g M an\nus cr ip t\n11\n2). Cicindela fulgida spent the most amount of their time on damp substrate (60.1% total) and time spent on damp substrate increased with temperature (Figure 3c, Table 3). Another important difference in habitat use was indicated by associations with standing in water (at margins of seeps and streams). Of the species observed, during the hottest parts of the day C. n. lincolniana spent over a third of the time in water, while other species spent little or no time in water (Figure 3, Table 4). Behaviors. All four species of tiger beetle spent a large portion of their time alternating between standing and running (Figure 4). This reflects typical tiger beetle foraging behavior where they alternate between running in short bursts and standing watching for prey (Pearson & Juliano, 1991). Cicindela togata had the largest shift between running and standing in the middle of the day (Figure 4d). Basking was almost always associated with morning hours (before 11:00) and evening hours (after 16:00), with more than three times more basking in the morning than later. Across species, basking occurred 15.5% of the time before 11:00 versus 5.1% of time after 11:00 (Mann-Whitney U = 13.86, P < 0.0001). This difference lined up with the coolest hours of the day. Stilting was almost completely associated with the middle parts of the day for all four species. Cicindela circumpicta spent more time basking in the early hours (Figure 4a). Events. The total events per hour were averaged over the entire day for all four species (Table 5). Cicindela nevadica lincolniana was the only species to display abdomen dipping into water (Table 5). Similarly, C. n. lincolniana averaged 78.05 mandible dips per hour, which was far greater than C. circumpicta which was the next highest at 5.44 mandible dips per hour. Cicindela togata averaged 0.88 flights per hour, which was greater than C. fulgida which was the next highest at 0.51 flights per hour. Cicindela togata appeared to make many short flights during the 8:00 time block but\n21 22 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259\nPeerJ reviewing PDF | (v2013:07:669:0:1:NEW 23 Jul 2013)\nR ev ie w in g M an\nus cr ip t\n12\nshort flights seemed to have no other significant correlation to time of day for any other tiger beetle species (Figure 5). Wing pumping occurred in greater frequency in C. n. lincolniana earlier in the day but appeared to occur with greater frequency later in the day for C. circumpicta (Figure 6). Discussion\nThe high surface temperatures reached by the salt flats in the middle of the day\nare a challenge for organisms living in this ecosystem, including tiger beetles. The results of this study suggest that these species have evolved multiple mechanisms for coping with the high temperatures found on the salt flats. Because these mechanisms vary among species, these results imply that co-occurring species of adult tiger beetles within this system are segregating their foraging through behavioral differences associated with temperature. Shade-seeking behavior during the heat of the day is a common behavior seen in many organisms. Interestingly, C. n. lincolniana is very active during the hottest part of the day while other species of salt flat tiger beetles spend much of their time seeking refuge in the shade. This difference is probably not due to differences in physiology, but rather associated with differences in their behavior. Unlike other species C. n. lincolniana spends over a third of its time foraging in shallow seeps. During this foraging, what we observed as mandible dipping is probably two different types of behavior. Tiger beetles drink water by sinking their mandibles into a damp substrate. We observed tiger beetles taking a few seconds to hydrate using this behavior, however, when mandible dipping C. n. lincolniana would frequently come up with a small insect larva that it would quickly consume. Even in the hottest part of the day C. n. lincolniana was able to forage while in the shade of the salt grass growing in the seeps. Additionally, the seemingly unique\n23 24 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283\nPeerJ reviewing PDF | (v2013:07:669:0:1:NEW 23 Jul 2013)\nR ev ie w in g M an\nus cr ip t\n13\nbehavior of abdomen dipping by C. n. lincolniana suggests that wetting the abdomen might be another mechanism for heat reduction. Differences in habitat use and foraging behavior allow C. n. lincolniana to be active during the hottest part of the day. This unique foraging behavior probably explains the large difference in mandible dipping frequency between species (Table 4, Figure 5a). There also was a temporal component to foraging by C. n. lincolniana as they would move out of the water and further out onto the salt flats as evening approached. We observed few other tiger beetle species after 19:00 hours. Cicindela fulgida was the only species of tiger beetles we observed that is classified as a spring-fall species. Spring-fall species of tiger beetle emerge as adults in the fall and overwinter as adults in contrast to summer species which over winter as larvae and emerge as adults in the spring. The adult beetles of this species that we were observing had overwintered as adult beetles and had been active as early as March (possibly even warm days in February). We expected that C. fulgida would have a more difficult time dealing with extreme temperatures, and C. fulgida did spent the most time on damp substrate and in the shade (Figure 2c and 3c). This species also spent a large proportion of the morning hours basking (Figure 4c), presumably in an effort to warm their body temperature. Cicindela circumpicta spent more time on dry substrates as temperatures rose during the day. Most of the shade on the salt flats is provided by vegetation which grows on the perimeter of the flat. This area has dry substrate because of the distance from the seep. As the temperatures dropped later in the day C. circumpicta appeared to move back onto damp surfaces to forage (Figure 3a). Cicindela circumpicta also spent a large proportion of their time basking in the early morning hours (Figure 4a). It is possible that\n25 26 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307\nPeerJ reviewing PDF | (v2013:07:669:0:1:NEW 23 Jul 2013)\nR ev ie w in g M an\nus cr ip t\n14\nthe larger body mass of C. circumpicta requires more basking to raise its body temperature. Cicindela togata spent the most time on dry surfaces. Unlike C. circumpicta who moved to dry surfaces during the hottest part of the day and moved back to damp surfaces C. togata appears to spend all of its time on dry soils. The time spent on damp soils in the morning is likely a result of the lack of dry soil due to morning condensation. Cicindela circumpicta and C. togata have the same tolerance to heat yet they forage in different microhabitats on the flats (Hoback, Higley, & Stanley, 2001). Hoback, Higley, & Stanley (2001) theorized that microhabitat differences in foraging was a consequence of C. togata avoiding being preyed upon by C. circumpicta. In support of this notion, laboratory studies demonstrated that C. togata\u2019s behavior is modified by the presence of C. circumpicta. Because C. circumpicta is the largest of the salt marsh tiger beetles, other species may have adapted different foraging behaviors to avoid contact with C. circumpicta to avoid predation as well as to reduce competition in foraging. Wing pumping by tiger beetles is thought to be a thermoregulatory behavior to release heat (Pearson & Vogler, 2001), but C. togata (which had the highest per hour average) pumped its wings at a greater frequency in the morning. Cicindela fulgida and C. circumpicta both appeared to pump their wings with greater frequency in the middle of the day but did not show a direct association with temperature (Figure 6). Conclusions\nHow tiger beetles allocate their time in relation to temperature has been studied\nextensively (Dreisig, 1980; Dreisig, 1981; Dreisig, 1984; Dreisig, 1985; Morgan, 1985; Pearson & Lederhouse, 1987; Schultz & Hadley, 1987; Schultz, Quinlan, & Hadley, 1991; Schultz, 1998; Hoback, Higley, & Stanley, 2001; Romey & Knisley, 2002). Our results indicate that temperature, as well as potential competitive relationships among\n27 28 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332\nPeerJ reviewing PDF | (v2013:07:669:0:1:NEW 23 Jul 2013)\nR ev ie w in g M an\nus cr ip t\n15\nCicindelida species, appears to be tied into what substrate beetles chose to occur on, whether or not they chose to spend time in the sunlight, and what behaviors they exhibited. In contrast to what might be expected for the endangered member of this assemblage, C. n. lincolniana clearly demonstrates behaviors that afford it advantages in accommodating high temperatures and avoiding potential competition with other tiger beetles. Key to these behaviors is the species reliance shallow water of the seeps for their diurnal foraging behavior (potentially limiting their foraging habitat), but with the advantage of allowing foraging during the hottest times of the day when potential competitors are less frequent. Indeed, by frequenting water, C. n. lincolniana was able to remain active in sunlight far more that other species, and maintain its activity over a longer portion of the day. The endangered status of C. n. lincolniana requires that those involved with the conservation of this insect examine its habitat requirements closely. Because this beetle appears to have reduced competition over food resources by adapting to forage in a unique environment they may be more susceptible to habitat destruction. Organisms that are highly specialized, such as in the case of C. n. lincolniana, are thought to be more susceptible to extinction due to habitat destruction (Kammer, Baumiller, & Ausich, 1997; Kotiaho et al., 2005). The shallow seeps found in saline wetlands have been destroyed by the channelization of these water ways over the last 100 years. Consequently, the close association of C. n. lincolniana with seeps and associated shallow pools seems to let C. n. lincolniana adults forage at times when temperatures may limit foraging for other saline-adapted tiger beetles. Ironically, this association also may help explain C. n. lincolniana\u2018s susceptibility to extinction: beyond the loss of saline wetlands generally,\n29 30 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356\nPeerJ reviewing PDF | (v2013:07:669:0:1:NEW 23 Jul 2013)\nR ev ie w in g M an\nus cr ip t\n16\nlimited seeps and pools even within remaining saline habitat may represent a further habitat limitation within an already limited habitat. Acknowledgements We thank Drew Tyre for suggestions regarding data analysis, and Lauren Thompson, Mitch Paine, and Carmen Mostek for their assistance with recording behavior data (on some very hot days!). We also thank Lauren for her diligence in helping transcribe hours of behavior recordings. References Cited Allgeier WJ. 2005. The behavioral ecology and abundance of tiger beetles inhabiting the\nEastern Saline Wetlands of Nebraska. M.S. Thesis. University of Nebraska,\nLincoln Nebraska Dreisig H. 1980. Daily activity, thermoregulation and water loss in the tiger beetle Cicindela hybrid. Oecologia 44:376-389. Dreisig H. 1981. The rate of predation and its temperature dependence in a tiger beetle, Cicindela hybrid. Oikos 36:196-202. Dreisig H. 1984. Control of body temperature in shuttling ectotherms. Journal of Thermal Biology 9:229-233. Dreisig H. 1985. A time budget model of thermoregulation in shuttling ectotherms. Journal of Arid Environments 8:191-205. Farrar J, Gersib D.. 1991 Nebraska Salt Marshes: Last of the Least. Nebraskaland Magazine 69:18-41. Ganeshaiah KN, Belavadi VV. 1986. Habitat segregation in four species of adult tiger beetles (Coleoptera: Cicindelidae). Ecological Entomology 11:147-154. Hadley NF. 1994. Water relations of terrestrial arthropods. Academic Press, New York,\nNY.\nHoback WW, Golick DA, Svatos TM, Spomer SM, Higley, LG. 2000. Salinity and shade preferences result in ovipositional differences between sympatric tiger beetle species. Ecological Entomology 25:180-187.\n31 32 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384\nPeerJ reviewing PDF | (v2013:07:669:0:1:NEW 23 Jul 2013)\nR ev ie w in g M an\nus cr ip t\n17\nHoback WW, Higley LG, Stanley DW. 2001. Tigers eating tigers: evidence of intraguild\npredation operating in an assemblage of tiger beetles. Ecological Entomology. 26:367-375.\nKammer TV, Baumiller TK, Ausich WI. 1997. Species longevity as a function of niche breadth: Evidence from fossil crinoids. Geology 25:219-222. Kotiaho JS, Kaitala V, Komonen A, P\u00e4ivinen J. 2005. Predicting the risk of extinction\nfrom shared ecological characteristics. Proceedings of the National Academy of Science 102:1963-1967.\nKnisley, CB, Schultz TD. 1997. The Biology of Tiger Beetles and a Guide to South Atlantic States. Special Publication No. 5 Virginia Museum of Natural History, Martinsville, VA. Morgan, KR 1985. Body temperature regulation and terrestrial activity in the ectothermic beetle Cicindela tranquebarica. Physiological Zoology 58:29-37 Mury Meyer, EJ. 1987. Asymmetric resource use in two syntopic species of larval tiger beetles (Cicindelidae). Oikos 50:16-175. Motulsky, HJ. 2009. GraphPad InStat 3.0 User's Guide, GraphPad Software, Inc., San Diego California USA, www.graphpad.com. Pearson, DL, Vogler AP. 2001. Tiger beetles: the evolution, ecology, and diversity of the cicindelids. Cornell University Press, Ithaca, NY. Pearson DL. 1980.Patterns of limiting similarity in tropical forest tiger beetles\n(Coleoptera: Cicindelidae). Biotropica 12:195-204.\nPearson DL, Juliano SA. 1991. Mandible length ratios as a mechanism for co-occurrence:\nEvidence from a world-wide comparison of tiger beetle assemblages (Cicindelidae). Oikos 61:223-233.\nPearson DL, Knisley CB. 1985. Evidence for food as a limiting source in the life cycle of tiger beetles (Coleoptera: Cicindelidae). Oikos 45:161-168.\nPearson DL, Lederhouse RC. 1987. Thermal ecology and the structure of an assemblage\nof adult tiger beetle species (Coleoptera: Cicindelidae). Okios 50:247-255.\n33 34 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403 404 405 406 407 408 409 410 411 412\nPeerJ reviewing PDF | (v2013:07:669:0:1:NEW 23 Jul 2013)\nR ev ie w in g M an\nus cr ip t\n18\nPearson DL, Mury EJ. 1979. Character divergence and convergence among tiger beetles (Coleoptera: Cicindelidae). Ecology 60: 557-566. Pearson DL, Stemberger SL. 1980. Competition, body size, and relative energy balance\nof adult tiger beetles (Coleoptera: Cicindelidae). American Midlands Naturalist 104:373-377.\nPearson DL, Vogler AP. 2001. Tiger beetles: the evolution, ecology, and diversity of the\ncicindelids. Cornell University Press, Ithaca, NY.\nRomey WL, Knisley CB. 2002. Microhabitat segregation of two Utah sand dune tiger\nbeetles (Coleoptera: Cicindelidae). Southwestern Entomologist 147:169-174.\nShelford VE. 1913 . The life-history of a bee-fly (Spogostylum anale Say) parasite of the\nlarva of a tiger beetle (Cicindela scutellaris Say var. lecontei Hald.) Annals of the Entomological Society of America 6:213-225.\nSchultz TC. 1998. The utilization of patchy thermal microhabitats by ectothermic insect predator, Cicindela sexguttata. Ecological Entomology 23:444-450. Schultz TC, Quinlan MC, Hadley NF. 1991. Preferred body temperature, metabolic\nphysiology, and water balance of adult Cicindela longilabris: A comparison of populations from boreal habitats and climatic refugia. Physiological Zoology\n65:226-242. Schultz TC, Hadley NF. 1987. Microhabitat segregation and physiological differences in\nco-occurring tiger beetle species, Cicindela oregona and Cicindela tranquebarica. Oecologia 73:363-370.\nSpomer SM, Higley LG. 1993. Population and distribution of the Salt Creek tiger beetle, Cicindela nevadica lincolniana Casey (Coleoptera: Cicindelidae). Journal of the Kansas Entomological Society 66:392-398. Spomer SM, Higley LG, Hoback WW. 1997. Nebraska\u2019s salt marsh tigers.\nMuseum Notes University of Nebraska 97:1-4.\n35 36 413 414 415 416 417 418 419 420 421 422 423 424 425 426 427 428 429 430 431 432 433 434 435 436 437 438 439\nPeerJ reviewing PDF | (v2013:07:669:0:1:NEW 23 Jul 2013)\nR ev ie w in g M an\nus cr ip t\n19\nWillis HL. 1967. Bionomics and zoogeography of tiger beetles of saline habitats in the\ncentral United States (Coleoptera: Cicindelidae). University of Kansas Science Bulletin 47:145-313.\n37 38 440 441 442\nPeerJ reviewing PDF | (v2013:07:669:0:1:NEW 23 Jul 2013)\nR ev ie w in g M an\nus cr ip t\nMorning and afternoon/evening differences across species were evaluated with a Mann-Whitney test. Species differences (within morning or afternoon/evening) were determined by Kruskal-Wallis Test through non-parametric ANOVA (K-W test statistic corrected for ties and P determined from chi-square distribution). Significant species comparisons were determined by Dunn\u2019s Multiple Comparisons Test (only results with P < 0.05 are shown.)\nPeerJ reviewing PDF | (v2013:07:669:0:1:NEW 23 Jul 2013)\nR ev ie w in g M an\nus cr ip t\nTable 1. Comparison of proportion of time spent in the sun by C. circumpicta, C. fulgida, C. n. lincolniana , and C. togata. Morning and afternoon/evening differences across species were evaluated with a Mann-Whitney test. Species differences (within morning or afternoon/evening) were determined by Kruskal-Wallis Test through non-parametric ANOVA (K-W test statistic corrected for ties and P determined from chi-square distribution). Significant species comparisons were determined by Dunn\u2019s Multiple Comparisons Test (only results with P < 0.05 are shown.)\nProportion of Time in Sun 8:00-21:00 M-W U P>F\nComparison: 8:00-11:00 vs. 11:00-21:00 719.5 < 0.0001 Times n Mean sd 8:00-11:00 28 0.92 0.14 11:00-21:00 139 0.69 0.29\n8:00-11:00 K-W (df = 3) P>X2\nComparison: species x species 1.43 ns Species n Mean sd C. circumpicta 7 0.91 0.21 C. fulgida 7 0.94 0.10 C. n. lincolniana 11 0.90 0.14 C. togata 3 0.98 0.03\n11:00-21:00 K-W (df = 3) P>X2\nComparison: species x species 9.07 = 0.0283 C. fulgida vs. C. n. lincolniana < 0.05\nSpecies n Mean sd C. circumpicta 41 0.67 0.23 C. fulgida 34 0.54 0.32 C. n. lincolniana 50 0.74 0.26 C. togata 14 0.62 0.41\nPeerJ reviewing PDF | (v2013:07:669:0:1:NEW 23 Jul 2013)\nR ev ie w in g M an\nus cr ip t\nMorning and afternoon/evening differences across species were evaluated with a Mann-Whitney test.",
    "v1_text": "abstract : How behavioral patterns are related to niche partitioning is an important question in understanding how closely related species within ecological communities function. Behavioral niche partitioning associated with thermoregulation is well documented in tiger beetles as a group. Co-occurring species of salt flat tiger beetles have adapted many thermoregulatory behaviors to cope with this harsh ecosystem. On first examination these beetles appear to occur in overlapping microhabitats and therefore compete for resources. To determine if behavioral niche partitioning is allowing multiple species to occur within the same harsh salt flat ecosystem we observed Cicindela nevadica lincolniana, Cicindela circumpicta, Cicindela fulgida, and Cicindela togata between 8:00 hours and 21:00 hours and recorded all behaviors related to thermoregulation using a digital voice recorder. Results of this study strongly indicate that competition among these species for resources has been reduced by the adaptation of different thermoregulatory behaviors such as spending time in shallow water, avoiding the sun during the hottest parts of the day, and by positioning their body against or away from the soil. The endangered C. n. lincolniana appears to rely most heavily on the shallow water of seeps for their diurnal foraging behavior (potentially limiting their foraging habitat), but with the advantage of allowing foraging during the hottest times of the day when potential competitors are less frequent. Ironically, this association also may help explain C. n. lincolniana\u2018s susceptibility to extinction: beyond the loss of saline wetlands generally, limited seeps and pools even within remaining saline habitat may represent a further habitat limitation within an already limited habitat. 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 PeerJ reviewing PDF | (v2013:07:669:1:0:NEW 24 Aug 2013) R ev ie w in g M an us cr ip t p determined from chi-square distribution). significant species comparisons were determined : by Dunn\u2019s Multiple Comparisons Test (only results with P < 0.05 are shown.) PeerJ reviewing PDF | (v2013:07:669:1:0:NEW 24 Aug 2013) R ev ie w in g M an us cr ip t Table 1. Comparison of proportion of time spent in the sun by C. circumpicta, C. fulgida, C. n. lincolniana , and C. togata. Morning and afternoon/evening differences across species were evaluated with a Mann-Whitney test. Species differences (within morning or afternoon/evening) were determined by Kruskal-Wallis Test through non-parametric ANOVA (K-W test statistic corrected for ties and P determined from chi-square distribution). Significant species comparisons were determined by Dunn\u2019s Multiple Comparisons Test (only results with P < 0.05 are shown.) Proportion of Time in Sun 8:00-21:00 M-W U P>F Comparison: 8:00-11:00 vs. 11:00-21:00 719.5 < 0.0001 Times n Mean sd 8:00-11:00 28 0.92 0.14 11:00-21:00 139 0.69 0.29 8:00-11:00 K-W (df = 3) P>X2 Comparison: species x species 1.43 ns Species n Mean sd C. circumpicta 7 0.91 0.21 C. fulgida 7 0.94 0.10 C. n. lincolniana 11 0.90 0.14 C. togata 3 0.98 0.03 11:00-21:00 K-W (df = 3) P>X2 Comparison: species x species 9.07 = 0.0283 C. fulgida vs. C. n. lincolniana < 0.05 Species n Mean sd C. circumpicta 41 0.67 0.23 C. fulgida 34 0.54 0.32 C. n. lincolniana 50 0.74 0.26 C. togata 14 0.62 0.41 PeerJ reviewing PDF | (v2013:07:669:1:0:NEW 24 Aug 2013) R ev ie w in g M an us cr ip t Morning and afternoon/evening differences across species were evaluated with a MannWhitney test. P values for Mann-Whitney are estimated (not exact) because of tied ranks. Species differences (within morning or afternoon/evening) were determined by Kruskal-Wallis Test through non-parametric ANOVA (K-W test statistic corrected for ties and P determined from chi-square distribution). Significant species comparisons were determined by Dunn\u2019s Multiple Comparisons Test (only results with P < 0.05 are shown.) PeerJ reviewing PDF | (v2013:07:669:1:0:NEW 24 Aug 2013) R ev ie w in g M an us cr ip t Table 2. Comparison of proportion of time spent on dry surfaces by C. circumpicta, C. fulgida, C. n. lincolniana , and C. togata. Morning and afternoon/evening differences across species were evaluated with a Mann-Whitney test. P values for Mann-Whitney are estimated (not exact) because of tied ranks. Species differences (within morning or afternoon/evening) were determined by Kruskal-Wallis Test through non-parametric ANOVA (K-W test statistic corrected for ties and P determined from chi-square distribution). Significant species comparisons were determined by Dunn\u2019s Multiple Comparisons Test (only results with P < 0.05 are shown.) Proportion of Time on Dry Substrate 8:00-21:00 M-W U P>F Comparison: 8:00-11:00 vs. 11:00-21:00 1514.0 = 0.0255 Times n Mean sd 8:00-11:00 28 0.14 0.33 11:00-21:00 139 0.69 0.29 8:00-11:00 K-W (df = 3) P>X2 Comparison: species x species 0.7793 ns Species n Mean sd C. circumpicta 7 0.14 0.37 C. fulgida 7 0.14 0.37 C. n. lincolniana 11 0.09 0.30 C. togata 3 0.33 0.57 11:00-21:00 K-W (df = 3) P>X2 Comparison: species x species 42.042 < 0.0001 C. circumpicta vs. C. n. lincolniana < 0.001 C. circumpicta vs. C. togata < 0.05 C. fulgida vs. C. n. lincolniana < 0.01 C. fulgida vs. C. togata < 0.01 C. n. lincolniana vs. C. togata < 0.001 Species n Mean sd C. circumpicta 41 0.46 0.48 C. fulgida 34 0.38 0.49 C. n. lincolniana 50 0.04 0.20 C. togata 14 0.62 0.34 PeerJ reviewing PDF | (v2013:07:669:1:0:NEW 24 Aug 2013) R ev ie w in g M an us cr ip t Morning and afternoon/evening differences across species were evaluated with a MannWhitney test. P values for Mann-Whitney are estimated (not exact) because of tied ranks. Species differences (within morning or afternoon/evening) were determined by Kruskal-Wallis Test through non-parametric ANOVA (K-W test statistic corrected for ties and P determined from chi-square distribution). Significant species comparisons were determined by Dunn\u2019s Multiple Comparisons Test (only results with P < 0.05 are shown.) PeerJ reviewing PDF | (v2013:07:669:1:0:NEW 24 Aug 2013) R ev ie w in g M an us cr ip t Table 3. Comparison of proportion of time spent on mud by C. circumpicta, C. fulgida, C. n. lincolniana , and C. togata. Morning and afternoon/evening differences across species were evaluated with a Mann-Whitney test. P values for Mann-Whitney are estimated (not exact) because of tied ranks. Species differences (within morning or afternoon/evening) were determined by Kruskal-Wallis Test through non-parametric ANOVA (K-W test statistic corrected for ties and P determined from chi-square distribution). Significant species comparisons were determined by Dunn\u2019s Multiple Comparisons Test (only results with P < 0.05 are shown.) Proportion of Time on Mud 8:00-21:00 M-W U P>F Comparison: 8:00-11:00 vs. 11:00-21:00 1645.5 ns Times n Mean sd 8:00-11:00 28 0.70 0.41 11:00-21:00 139 0.58 0.45 8:00-11:00 K-W (df = 3) P>X2 Comparison: species x species 5.900 ns Species n Mean sd C. circumpicta 7 0.85 0.38 C. fulgida 7 0.81 0.38 C. n. lincolniana 11 0.86 0.42 C. togata 3 0.67 0.58 11:00-21:00 K-W (df = 3) P>X2 Comparison: species x species 16.717 = 0.0008 C. circumpicta vs. C. togata < 0.05 C. fulgida vs. C. togata < 0.01 C. n. lincolniana vs. C. togata < 0.001 Species n Mean sd C. circumpicta 41 0.54 0.48 C. fulgida 34 0.61 0.49 C. n. lincolniana 50 0.72 0.35 C. togata 14 0.13 0.34 PeerJ reviewing PDF | (v2013:07:669:1:0:NEW 24 Aug 2013) R ev ie w in g M an us cr ip t Morning and afternoon/evening differences across species were evaluated with a MannWhitney test. P values for Mann-Whitney are estimated (not exact) because of tied ranks. Species differences (within morning or afternoon/evening) were determined by Kruskal-Wallis Test through non-parametric ANOVA (K-W test statistic corrected for ties and P determined from chi-square distribution). Significant species comparisons were determined by Dunn\u2019s Multiple Comparisons Test (only results with P < 0.05 are shown.) PeerJ reviewing PDF | (v2013:07:669:1:0:NEW 24 Aug 2013) R ev ie w in g M an us cr ip t Table 4. Comparison of proportion of time spent on water by C. circumpicta, C. fulgida, C. n. lincolniana , and C. togata. Morning and afternoon/evening differences across species were evaluated with a Mann-Whitney test. P values for Mann-Whitney are estimated (not exact) because of tied ranks. Species differences (within morning or afternoon/evening) were determined by Kruskal-Wallis Test through non-parametric ANOVA (K-W test statistic corrected for ties and P determined from chi-square distribution). Significant species comparisons were determined by Dunn\u2019s Multiple Comparisons Test (only results with P < 0.05 are shown.) Proportion of Time on Water 8:00-21:00 M-W U P>F Comparison: 8:00-11:00 vs. 11:00-21:00 1703.0 ns Times n Mean sd 8:00-11:00 28 0.15 0.30 11:00-21:00 139 0.08 0.22 8:00-11:00 K-W (df = 3) P>X2 Comparison: species x species 13.274 = 0.0041 C. circumpicta vs. C. n. lincolniana < 0.05 Species n Mean sd C. circumpicta 7 0 0 C. fulgida 7 0.05 0.12 C. n. lincolniana 11 0.36 0.40 C. togata 3 0 0 11:00-21:00 K-W (df = 3) P>X2 Comparison: species x species 44.754 < 0.0001 C. n. lincolniana vs. C. circumpicta < 0.001 C. n. lincolniana vs. C. fulgida < 0.001 C. n. lincolniana < 0.001 Species n Mean sd C. circumpicta 41 0 0 C. fulgida 34 0 0.03 C. n. lincolniana 50 0.23 0.32 C. togata 14 0 0 PeerJ reviewing PDF | (v2013:07:669:1:0:NEW 24 Aug 2013) R ev ie w in g M an us cr ip t Significant differences within an event were determined by Kruskal-Wallis Test through nonparametric ANOVA (K-W test statistic corrected for ties and P determined from chi-square distribution, df = 3). Significant species comparisons were determined by Dunn\u2019s Multiple Comparisons Test (only results with P < 0.05 are shown). PeerJ reviewing PDF | (v2013:07:669:1:0:NEW 24 Aug 2013) R ev ie w in g M an us cr ip t Table 5. Means and standard deviations (sd) of total behavioral events per hour averaged daily (11:00-21:00 for C. circumpicta, C. fulgida, C. n. lincolniana, and C. togata. Significant differences within an event were determined by Kruskal-Wallis Test through non-parametric ANOVA (K-W test statistic corrected for ties and P determined from chi-square distribution, df = 3). Significant species comparisons were determined by Dunn\u2019s Multiple Comparisons Test (only results with P < 0.05 are shown). Abdomen Dipping Mandible Dipping Wing Pumping Flying Species n mean sd mean sd mean sd mean sd C. circumpicta 41 0 0 5.4 10.3 4.0 4.8 0.20 0.46 C. fulgida 34 0 0 2.5 4.2 5.2 5.4 0.59 1.02 C. n. lincolniana 50 0.24 1.2 75.8 99.6 3.9 4.4 0.10 0.30 C. t gata 14 0 0 5.8 9.7 3.9 3.5 0.57 1.16.5 Comparison K-W P> X2 K-W P> X2 K-W P> X2 K-W P> X2 - - 55.50 <0.0001 0.626 ns 9.807 0.02 C. n. lincolniana vs. C. circumpicta < 0.001 C. n. lincolniana vs. C. fulgida < 0.001 < 0.05 C. n. lincolniana vs. C. togata < 0.01 PeerJ reviewing PDF | (v2013:07:669:1:0:NEW 24 Aug 2013) R ev ie w in g M an us cr ip t Figure 1 Average mandible dips, wing pumps, and flight events per hour. Average salt flat temperatures by hour. Temperatures were recorded on the salt flats where observations were made for adult tiger beetles. Temperatures were recorded one meter above the soil surface to determine ambient temperature, one cm above the soil surface to determine the air temperature the subjects were experiencing, and at the soil surface. PeerJ reviewing PDF | (v2013:07:669:1:0:NEW 24 Aug 2013) R ev ie w in g M an us cr ip t Figure 2 Time spent in sun or shade by tiger beetle species. Proportion of time spent in the sun or the shade between 8:00 and 21:00 hours (bars on graph) and soil surface temperature of the salt flats (dotted line) over those hours for four species of salt flat tiger beetle: a) C. circumpicta, b) C. n. lincolniana, c) C. fulgida, and d) C. togata. PeerJ reviewing PDF | (v2013:07:669:1:0:NEW 24 Aug 2013) R ev ie w in g M an us cr ip t Figure 3 Time spent on different substrates by tiger beetle species. Proportion of time spent on wet soil (mud), dry soil, and in shallow water between 8:00 and 21:00 hours (bars on graph) and soil surface temperature of the salt flats (dotted line) over those hours for four species of salt flat tiger beetle: a) C. circumpicta, b) C. n. lincolniana, c) C. fulgida, and d) C. togata. PeerJ reviewing PDF | (v2013:07:669:1:0:NEW 24 Aug 2013) R ev ie w in g M an us cr ip t Figure 4 Time spent engaging in thermoregulatory behavior. Proportion of time spent in four distinct behaviors related to thermoregulation between 8:00 and 21:00 hours (bars on graph), and soil surface temperature of the salt flats (dotted line) over those hours for four species of salt flat tiger beetle: a) C. circumpicta, b) C. n. lincolniana, c) C. fulgida, and d) C. togata. PeerJ reviewing PDF | (v2013:07:669:1:0:NEW 24 Aug 2013) R ev ie w in g M an us cr ip t Figure 5 Average mandible dips, wing pumps, and flight events per hour. A) Average recorded mandible dipping events per hour of observation for C. n. lincolniana and C. circumpicta (bars on graph), and soil surface temperature of the salt flats over those hours (dotted line); B) Average recorded wing pumping events per hour of observation for C. n. lincolniana, C. fulgida, and C. circumpicta (bars on graph), and soil surface temperature of the salt flats (dotted line) over those hours; and C) Average recorded flight events per hour of observation for C. n. lincolniana, C. togata, and C. circumpicta and surface temperature of the salt flats over those hours. PeerJ reviewing PDF | (v2013:07:669:1:0:NEW 24 Aug 2013) R ev ie w in g M an us cr ip t PeerJ reviewing PDF | (v2013:07:669:1:0:NEW 24 Aug 2013) R ev ie w in g M an us cr ip t",
    "v2_text": "abstract : How behavioral patterns are related to niche partitioning is an important question in understanding how closely related species within ecological communities function. Behavioral niche partitioning associated with thermoregulation is well documented in tiger beetles as a group. Co-occurring species of salt flat tiger beetles have adapted many thermoregulatory behaviors to cope with this harsh ecosystem. On first examination these beetles appear to occur in overlapping microhabitats and therefore compete for resources. To determine if behavioral niche partitioning is allowing multiple species to occur within the same harsh salt flat ecosystem we observed Cicindela nevadica lincolniana, Cicindela circumpicta, Cicindela fulgida, and Cicindela togata between 8:00 hours and 21:00 hours and recorded all behaviors related to thermoregulation using a digital voice recorder. Results of this study strongly indicate that competition among these species for resources has been reduced by the adaptation of different thermoregulatory behaviors such as spending time in shallow water, avoiding the sun during the hottest parts of the day, and by positioning their body against or away from the soil. The endangered C. n. lincolniana appears to rely most heavily on the shallow water of seeps for their diurnal foraging behavior (potentially limiting their foraging habitat), but with the advantage of allowing foraging during the hottest times of the day when potential competitors are less frequent. Ironically, this association also may help explain C. n. lincolniana\u2018s susceptibility to extinction: beyond the loss of saline wetlands generally, limited seeps and pools even within remaining saline habitat may represent a further habitat limitation within an already limited habitat. 3 4 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 PeerJ reviewing PDF | (v2013:07:669:0:1:NEW 23 Jul 2013) R ev ie w in g M an us cr ip t 3 p values for mann-whitney are estimated (not exact) because of tied ranks. species differences (within : morning or afternoon/evening) were determined by Kruskal-Wallis Test through non-parametric ANOVA (K-W test statistic corrected for ties and P determined from chi-square distribution). Significant species comparisons were determined by Dunn\u2019s Multiple Comparisons Test (only results with P < 0.05 are shown.) PeerJ reviewing PDF | (v2013:07:669:0:1:NEW 23 Jul 2013) R ev ie w in g M an us cr ip t Table 2. Comparison of proportion of time spent on dry surfaces by C. circumpicta, C. fulgida, C. n. lincolniana , and C. togata. Morning and afternoon/evening differences across species were evaluated with a Mann-Whitney test. P values for Mann-Whitney are estimated (not exact) because of tied ranks. Species differences (within morning or afternoon/evening) were determined by Kruskal-Wallis Test through non-parametric ANOVA (K-W test statistic corrected for ties and P determined from chi-square distribution). Significant species comparisons were determined by Dunn\u2019s Multiple Comparisons Test (only results with P < 0.05 are shown.) Proportion of Time on Dry Substrate 8:00-21:00 M-W U P>F Comparison: 8:00-11:00 vs. 11:00-21:00 1514.0 = 0.0255 Times n Mean sd 8:00-11:00 28 0.14 0.33 11:00-21:00 139 0.69 0.29 8:00-11:00 K-W (df = 3) P>X2 Comparison: species x species 0.7793 ns Species n Mean sd C. circumpicta 7 0.14 0.37 C. fulgida 7 0.14 0.37 C. n. lincolniana 11 0.09 0.30 C. togata 3 0.33 0.57 11:00-21:00 K-W (df = 3) P>X2 Comparison: species x species 42.042 < 0.0001 C. circumpicta vs. C. n. lincolniana < 0.001 C. circumpicta vs. C. togata < 0.05 C. fulgida vs. C. n. lincolniana < 0.01 C. fulgida vs. C. togata < 0.01 C. n. lincolniana vs. C. togata < 0.001 Species n Mean sd C. circumpicta 41 0.46 0.48 C. fulgida 34 0.38 0.49 C. n. lincolniana 50 0.04 0.20 C. togata 14 0.62 0.34 PeerJ reviewing PDF | (v2013:07:669:0:1:NEW 23 Jul 2013) R ev ie w in g M an us cr ip t Morning and afternoon/evening differences across species were evaluated with a Mann-Whitney test. morning or afternoon/evening) were determined by Kruskal-Wallis Test through non-parametric ANOVA (K-W test statistic corrected for ties and P determined from chi-square distribution). Significant species comparisons were determined by Dunn\u2019s Multiple Comparisons Test (only results with P < 0.05 are shown.) PeerJ reviewing PDF | (v2013:07:669:0:1:NEW 23 Jul 2013) R ev ie w in g M an us cr ip t Table 3. Comparison of proportion of time spent on mud by C. circumpicta, C. fulgida, C. n. lincolniana , and C. togata. Morning and afternoon/evening differences across species were evaluated with a Mann-Whitney test. P values for Mann-Whitney are estimated (not exact) because of tied ranks. Species differences (within morning or afternoon/evening) were determined by Kruskal-Wallis Test through non-parametric ANOVA (K-W test statistic corrected for ties and P determined from chi-square distribution). Significant species comparisons were determined by Dunn\u2019s Multiple Comparisons Test (only results with P < 0.05 are shown.) Proportion of Time on Mud 8:00-21:00 M-W U P>F Comparison: 8:00-11:00 vs. 11:00-21:00 1645.5 ns Times n Mean sd 8:00-11:00 28 0.70 0.41 11:00-21:00 139 0.58 0.45 8:00-11:00 K-W (df = 3) P>X2 Comparison: species x species 5.900 ns Species n Mean sd C. circumpicta 7 0.85 0.38 C. fulgida 7 0.81 0.38 C. n. lincolniana 11 0.86 0.42 C. togata 3 0.67 0.58 11:00-21:00 K-W (df = 3) P>X2 Comparison: species x species 16.717 = 0.0008 C. circumpicta vs. C. togata < 0.05 C. fulgida vs. C. togata < 0.01 C. n. lincolniana vs. C. togata < 0.001 Species n Mean sd C. circumpicta 41 0.54 0.48 C. fulgida 34 0.61 0.49 C. n. lincolniana 50 0.72 0.35 C. togata 14 0.13 0.34 PeerJ reviewing PDF | (v2013:07:669:0:1:NEW 23 Jul 2013) R ev ie w in g M an us cr ip t Morning and afternoon/evening differences across species were evaluated with a Mann-Whitney test. morning or afternoon/evening) were determined by Kruskal-Wallis Test through non-parametric ANOVA (K-W test statistic corrected for ties and P determined from chi-square distribution). Significant species comparisons were determined by Dunn\u2019s Multiple Comparisons Test (only results with P < 0.05 are shown.) PeerJ reviewing PDF | (v2013:07:669:0:1:NEW 23 Jul 2013) R ev ie w in g M an us cr ip t Table 4. Comparison of proportion of time spent on water by C. circumpicta, C. fulgida, C. n. lincolniana , and C. togata. Morning and afternoon/evening differences across species were evaluated with a Mann-Whitney test. P values for Mann-Whitney are estimated (not exact) because of tied ranks. Species differences (within morning or afternoon/evening) were determined by Kruskal-Wallis Test through non-parametric ANOVA (K-W test statistic corrected for ties and P determined from chi-square distribution). Significant species comparisons were determined by Dunn\u2019s Multiple Comparisons Test (only results with P < 0.05 are shown.) Proportion of Time on Water 8:00-21:00 M-W U P>F Comparison: 8:00-11:00 vs. 11:00-21:00 1703.0 ns Times n Mean sd 8:00-11:00 28 0.15 0.30 11:00-21:00 139 0.08 0.22 8:00-11:00 K-W (df = 3) P>X2 Comparison: species x species 13.274 = 0.0041 C. circumpicta vs. C. n. lincolniana < 0.05 Species n Mean sd C. circumpicta 7 0 0 C. fulgida 7 0.05 0.12 C. n. lincolniana 11 0.36 0.40 C. togata 3 0 0 11:00-21:00 K-W (df = 3) P>X2 Comparison: species x species 44.754 < 0.0001 C. n. lincolniana vs. C. circumpicta < 0.001 C. n. lincolniana vs. C. fulgida < 0.001 C. n. lincolniana < 0.001 Species n Mean sd C. circumpicta 41 0 0 C. fulgida 34 0 0.03 C. n. lincolniana 50 0.23 0.32 C. togata 14 0 0 PeerJ reviewing PDF | (v2013:07:669:0:1:NEW 23 Jul 2013) R ev ie w in g M an us cr ip t Significant differences within an event were determined by Kruskal-Wallis Test through non-parametric ANOVA (K-W test statistic corrected for ties and P determined from chi-square distribution, df = 3). Significant species comparisons were determined by Dunn\u2019s Multiple Comparisons Test (only results with P < 0.05 are shown). PeerJ reviewing PDF | (v2013:07:669:0:1:NEW 23 Jul 2013) R ev ie w in g M an us cr ip t Table 5. Means and standard deviations (sd) of total behavioral events per hour averaged daily (11:00-21:00 for C. circumpicta, C. fulgida, C. n. lincolniana, and C. togata. Significant differences within an event were determined by Kruskal-Wallis Test through non-parametric ANOVA (K-W test statistic corrected for ties and P determined from chi-square distribution, df = 3). Significant species comparisons were determined by Dunn\u2019s Multiple Comparisons Test (only results with P < 0.05 are shown). Abdomen Dipping Mandible Dipping Wing Pumping Flying Species n mean sd mean sd mean sd mean sd C. circumpicta 41 0 0 5.4 10.3 4.0 4.8 0.20 0.46 C. fulgida 34 0 0 2.5 4.2 5.2 5.4 0.59 1.02 C. n. lincolniana 50 0.24 1.2 75.8 99.6 3.9 4.4 0.10 0.30 C. t gata 14 0 0 5.8 9.7 3.9 3.5 0.57 1.16.5 Comparison K-W P> X2 K-W P> X2 K-W P> X2 K-W P> X2 - - 55.50 <0.0001 0.626 ns 9.807 0.02 C. n. lincolniana vs. C. circumpicta < 0.001 C. n. lincolniana vs. C. fulgida < 0.001 < 0.05 C. n. lincolniana vs. C. togata < 0.01 PeerJ reviewing PDF | (v2013:07:669:0:1:NEW 23 Jul 2013) R ev ie w in g M an us cr ip t Figure 1 Average mandible dips, wing pumps, and flight events per hour. Average salt flat temperatures by hour. Temperatures were recorded on the salt flats where observations were made for adult tiger beetles. Temperatures were recorded one meter above the soil surface to determine ambient temperature, one cm above the soil surface to determine the air temperature the subjects were experiencing, and at the soil surface. PeerJ reviewing PDF | (v2013:07:669:0:1:NEW 23 Jul 2013) R ev ie w in g M an us cr ip t Figure 2 Time spent in sun or shade by tiger beetle species. Proportion of time spent in the sun or the shade between 8:00 and 21:00 hours (bars on graph) and soil surface temperature of the salt flats (dotted line) over those hours for four species of salt flat tiger beetle: a) C. circumpicta, b) C. n. lincolniana, c) C. fulgida, and d) C. togata. PeerJ reviewing PDF | (v2013:07:669:0:1:NEW 23 Jul 2013) R ev ie w in g M an us cr ip t Figure 3 Time spent on different substrates by tiger beetle species. Proportion of time spent on wet soil (mud), dry soil, and in shallow water between 8:00 and 21:00 hours (bars on graph) and soil surface temperature of the salt flats (dotted line) over those hours for four species of salt flat tiger beetle: a) C. circumpicta, b) C. n. lincolniana, c) C. fulgida, and d) C. togata. PeerJ reviewing PDF | (v2013:07:669:0:1:NEW 23 Jul 2013) R ev ie w in g M an us cr ip t Figure 4 Time spent engaging in thermoregulatory behavior. Proportion of time spent in four distinct behaviors related to thermoregulation between 8:00 and 21:00 hours (bars on graph), and soil surface temperature of the salt flats (dotted line) over those hours for four species of salt flat tiger beetle: a) C. circumpicta, b) C. n. lincolniana, c) C. fulgida, and d) C. togata. PeerJ reviewing PDF | (v2013:07:669:0:1:NEW 23 Jul 2013) R ev ie w in g M an us cr ip t Figure 5 Average mandible dips, wing pumps, and flight events per hour. A) Average recorded mandible dipping events per hour of observation for C. n. lincolniana and C. circumpicta (bars on graph), and soil surface temperature of the salt flats over those hours (dotted line); B) Average recorded wing pumping events per hour of observation for C. n. lincolniana, C. fulgida, and C. circumpicta (bars on graph), and soil surface temperature of the salt flats (dotted line) over those hours; and C) Average recorded flight events per hour of observation for C. n. lincolniana, C. togata, and C. circumpicta and surface temperature of the salt flats over those hours. PeerJ reviewing PDF | (v2013:07:669:0:1:NEW 23 Jul 2013) R ev ie w in g M an us cr ip t PeerJ reviewing PDF | (v2013:07:669:0:1:NEW 23 Jul 2013) R ev ie w in g M an us cr ip t",
    "url": "https://peerj.com/articles/170/reviews/",
    "review_1": "Andrew Farke \u00b7 Sep 5, 2013 \u00b7 Academic Editor\nACCEPT\nThank you for your quick attention and flexibility on the last round of comments!",
    "review_2": "Andrew Farke \u00b7 Sep 2, 2013 \u00b7 Academic Editor\nMINOR REVISIONS\n1) I note that the museum abbreviation \"NTM\" is not defined in the text (it is my fault for not catching it earlier!). I am assuming this refers to \"Museums and Art Galleries of the Northern Territory,\" but it should be explicitly defined so it is easy for other researchers to know where the holotype is located.\n\n2) In the previous version, I had requested some additional measurements for elements if possible. This was not incorporated into the manuscript, and not referenced in the rebuttal letter. If the specimens are not easily accessible, the manuscript can go as is, but otherwise some basic data (e.g., length along sutural surfaces) for a few complete elements (e.g. NTM P5370, P5364, P5374) would be important. I note that the width of NTM P5369 is included still from the original version.\n\nOnce these final issues are addressed, I should be able to issue a final decision in very short order.",
    "review_3": "Andrew Farke \u00b7 Jul 10, 2013 \u00b7 Academic Editor\nMINOR REVISIONS\nThe reviewers were uniformly positive about your paper, and I agree with their assessment. Only two specific changes are needed, based on the reviewer comments as well as my own reading of the paper:\n\n1) Please update the nomenclature per the suggestions of Reviewer 2.\n\n2) Regarding the purported bite marks, please provide a more detailed description, and also consider the possibility that they may be non-traumatic lesions as described elsewhere in the literature (detailed below). Alternatively, if you are not satisfied with an identification of these features as bite marks in the end, you may consider removing this section of the paper. In my opinion, the manuscript would not be harmed by doing so.\n\nOTHER COMMENTS FROM THE EDITOR:\n- Please consider including measurements (lengths, widths, thicknesses) for all complete elements within the description.\n\n- Could you include just a little more description of the purported tooth marks? Size, spacing, morphology, etc.? A recent paper by Boyd et al. (2013) discussed identification of feeding traces from crocodilians in some detail. Are there signs of genuine bone breakage/indentation? Or could these markings represent the random pits found in many extant turtle shells, even from geographic areas without large and toothy aquatic predators (see Rothschild et al. 2013 for a discussion)? Is Baru the only crocodilian known from the formation? In short, I am not entirely convinced that the markings you describe are necessarily bite marks, at least as presented in the text. Because this is such a minor part of the text, you may wish to just delete it.\n\nCITATIONS\nBoyd CA, Drumheller SK, Gates TA (2013) Crocodyliform Feeding Traces on Juvenile Ornithischian Dinosaurs from the Upper Cretaceous (Campanian) Kaiparowits Formation, Utah. PLoS ONE 8(2): e57605. doi:10.1371/journal.pone.0057605\n\nRothschild, BM, H-P Schultze, R. Pellegrini. 2013. Osseous and Other Hard Tissue Pathologies in Turtles and Abnormalities of Mineral Deposition. In: Morphology and Evolution of Turtles, pp. 501-534.",
    "review_4": "Mark Hutchinson \u00b7 Jul 10, 2013\nBasic reporting\nNo Comments\nExperimental design\nNo comments\nValidity of the findings\nNo comments\nAdditional comments\nA welcome review of the knowledge that has accumulated to date of the fossil history of this genus of turtles, and one that adds several characters that will assiste future workers on the group.\nCite this review as\nHutchinson MN (2013) Peer Review #1 of \"A new species of long-necked turtle (Pleurodira: Chelidae: Chelodina) from the late Miocene Alcoota Local Fauna, Northern Territory, Australia (v0.1)\". PeerJ https://doi.org/10.7287/peerj.170v0.1/reviews/1",
    "pdf_1": "https://peerj.com/articles/170v0.3/submission",
    "pdf_2": "https://peerj.com/articles/170v0.2/submission",
    "review_5": "Scott Thomson \u00b7 Jun 21, 2013\nBasic reporting\nNo Comments\nExperimental design\nNo Comments\nValidity of the findings\nNo Comments\nAdditional comments\nI have enjoyed this paper and extend my congratulations on defining this species. I need to make a couple of corrections on the nomenclature. I note you have largely followed myself and Arthur Georges (2010) on this and will admit that our nomenclature for the Chelidae was slightly wrong. This has been published so I will summarize what was wrong and give you the relevant references.\n\nThe higher order nomenclature of the Chelidae was originally proposed by Baur in 1893. I recently discovered this myself and hence Georges et al. 1998 cannot have credit for it. In the most recent IUCN checklist (van Dijk et al., 2012) the annotations for the Chelidae correct the nomenclature. I suggest you adjust your Systematic Palaeontology section, lines 14 and 15, to be in line with the findings of that paper. Throughout your introduction you will also need to update and reword your discussions of subfamily Chelodininae to ensure the name is referred to Baur (1893). It is still correct that the reciprocal monophyly was proposed by Georges et al., 1998 and they did suggest the use of subfamilies. They just did not know about the previous attempt to do this by Baur, 1893.\n\nBelow are the higher orders with correct citations and full citations for Gray 1825 and Baur 1893. I also include the citation for the 2012 checklist where the nomenclature was determined and a link to the pdf of that paper.\n\nChelidae Gray 1825\nChelinae Gray 1825\nChelodininae Baur 1893\nHydromedusinae Baur 1893\n\nBaur, Georg. 1893. Notes on the classification and taxonomy of the Testudinata. Proceedings of the American Philosophical Society 31:210\u2013225.\nGray, John Edward. 1825. A synopsis of the genera of reptiles and amphibia, with a description of some new species. Annals of Philosophy (2)10:193\u2013217.\nvan Dijk , P.P., Iverson, J.B., Shaffer, H.B., Bour, R., and Rhodin, A.G.J. 2012. Turtles of the world, 2012 update: annotated checklist of taxonomy, synonymy, distribution, and conservation status. Chelonian Research Monographs No. 5, pp. 000.243\u2013000.328.\n\nChecklist available here:\nhttp://www.iucn-tftsg.org/wp-content/uploads/file/Accounts/crm_5_000_checklist_v5_2012.pdf\n\nI do think you need to make these nomenclatural corrections, sorry that my 2010 paper also had it slightly wrong so I blame myself for that. Apart from that I think the paper should be accepted.\n\nJust for your information, and this is unpublished, when I was at Naracourte many years ago there was a relatively complete shell of C. (Chelodina) probably longicollis in the collection at the University. From the Naracourte caves. As far as I am aware it has never been published though.\n\nFeel free to email me if you would like to see the Baur, 1893 paper, I have a pdf of it.\nCite this review as\nThomson SA (2013) Peer Review #2 of \"A new species of long-necked turtle (Pleurodira: Chelidae: Chelodina) from the late Miocene Alcoota Local Fauna, Northern Territory, Australia (v0.1)\". PeerJ https://doi.org/10.7287/peerj.170v0.1/reviews/2",
    "pdf_3": "https://peerj.com/articles/170v0.1/submission",
    "all_reviews": "Review 1: Andrew Farke \u00b7 Sep 5, 2013 \u00b7 Academic Editor\nACCEPT\nThank you for your quick attention and flexibility on the last round of comments!\nReview 2: Andrew Farke \u00b7 Sep 2, 2013 \u00b7 Academic Editor\nMINOR REVISIONS\n1) I note that the museum abbreviation \"NTM\" is not defined in the text (it is my fault for not catching it earlier!). I am assuming this refers to \"Museums and Art Galleries of the Northern Territory,\" but it should be explicitly defined so it is easy for other researchers to know where the holotype is located.\n\n2) In the previous version, I had requested some additional measurements for elements if possible. This was not incorporated into the manuscript, and not referenced in the rebuttal letter. If the specimens are not easily accessible, the manuscript can go as is, but otherwise some basic data (e.g., length along sutural surfaces) for a few complete elements (e.g. NTM P5370, P5364, P5374) would be important. I note that the width of NTM P5369 is included still from the original version.\n\nOnce these final issues are addressed, I should be able to issue a final decision in very short order.\nReview 3: Andrew Farke \u00b7 Jul 10, 2013 \u00b7 Academic Editor\nMINOR REVISIONS\nThe reviewers were uniformly positive about your paper, and I agree with their assessment. Only two specific changes are needed, based on the reviewer comments as well as my own reading of the paper:\n\n1) Please update the nomenclature per the suggestions of Reviewer 2.\n\n2) Regarding the purported bite marks, please provide a more detailed description, and also consider the possibility that they may be non-traumatic lesions as described elsewhere in the literature (detailed below). Alternatively, if you are not satisfied with an identification of these features as bite marks in the end, you may consider removing this section of the paper. In my opinion, the manuscript would not be harmed by doing so.\n\nOTHER COMMENTS FROM THE EDITOR:\n- Please consider including measurements (lengths, widths, thicknesses) for all complete elements within the description.\n\n- Could you include just a little more description of the purported tooth marks? Size, spacing, morphology, etc.? A recent paper by Boyd et al. (2013) discussed identification of feeding traces from crocodilians in some detail. Are there signs of genuine bone breakage/indentation? Or could these markings represent the random pits found in many extant turtle shells, even from geographic areas without large and toothy aquatic predators (see Rothschild et al. 2013 for a discussion)? Is Baru the only crocodilian known from the formation? In short, I am not entirely convinced that the markings you describe are necessarily bite marks, at least as presented in the text. Because this is such a minor part of the text, you may wish to just delete it.\n\nCITATIONS\nBoyd CA, Drumheller SK, Gates TA (2013) Crocodyliform Feeding Traces on Juvenile Ornithischian Dinosaurs from the Upper Cretaceous (Campanian) Kaiparowits Formation, Utah. PLoS ONE 8(2): e57605. doi:10.1371/journal.pone.0057605\n\nRothschild, BM, H-P Schultze, R. Pellegrini. 2013. Osseous and Other Hard Tissue Pathologies in Turtles and Abnormalities of Mineral Deposition. In: Morphology and Evolution of Turtles, pp. 501-534.\nReview 4: Mark Hutchinson \u00b7 Jul 10, 2013\nBasic reporting\nNo Comments\nExperimental design\nNo comments\nValidity of the findings\nNo comments\nAdditional comments\nA welcome review of the knowledge that has accumulated to date of the fossil history of this genus of turtles, and one that adds several characters that will assiste future workers on the group.\nCite this review as\nHutchinson MN (2013) Peer Review #1 of \"A new species of long-necked turtle (Pleurodira: Chelidae: Chelodina) from the late Miocene Alcoota Local Fauna, Northern Territory, Australia (v0.1)\". PeerJ https://doi.org/10.7287/peerj.170v0.1/reviews/1\nReview 5: Scott Thomson \u00b7 Jun 21, 2013\nBasic reporting\nNo Comments\nExperimental design\nNo Comments\nValidity of the findings\nNo Comments\nAdditional comments\nI have enjoyed this paper and extend my congratulations on defining this species. I need to make a couple of corrections on the nomenclature. I note you have largely followed myself and Arthur Georges (2010) on this and will admit that our nomenclature for the Chelidae was slightly wrong. This has been published so I will summarize what was wrong and give you the relevant references.\n\nThe higher order nomenclature of the Chelidae was originally proposed by Baur in 1893. I recently discovered this myself and hence Georges et al. 1998 cannot have credit for it. In the most recent IUCN checklist (van Dijk et al., 2012) the annotations for the Chelidae correct the nomenclature. I suggest you adjust your Systematic Palaeontology section, lines 14 and 15, to be in line with the findings of that paper. Throughout your introduction you will also need to update and reword your discussions of subfamily Chelodininae to ensure the name is referred to Baur (1893). It is still correct that the reciprocal monophyly was proposed by Georges et al., 1998 and they did suggest the use of subfamilies. They just did not know about the previous attempt to do this by Baur, 1893.\n\nBelow are the higher orders with correct citations and full citations for Gray 1825 and Baur 1893. I also include the citation for the 2012 checklist where the nomenclature was determined and a link to the pdf of that paper.\n\nChelidae Gray 1825\nChelinae Gray 1825\nChelodininae Baur 1893\nHydromedusinae Baur 1893\n\nBaur, Georg. 1893. Notes on the classification and taxonomy of the Testudinata. Proceedings of the American Philosophical Society 31:210\u2013225.\nGray, John Edward. 1825. A synopsis of the genera of reptiles and amphibia, with a description of some new species. Annals of Philosophy (2)10:193\u2013217.\nvan Dijk , P.P., Iverson, J.B., Shaffer, H.B., Bour, R., and Rhodin, A.G.J. 2012. Turtles of the world, 2012 update: annotated checklist of taxonomy, synonymy, distribution, and conservation status. Chelonian Research Monographs No. 5, pp. 000.243\u2013000.328.\n\nChecklist available here:\nhttp://www.iucn-tftsg.org/wp-content/uploads/file/Accounts/crm_5_000_checklist_v5_2012.pdf\n\nI do think you need to make these nomenclatural corrections, sorry that my 2010 paper also had it slightly wrong so I blame myself for that. Apart from that I think the paper should be accepted.\n\nJust for your information, and this is unpublished, when I was at Naracourte many years ago there was a relatively complete shell of C. (Chelodina) probably longicollis in the collection at the University. From the Naracourte caves. As far as I am aware it has never been published though.\n\nFeel free to email me if you would like to see the Baur, 1893 paper, I have a pdf of it.\nCite this review as\nThomson SA (2013) Peer Review #2 of \"A new species of long-necked turtle (Pleurodira: Chelidae: Chelodina) from the late Miocene Alcoota Local Fauna, Northern Territory, Australia (v0.1)\". PeerJ https://doi.org/10.7287/peerj.170v0.1/reviews/2\nReview 6: \n",
    "LLM_extracted_review": "['Review 1: Thank you for your quick attention and flexibility on the last round of comments!\\n\\nReview 2: \\n1) The museum abbreviation \"NTM\" is not defined in the text; it should be explicitly defined for clarity.\\n2) Additional measurements for elements were not incorporated into the manuscript as previously requested. Basic data for a few complete elements would be important if accessible.\\n\\nReview 3: \\n1) Update the nomenclature per the suggestions of Reviewer 2.\\n2) Provide a more detailed description of the purported bite marks and consider the possibility that they may be non-traumatic lesions. Alternatively, consider removing this section if not satisfied with the identification.\\n\\nReview 4: A welcome review of the knowledge that has accumulated to date of the fossil history of this genus of turtles, adding several characters that will assist future workers on the group.\\n\\nReview 5: Corrections on the nomenclature are needed. The higher order nomenclature of the Chelidae was originally proposed by Baur in 1893, and the paper should be adjusted to reflect this. The discussions of subfamily Chelodininae should also be updated to ensure proper attribution to Baur (1893).']"
}