Caudal displays that lure or divert the attention of prey are well documented in legless squamates that use sit-and-wait foraging. By contrast, empirical evidence that caudal displays serve to distract prey is lacking in legged lizards. Preliminary observations suggested that juvenile Collared Lizards (Crotaphytus collaris) may give caudal displays when stalking arthropods. Therefore, we conducted field experiments involving introduction of tethered grasshoppers to test whether free-ranging lizards performed more caudal displays when they were stalking prey. Results revealed that lizards performed tail displays more frequently and longer when they were stalking than when not stalking tethered prey. Our results appear to be the first experimental support for the hypothesis that legged lizards use caudal displays when stalking prey, perhaps to distract the attention of prey away from the mouth. Combined with other published results, we demonstrate that caudal displays play a role in both foraging and predator avoidance in juvenile Collared Lizards.

Robust methods for estimating abundance of wetland-breeding amphibian species, such as mark–recapture, are often resource intensive. This limits our ability to study the processes that influence species abundance. Alternatively, more efficient sampling methods, such as indices based on visual encounter surveys (VES) (e.g., egg masses), may be biased by variability in detection probabilities and species biology (e.g., no. of egg masses per female). We combine data sources (i.e., VES and capture–mark–recapture) to provide an efficient technique for monitoring wetland-breeding amphibians. Our study focuses on understanding factors that determine local abundance of Spotted Salamanders, Ambystoma maculatum, in Pennsylvania. We first estimated abundance for a subset of wetlands using single-season, capture–mark–recapture data and then verified egg-mass counts collected from a wider network of wetlands as an unbiased index of abundance. We found a strong correlation between estimated adult abundance and estimated egg-mass abundance with an estimated ratio of one egg mass per adult per breeding effort. We next determined the factors that best explained variation in estimated A. maculatum egg-mass abundance and consequently, adult abundance among sites. Our “best-fit” model included effects for wetland hydroperiod and quadratic effects of mean water temperature. We also report positive, but weak, association with two co-occurring amphibian species, Jefferson Salamanders, A. jeffersonianum and Wood Frogs, Lithobates sylvaticus. We demonstrate how combining sampling approaches can provide efficient abundance estimates in wetland ecosystems. In particular, positive co-occurrence among species indicates shared habitat preferences that may enable us to predict the presence of difficult-to-detect species using only VES.

Color polymorphism is common in many species, and color morph frequency is affected by differences in ecological and evolutionary pressures on each color morph. Plethodon cinereus, the Red-Backed Salamander, has two common color morphs, striped and unstriped, that vary in frequency among populations. Plethodon cinereus color morphs differ in their escape behaviors when exposed to predators and in their tail autotomization rates; this may result from differential predation. Although these previous studies indirectly implicated differential predation, we directly tested the hypothesis that color morphs differed in survival and whether one morph was depredated at a higher rate. We determined the survival of each color morph over 3 yr with the use of mark–recapture data. We first compared frequencies of color morphs in juveniles and adults, and then estimated whether color morphs had different survival rates with the statistical program MARK. We found that frequency of striped salamanders was lower in adults than in juveniles, implying that fewer striped individuals survived to adulthood. In addition, color and age best explained survival probability during spring, but not fall, seasons. To test the effects of color morph on predation experimentally, we used clay models to determine the effects of avian and mammalian predators. We found more attacks on striped clay models by avian predators compared to the unstriped models, but we found no difference in attacks by mammals. Overall, these results support the hypothesis that there is differential predation in P. cinereus, with more predation on, and lower survival in, the striped morph.

Small populations resulting from the impacts of habitat fragmentation are prone to increased risks of extinction because of a lack of population connectivity. Roads increase habitat fragmentation, but properly managed roadsides may be able to function as wildlife corridors. Here we use radiotelemetry to observe movement patterns of Gopher Tortoises (Gopherus polyphemus) along potential roadside corridors at the John F. Kennedy Space Center (KSC) in Florida, USA, to determine if tortoises use roadsides as movement pathways between larger habitat patches or as residential habitat. Additionally, we translocated tortoises to study the feasibility of roadsides to function as movement corridors. We found that roadsides are not used as a movement pathway but rather as an apparent long-term residential habitat. Only one tortoise was observed exiting the roadside corridor, and minimum convex polygon (MCP) home range sizes and distances traveled remain similar to those exhibited by tortoises in larger habitat patches. Following translocation, we observed a failure to return home, either by direct paths or by corridor use, for all but one tortoise. Instead, most tortoises remained along roadsides after only a brief period of exploration. Overall, we find that roadsides act as independent, residential habitat instead of as a movement corridor. Future studies should focus on understanding the actual suitability of roadsides, as they may function as ecological traps given their attractiveness but high risk of mortality. While we urge caution, current management should treat roadsides as residential locations for Gopher Tortoises and focus on reducing road mortality.

Both phylogenetic and environmental forces can drive ecological variation across the geographic distribution of squamates. We compared microhabitat use, temperature, diet, and reproductive data among three Tropidurus hispidus and Cnemidophorus ocellifer populations (Caatinga; Atlantic Forest; and Restinga coastal environments) and tested whether these characteristics varied along that distribution. Tropidurus hispidus was found primarily on human-made structures or tree trunks, and C. ocellifer was more often found on open ground or associated with vegetation. Substrate temperature was the most influential factor on body temperature, and no difference in body temperatures was observed among populations. Overall, diet composition was similar among populations; however, some differences were observed for main prey categories for C. ocellifer. Mean clutch size (T. hispidus = 6 eggs; C. ocellifer = 2 eggs) did not significantly differ among populations. Tropidurus hispidus seems to avoid reproducing during the dry season, exhibiting seasonal reproduction in the Caatinga and continuous reproduction in the Restinga and Atlantic Forest. Cnemidophorus ocellifer exhibited seasonal reproduction in the Tabuleiro region of the Atlantic Forest and continuous reproduction in the other two environments. Microhabitat use, diet, and reproductive cycle varied among populations of each species, whereas body temperature and clutch size remained unaltered, showing the importance of both ecological and historical factors along their geographic range.

Predators often evolve specialized behaviors to feed on dangerous prey. Centipedes are widely documented in the diet of viperid snakes, but the behaviors snakes use to consume these dangerous prey have been reported only anecdotally. To determine how prey type influenced snake foraging behaviors, we ran laboratory predation trials using 29 field-captured Pigmy Rattlesnakes (Sistrurus miliarius) with centipedes (Scolopendra viridis) and skinks (Scincella lateralis). In skink trials, Pigmy Rattlesnakes were significantly more likely to engage in sit-and-wait predation than in centipede trials where active pursuit of prey was frequent. Centipedes were struck by snakes in significantly more trials than skinks and the mean length of strikes directed at centipedes was significantly shorter than for the strikes directed at skinks. Strike latency was significantly lower for centipedes than for skinks. The location on the prey's body where the strike was directed did not differ in skink and centipede trials. The mean time from snake strike to last prey locomotion and to prey ingestion were both significantly longer for centipedes. Pigmy Rattlesnakes exhibited several behaviors in centipede trials, including head elevation when approaching prey, that were never observed in skink trials. Centipedes occasionally struck rattlesnakes, but the snakes did not have any apparent injuries. Pigmy Rattlesnakes displayed plasticity in foraging behaviors to effectively prey on centipedes. The implications of centipede consumption in vipers merits increased attention given its occurrence in dozens of species.

Long-term interactions often shape predator–prey relationships in the form of a co-evolutionary “arms race.” The arrival of nonnative species may disrupt these relationships by introducing novel behaviors that shift interactions in favor of one of the participants. Here we investigated the response of an imperiled native predator, the Eastern Hellbender (Cryptobranchus alleganiensis), to nonnative and native crayfish prey. Crayfish constitute an important prey item for hellbenders, and in the northern portion of its range where this research was conducted, the nonnative Rusty Crayfish (Orconectes rusticus) has become the dominant crayfish. The objective of this study was to determine prey choice and feeding success of hellbenders presented with native (Allegheny Crayfish; Orconectes obscurus) and nonnative (Rusty Crayfish) crayfish prey. We tested hellbender chemoreception in discriminating between the native and nonnative prey, analyzed behavioral interactions between hellbenders and crayfish during video-recorded trials, and assessed hellbender selectivity of crayfish during overnight feeding trials. Hellbenders were able to discriminate crayfish odor from controls, showed a preference for the scent of native crayfish over nonnative crayfish, and were more likely to strike at native crayfish than at nonnative crayfish; however, more nonnative crayfish were consumed during overnight feeding trials. This discrepancy apparently resulted from differences in avoidance behavior between the prey species; native crayfish engaged more in predator-avoidance tail-flip responses and climbing retreats than the nonnatives, who tended to “stand their ground.” Accordingly, during biotic invasions, food preferences of native predators may be superseded by antipredator prey behavior.

There are two patterns of gonad differentiation in amphibians, but the role of sex steroids in gonad differentiation is not clear. I studied the role of estrogen in gonadal sex differentiation in the frog Euphlyctis cyanophlyctis with an undifferentiated type of gonad differentiation (testis differentiates through an ovarian phase) using an aromatase inhibitor, formestane (FR). I treated tadpoles with four concentrations of FR (1, 10, 50, and 100 μg/L) during Gosner stages 25–42. Treatment of higher concentrations (50 and 100 μg/L) of FR produced a male-biased sex ratio and inhibited ovary development but not ovarian cavity and meiocytes formation. These results suggest that estrogen may not be involved in early ovarian differentiation and the ovarian phase is important for testis differentiation in E. cyanophlyctis.

American Bullfrogs (Rana catesbeiana) and Green Frogs (Rana clamitans) share ranges and breeding seasons, are ecologically similar, and often occupy the same breeding ponds throughout the summer. Males of both species use vocalizations to defend territories and attract females; however, Bullfrogs have longer calls and call much more frequently than Green Frogs. The calls of the two species overlap in frequency; thus, Bullfrog calls are a likely source of acoustic interference for Green Frogs that could affect their ability to attract females. Nevertheless, in natural settings where these species co-occur, Green Frogs reproduce successfully. This suggests that Green Frogs respond to the calling patterns of Bullfrogs in ways that maximize Green Frog signal-to-noise ratio. We used long-term pond environment recordings and bioacoustics analyzing software to explore the influence of Bullfrog calling patterns on the vocal activity of syntopic Green Frogs. We found both species call most actively within the same seasonal and diel periods. Our results show that Green Frogs avoid overlapping their calls with Bullfrogs more often than expected by chance. Therefore, to avoid Bullfrog call overlap, Green Frogs use the fine-scale behavioral response of placing their calls in silent gaps between the calls of Bullfrogs. This pattern was even more pronounced in interactions between nearest neighbors in which there was no overlap observed between Bullfrogs and their nearest neighbor Green Frog.

Spermatogenesis, the production of sperm, is a fundamental part of the reproductive cycle in vertebrates and warrants detailed study. Reptiles exhibit a hybrid pattern of spermatogenesis that has similarities with both anamniotes and amniotes. Researching this interesting transition will help us better understand vertebrate evolution. To this end, we histologically examined the spermatogenic and testicular cycle of Rough Greensnakes (Opheodrys aestivus) from Arkansas. We hypothesized that spermatogenesis in Rough Greensnakes would follow the different spermatogenic stages found in previously published studies on temperate snakes. In addition, we hypothesized that both season and seminiferous tubule diameter would have a significant effect on seminiferous tubule epithelial height. Finally, we hypothesized that Rough Greensnakes would exhibit postnuptial spermatogenesis. We constructed a cell wheel illustrating the chronological development of all germ cell stages for this species and measured seminiferous tubule diameter and seminiferous tubule epithelial height from 22 specimens. Opheodrys aestivus exhibited small seminiferous tubule diameters in spring followed by an increase in summer. By October the lumen was mostly empty of sperm because they had migrated to the vas deferens for winter storage. Seminiferous tubule epithelial height was significantly correlated with seminiferous tubule diameter. Both seminiferous tubule diameter and season significantly affected seminiferous tubule epithelial height. This species can be categorized as having postnuptial spermatogenesis where sperm are produced in the summer after spring mating. Future studies of O. aestivus need to investigate the testicular cycle in other parts of their geographic distribution to see if this monthly pattern is consistent.

Wood Turtles (Glyptemys insculpta) occupy forested streams at midlatitudes in eastern North America and are listed as endangered by the International Union for Conservation of Nature, but few populations have been rigorously studied. We studied a population of Wood Turtles in Michigan for 18 yr, individually marking 260 different turtles (146 females, 88 males, and 26 unsexed juveniles), including 118 turtles that we followed for one or more years using radiotelemetry. We analyzed our encounter data using a Cormack–Jolly–Seber model in Program MARK; and we estimated total population size using a Bayesian integrated population model that combined Horvitz–Thompson estimates of annual population size, mark–recapture estimates of annual survival, and derived estimates of annual recruitment. Annual adult survival was 0.970 ± 0.016 SD and annual recruitment to age 15 (mean age of first capture) was 0.058 ± 0.019 SD. Over the 18-yr study, estimated population size grew from 770 (95% CI 631–928) to 1,196 (95% CI 977–1,444) individuals.

Signaling is an important part of intraspecific and interspecific interactions. Theoretical work examining honest signaling in aposematic species (e.g., those with conspicuous colors and secondary defenses) has focused primarily on discerning the patterns between conspicuousness and defense within populations. Most empirical work, however, has investigated these patterns across populations or species. Here, we test for honest signaling across individuals within a population of the aposematic poison frog, Ranitomeya imitator. We find no evidence that increasing levels of the aposematic signal are correlated with increasing levels of defense in this species, indicating that our study population does not signal in a quantitatively honest manner, but rather that the signal is qualitatively honest. Additionally, we found no evidence that frogs with higher levels of defense behave more boldly as a result of the presumed increased ecological release from predation, an expected outcome in a qualitatively honest system. We discuss our findings in light of the ecology and evolution of R. imitator, and suggest mechanisms that may explain the absence of a relationship between toxicity and the aposematic signal.

Body-size variation in desmognathan salamanders in the southern Appalachian Mountains is coupled with trade-offs among life-history traits that affect growth, survival, and reproduction. Reproductive effort is an important trait that is often measured as the gonadosomatic index (GSI), defined as clutch mass relative to total body mass. I measured GSI as brood mass relative to maternal body mass in two assemblages of Desmognathus in the Cowee and Nantahala mountains of southwestern North Carolina. I also re-evaluated the size–fecundity relationship in the Nantahala Mountain assemblage on the basis of newer data. In addition, I examined the potential trade-off between number and size of offspring in several species in both assemblages. Among species, GSI decreased slightly with increasing body size; the trend is considered a probable effect of decreasing metabolic rate with body size rather than a trade-off with one or another life-history trait. Although both propagule size and number increased with body size among species, the rate of increase in the latter was lower than expected, suggesting a trade-off related to the advantages of larger vs. smaller propagules in larger vs. smaller species. To further assess reproductive traits, I summarized published estimates of key developmental ages in these species. I discuss the results in the context of the correlation between body size and habitat associations in Desmognathus, i.e., the adaptation of larger species to more aquatic (stream) and smaller species to more terrestrial (forest) habitats.

Biological invasions are one of the most serious threats to biodiversity conservation. Although success and impacts of many invaders, particularly ectotherms, are likely to be limited by a combination of climatic and demographic factors, human modifications to the environment can facilitate distributional expansion into otherwise low-quality landscapes. We assessed factors that might promote or preclude population viability of a nonnative ectotherm, Hemidactylus turcicus (Mediterranean House Gecko), within an urban center at the northern periphery of its known North American range. Mediterranean House Geckos are increasingly apparent in the southeastern United States, but their potential for establishment and spread in more temperate regions is less well known. We gathered data using capture–recapture methods and the unique dorsal patterns of individual geckos. Despite a more temperate climate compared to other areas in their introduced range, and refuge temperatures falling below the critical thermal minimum previously documented for other introduced Mediterranean House Gecko populations, geckos survived the winter and reproduced successfully. Cormack–Jolly–Seber open population models did not provide definitive evidence regarding changes in population size over the study period. The tendency for this introduced species to establish populations primarily within urban centers may suggest that negative impacts associated with this northerly expansion are minor. Nonetheless, a high potential for range expansion suggests a need to assess a potentially growing suite of ecosystem interactions.

We describe the first record of a fossil gekkotan from the Late Oligocene Nsungwe Formation in the Rukwa Rift Basin, Tanzania. The specimen consists of an almost complete maxilla containing 23 tooth positions, with 10 teeth still in place. Typical gekkotan features include the tall facial process along with a posteriorly sloping angle, and the presence of unicuspid, pleurodont teeth with large resorption pits. Limited preservation does not allow for a more specific systematic assignment, which is why we refer the specimen to Gekkota incertae sedis. The material represents the second record of a Paleogene gekkotan from Africa and the first one from the central part of the continent.

Bog Turtles (Glyptemys muhlenbergii) are cryptic habitat specialists, requiring spring-fed bogs, fens, and wet meadows, and are among the most imperiled turtles in North America. Despite the sensitive conservation status of this species, data on nesting ecology remain scant. We used radiotelemetry to collect information on the nesting ecology and nest success of Bog Turtles at two sites in Maryland. We had three main objectives: 1) to determine elements of reproductive biology critical to population viability, 2) to investigate rates of nest and egg success, and 3) to compare these variables between two proximate geographic localities. We documented a total of 41 nests across both sites and study years, all between 8 and 22 June of each year. In some cases, turtles used the same nest sites between years, and nests were in moist soil, moss, sedge tussocks, and mats of vegetation. Nesting turtles were typically observed in the late afternoon and evening, between 1557 and 2222 h. Clutch sizes averaged 3.52 ± 1.08 eggs across both sites and years. Nesting success was significantly different between sites, and most nests that did produce surviving hatchlings experienced at least partial depredation before hatching. We stress the importance of collecting site-specific nesting data for this species, and suggest that nest protection may be a useful tool for increasing rates of nest success at some sites.

We describe a new species of Amphisbaena from the Caatinga in the northern region of Bahia, northeastern Brazil. The new taxon is identified mainly by having two precloacal pores, 158–165 body annuli, 12–14 caudal annuli with autotomy on the third and fourth annuli, 14–16 dorsal and 15–16 ventral segments on a midbody annulus, four supralabials, three infralabials, and a postmalar row. Its description increases to 23 the number of species of Amphisbaenia for the Caatinga. Knowledge of worm lizard richness has largely increased in Brazil since the 1990s, especially in the Caatinga and the Cerrado, due mainly to collections in previously unsurveyed areas for environmental impact assessments.

Nós descrevemos uma nova espécie de Amphisbaena da Caatinga na região norte da Bahia, nordeste do Brasil. O novo taxon é identificado principalmente por possuir dois poros pré-cloacais, 158–165 anéis corporais, 12–14 anéis caudais com autotomia no terceiro e quarto anéis, 14–16 segmentos dorsais e 15–16 segmentos ventrais em um anel no meio do corpo, quatro supralabiais, três infralabiais, e uma fileira pós-malar. Sua descrição eleva para 23 o número de espécies de Amphisbaenia para a Caatinga. O conhecimento sobre a riqueza de espécies de cobras-de-duas-cabeças tem aumentado intensamente no Brasil desde a década de 1990, especialmente na Caatinga e no Cerrado, em maior parte devido a coletas em áreas previamente não amostradas para fins de estudos de impacto ambiental.