Pub Date : 2022-12-14DOI: 10.1655/Herpetologica-D-22-00014
Nicole E. Shangi, K. M. Gardner, D. Mennill, S. Doucet
Abstract: Research on anuran parasites often focuses on the description and identification of parasites and demonstrating that parasitic infection can have deleterious effects on the health of amphibians. There is comparatively little research on how parasitism influences evolutionary dynamics such as sexual selection. Here, we explore anuran blood parasites with a focus on parasite-mediated sexual selection. The Hamilton–Zuk hypothesis posits that parasite–host coevolution drives sexual ornamentation of hosts, and that the degree of ornament expression honestly signals heritable parasite resistance. Although the Hamilton–Zuk hypothesis has received support in a number of animal taxa, it has received little attention in amphibians. Neotropical Yellow Toads (Incilius luetkenii) are sexually dichromatic toads with an unusual sexual ornament: males turn from cryptic brown to bright lemon yellow for a very short period during the brief breeding season. In this study, we identify blood parasites in male Neotropical Yellow Toads, and we investigate one component of the Hamilton–Zuk hypothesis by comparing skin color and body condition to blood parasite levels. We found four types of parasites. Apicomplexa and frog erythrocytic virus were the most common, infecting 73% and 46% of toads, respectively, whereas Nematoda and bacteria were found in 27% and 36% of toads, respectively. We found negative relationships between parasites and male color: males infected with fewer Apicomplexa and Nematoda had higher yellow saturation, and males with fewer Nematoda had longer-wavelength hue. In contrast, we found one positive relationship between parasites and male color: males infected with higher levels of frog erythrocytic virus had higher brightness. Our results suggest that parasites may influence sexual traits in this species, but that the relationship is complex. This research contributes to our understanding of amphibian host–parasite coevolution by demonstrating a relationship between parasites and host coloration.
{"title":"Is Color Related to Parasite Load in a Sexually Dichromatic Neotropical Toad?","authors":"Nicole E. Shangi, K. M. Gardner, D. Mennill, S. Doucet","doi":"10.1655/Herpetologica-D-22-00014","DOIUrl":"https://doi.org/10.1655/Herpetologica-D-22-00014","url":null,"abstract":"Abstract: Research on anuran parasites often focuses on the description and identification of parasites and demonstrating that parasitic infection can have deleterious effects on the health of amphibians. There is comparatively little research on how parasitism influences evolutionary dynamics such as sexual selection. Here, we explore anuran blood parasites with a focus on parasite-mediated sexual selection. The Hamilton–Zuk hypothesis posits that parasite–host coevolution drives sexual ornamentation of hosts, and that the degree of ornament expression honestly signals heritable parasite resistance. Although the Hamilton–Zuk hypothesis has received support in a number of animal taxa, it has received little attention in amphibians. Neotropical Yellow Toads (Incilius luetkenii) are sexually dichromatic toads with an unusual sexual ornament: males turn from cryptic brown to bright lemon yellow for a very short period during the brief breeding season. In this study, we identify blood parasites in male Neotropical Yellow Toads, and we investigate one component of the Hamilton–Zuk hypothesis by comparing skin color and body condition to blood parasite levels. We found four types of parasites. Apicomplexa and frog erythrocytic virus were the most common, infecting 73% and 46% of toads, respectively, whereas Nematoda and bacteria were found in 27% and 36% of toads, respectively. We found negative relationships between parasites and male color: males infected with fewer Apicomplexa and Nematoda had higher yellow saturation, and males with fewer Nematoda had longer-wavelength hue. In contrast, we found one positive relationship between parasites and male color: males infected with higher levels of frog erythrocytic virus had higher brightness. Our results suggest that parasites may influence sexual traits in this species, but that the relationship is complex. This research contributes to our understanding of amphibian host–parasite coevolution by demonstrating a relationship between parasites and host coloration.","PeriodicalId":56312,"journal":{"name":"Herpetologica","volume":"78 1","pages":"235 - 243"},"PeriodicalIF":2.4,"publicationDate":"2022-12-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"67431527","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-12-14DOI: 10.1655/0018-0831-78.4.278
League Awards
The Herpetologists’ League congratulates all of the individuals who were evaluated as part of the Graduate Research Award. The winners of the 2022 competition are as follows: Winner.—Brian Tornabene, University of Montana, ‘‘Combining Experiments and Field Surveys to Estimate Comparative Effects Of Energy-Related Saline Wastewaters and Sodium Chloride on Two Amphibian Species.’’ 1 Runner Up.—Kathleen Webster, University of New Mexico, ‘‘More Complex than You’d Skink: Morphological and Molecular Investigation into the Island Biogeography of Flexiseps Skinks in the Comoros Archipelago.’’
{"title":"2022 Winners of the Herpetologists' League Awards","authors":"League Awards","doi":"10.1655/0018-0831-78.4.278","DOIUrl":"https://doi.org/10.1655/0018-0831-78.4.278","url":null,"abstract":"The Herpetologists’ League congratulates all of the individuals who were evaluated as part of the Graduate Research Award. The winners of the 2022 competition are as follows: Winner.—Brian Tornabene, University of Montana, ‘‘Combining Experiments and Field Surveys to Estimate Comparative Effects Of Energy-Related Saline Wastewaters and Sodium Chloride on Two Amphibian Species.’’ 1 Runner Up.—Kathleen Webster, University of New Mexico, ‘‘More Complex than You’d Skink: Morphological and Molecular Investigation into the Island Biogeography of Flexiseps Skinks in the Comoros Archipelago.’’","PeriodicalId":56312,"journal":{"name":"Herpetologica","volume":"78 1","pages":"278 - 278"},"PeriodicalIF":2.4,"publicationDate":"2022-12-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42634436","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-09-06DOI: 10.1655/0018-0831-78.3.223
{"title":"Jones-Lovich Grant in Southwestern HerpetologyCall For Applications","authors":"","doi":"10.1655/0018-0831-78.3.223","DOIUrl":"https://doi.org/10.1655/0018-0831-78.3.223","url":null,"abstract":"","PeriodicalId":56312,"journal":{"name":"Herpetologica","volume":"78 1","pages":"223 - 223"},"PeriodicalIF":2.4,"publicationDate":"2022-09-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46303008","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-09-06DOI: 10.1655/0018-0831-78.3.224
{"title":"Joseph C. Mitchell Grant in HerpetologyCall for Applications","authors":"","doi":"10.1655/0018-0831-78.3.224","DOIUrl":"https://doi.org/10.1655/0018-0831-78.3.224","url":null,"abstract":"","PeriodicalId":56312,"journal":{"name":"Herpetologica","volume":"78 1","pages":"224 - 224"},"PeriodicalIF":2.4,"publicationDate":"2022-09-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44330342","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-09-06DOI: 10.1655/Herpetologica-D-21-00031
Nathalie Jreidini, D. Green
Abstract: Homing abilities have been widely documented in amphibians, but it remains unclear whether individuals have homing tendencies in the absence of motivational cues related to breeding and site fidelity. We tested whether artificial displacement would affect the movement behavior of a nonphilopatric terrestrial amphibian, the Fowler's Toad (Anaxyrus fowleri), within its home range and after its breeding season had ended. We translocated 65 male and female Fowler's Toads from their initial points of capture a total of 104 times over one of three different distances (100 m, 250 m, and 500 m) and compared these toads' subsequent 24-h movements with those of a control group of 43 untranslocated toads. To shield the translocated toads from auditory, visual, and olfactory cues en route, we translocated them in opaque enclosed boxes and performed the experiment in the uniformly unobstructed landscape of the Lake Erie shoreline of Long Point, ON, Canada. We mainly investigated directionality bias as the orientation between control and translocated groups, homing tendency as the correlation between movements after translocation and translocation distance, and homing accuracy as the variation in distance between final and initial capture points. Our results provide clear evidence that translocation changes the movement behavior of these toads and that they possess homing tendencies outside of their breeding season. Toads had a strong directional bias to move in the opposite direction to the one in which they were artificially displaced, in contrast with the control group, which showed no directional bias among 61 recorded 24-h movements. This tendency for amphibians to home after artificial displacement might be a significant confounding factor in any procedure involving their relocation.
{"title":"Artificial Displacement Alters Movement Behavior of a Terrestrial Amphibian","authors":"Nathalie Jreidini, D. Green","doi":"10.1655/Herpetologica-D-21-00031","DOIUrl":"https://doi.org/10.1655/Herpetologica-D-21-00031","url":null,"abstract":"Abstract: Homing abilities have been widely documented in amphibians, but it remains unclear whether individuals have homing tendencies in the absence of motivational cues related to breeding and site fidelity. We tested whether artificial displacement would affect the movement behavior of a nonphilopatric terrestrial amphibian, the Fowler's Toad (Anaxyrus fowleri), within its home range and after its breeding season had ended. We translocated 65 male and female Fowler's Toads from their initial points of capture a total of 104 times over one of three different distances (100 m, 250 m, and 500 m) and compared these toads' subsequent 24-h movements with those of a control group of 43 untranslocated toads. To shield the translocated toads from auditory, visual, and olfactory cues en route, we translocated them in opaque enclosed boxes and performed the experiment in the uniformly unobstructed landscape of the Lake Erie shoreline of Long Point, ON, Canada. We mainly investigated directionality bias as the orientation between control and translocated groups, homing tendency as the correlation between movements after translocation and translocation distance, and homing accuracy as the variation in distance between final and initial capture points. Our results provide clear evidence that translocation changes the movement behavior of these toads and that they possess homing tendencies outside of their breeding season. Toads had a strong directional bias to move in the opposite direction to the one in which they were artificially displaced, in contrast with the control group, which showed no directional bias among 61 recorded 24-h movements. This tendency for amphibians to home after artificial displacement might be a significant confounding factor in any procedure involving their relocation.","PeriodicalId":56312,"journal":{"name":"Herpetologica","volume":"78 1","pages":"154 - 160"},"PeriodicalIF":2.4,"publicationDate":"2022-09-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49336945","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-09-06DOI: 10.1655/HERPETOLOGICA-D-22-00001
Eric T. Hileman, R. Powell, M. Gifford
Abstract: Invasive species are a major threat and primary driver of vertebrate extinctions on islands, including native and endemic lizards such as West Indian Groundlizards (Genus Pholidoscelis). The genus comprises 19 extant species that range collectively from the Bahamas through the Greater Antilles south to Dominica in the Lesser Antilles. Few studies have addressed aspects of Groundlizard population ecology despite invasive mammals being implicated in Groundlizard declines and three extinctions. From 2007 to 2011, we conducted a capture–recapture study of Puerto Rican Giant Groundlizards (Pholidoscelis exsul) on Guana Island. Guana Island is privately owned and hosts a small number of feral cats, but is mongoose-free and has otherwise experienced only minor human modification since the mid-18th Century. Thus, the island provides a unique opportunity to study lizard demography under conditions minimally impacted by human activities. Our objective was to establish benchmark demographic parameter estimates of P. exsul that may be used in future studies to detect ecological changes. We hypothesized that lizards would be encountered more frequently in disturbed habitat than in less-disturbed habitat because of available anthropogenic food subsidies. We also predicted that large lizards would have higher annual survival rates than would small lizards, and lizards with higher indices of body condition would have correspondingly higher annual survival rates than lizards of the same size class with lower indices of body condition. Our results showed that male growth rates were comparable to similar studies, and individuals reached the presumed size of sexual maturity within 1 yr, with growth rates declining thereafter. Annual survival increased with size class (small = 0.155, 95% confidence interval [CI] = 0.069–0.312; large = 0.518, 95% CI = 0.374–0.660), but we found no evidence of a body condition effect on annual survival. The probability of mortality increased to 99.4% by age 6, but evidence of senescence via declining body condition was apparent sooner. Daily capture probabilities were higher in heavily modified habitat (0.081, 95% CI = 0.049–0.132) than in relatively natural habitat (0.025, 95% CI = 0.012–0.054). Mean maximum distance moved between recaptures was 24.4 m (2–350 m). Estimates of annual abundance ranged from 139 to 250 individuals. Density estimates among years based on the upper confidence limit ranged from 41.9–81.5 individuals/ha within the core sampling area (6.01 ha) and 20.1–39.2 individuals/ha when a 12.5-m buffer strip was incorporated into the effective sampling area.
{"title":"Senescence and Differential Size-Based Survival in Puerto Rican Giant Groundlizards, Pholidoscelis exsul (Squamata: Teiidae), on Guana Island, British Virgin Islands","authors":"Eric T. Hileman, R. Powell, M. Gifford","doi":"10.1655/HERPETOLOGICA-D-22-00001","DOIUrl":"https://doi.org/10.1655/HERPETOLOGICA-D-22-00001","url":null,"abstract":"Abstract: Invasive species are a major threat and primary driver of vertebrate extinctions on islands, including native and endemic lizards such as West Indian Groundlizards (Genus Pholidoscelis). The genus comprises 19 extant species that range collectively from the Bahamas through the Greater Antilles south to Dominica in the Lesser Antilles. Few studies have addressed aspects of Groundlizard population ecology despite invasive mammals being implicated in Groundlizard declines and three extinctions. From 2007 to 2011, we conducted a capture–recapture study of Puerto Rican Giant Groundlizards (Pholidoscelis exsul) on Guana Island. Guana Island is privately owned and hosts a small number of feral cats, but is mongoose-free and has otherwise experienced only minor human modification since the mid-18th Century. Thus, the island provides a unique opportunity to study lizard demography under conditions minimally impacted by human activities. Our objective was to establish benchmark demographic parameter estimates of P. exsul that may be used in future studies to detect ecological changes. We hypothesized that lizards would be encountered more frequently in disturbed habitat than in less-disturbed habitat because of available anthropogenic food subsidies. We also predicted that large lizards would have higher annual survival rates than would small lizards, and lizards with higher indices of body condition would have correspondingly higher annual survival rates than lizards of the same size class with lower indices of body condition. Our results showed that male growth rates were comparable to similar studies, and individuals reached the presumed size of sexual maturity within 1 yr, with growth rates declining thereafter. Annual survival increased with size class (small = 0.155, 95% confidence interval [CI] = 0.069–0.312; large = 0.518, 95% CI = 0.374–0.660), but we found no evidence of a body condition effect on annual survival. The probability of mortality increased to 99.4% by age 6, but evidence of senescence via declining body condition was apparent sooner. Daily capture probabilities were higher in heavily modified habitat (0.081, 95% CI = 0.049–0.132) than in relatively natural habitat (0.025, 95% CI = 0.012–0.054). Mean maximum distance moved between recaptures was 24.4 m (2–350 m). Estimates of annual abundance ranged from 139 to 250 individuals. Density estimates among years based on the upper confidence limit ranged from 41.9–81.5 individuals/ha within the core sampling area (6.01 ha) and 20.1–39.2 individuals/ha when a 12.5-m buffer strip was incorporated into the effective sampling area.","PeriodicalId":56312,"journal":{"name":"Herpetologica","volume":"78 1","pages":"184 - 191"},"PeriodicalIF":2.4,"publicationDate":"2022-09-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42490504","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-09-06DOI: 10.1655/Herpetologica-D-20-00061
Traci D. Castellón, Anna C. Deyle, Anna L. Farmer, J. Bauder, E. A. Roznik, Steve A. Johnson
Abstract: Translocation is increasingly used to move animals of conservation concern away from sites where habitat will be destroyed (mitigation translocation), but outcomes have rarely been adequately monitored, particularly for amphibians. We used radiotelemetry monitoring to assess survival and movement of 23 experimentally translocated, adult Gopher Frogs (Lithobates capito) at a recipient site in north-central Florida, USA. Although posttranslocation monitoring was our primary goal, we also compared our results with those of 24 nontranslocated frogs that were monitored in three previous efforts, conducted at different locations and times. For both translocated and nontranslocated frogs, movement was the most important predictor of mortality, with translocated frogs having a significantly higher probability of movement and higher mortality during the first month following release. However, there was no effect of translocation on survival after controlling for probability of movement because movement was dangerous for both translocated and nontranslocated frogs. Movement by translocated frogs was likely a behavioral response to the translocation experience, whereas movement by nontranslocated frogs was associated with breeding pond visitation, which was not observed within the translocated group. Survival was high for both groups once they settled into underground refugia and movement declined. Despite the comparatively high mortality of translocated frogs immediately following release, more than half survived to the end of monitoring and remained in the vicinity of the release site, meeting an early benchmark of translocation success.
{"title":"Effects of Translocation on Gopher Frog Survival and Movement","authors":"Traci D. Castellón, Anna C. Deyle, Anna L. Farmer, J. Bauder, E. A. Roznik, Steve A. Johnson","doi":"10.1655/Herpetologica-D-20-00061","DOIUrl":"https://doi.org/10.1655/Herpetologica-D-20-00061","url":null,"abstract":"Abstract: Translocation is increasingly used to move animals of conservation concern away from sites where habitat will be destroyed (mitigation translocation), but outcomes have rarely been adequately monitored, particularly for amphibians. We used radiotelemetry monitoring to assess survival and movement of 23 experimentally translocated, adult Gopher Frogs (Lithobates capito) at a recipient site in north-central Florida, USA. Although posttranslocation monitoring was our primary goal, we also compared our results with those of 24 nontranslocated frogs that were monitored in three previous efforts, conducted at different locations and times. For both translocated and nontranslocated frogs, movement was the most important predictor of mortality, with translocated frogs having a significantly higher probability of movement and higher mortality during the first month following release. However, there was no effect of translocation on survival after controlling for probability of movement because movement was dangerous for both translocated and nontranslocated frogs. Movement by translocated frogs was likely a behavioral response to the translocation experience, whereas movement by nontranslocated frogs was associated with breeding pond visitation, which was not observed within the translocated group. Survival was high for both groups once they settled into underground refugia and movement declined. Despite the comparatively high mortality of translocated frogs immediately following release, more than half survived to the end of monitoring and remained in the vicinity of the release site, meeting an early benchmark of translocation success.","PeriodicalId":56312,"journal":{"name":"Herpetologica","volume":"78 1","pages":"161 - 168"},"PeriodicalIF":2.4,"publicationDate":"2022-09-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46775288","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-09-06DOI: 10.1655/Herpetologica-D-22-00005
R. Andrews, A. Rand
Abstract: I present the results of 50 yr (1971–2020) of annual censuses of Anolis apletophallus on Barro Colorado Island, Panama. The main objectives were to assess why abundance in end-of-the-year censuses varied substantially from year to year and why it declined over time. Abundance was negatively correlated with annual rainfall, 90% of which occurs in the wet season when eggs are laid. Lizard abundance is indirectly linked to rainfall through the interaction between Anolis eggs and their major predator, Solenopsis ants. More eggs are killed by ants when rainfall is relatively high because ants are more active and encounter more eggs than when rainfall is relatively low. While rainfall accounts for variability in abundance, it has not changed over time and thus may not account for the overall decline in abundance. Model selection of AICc analyses identified two other factors correlated with abundance. Abundance was positively correlated with the Southern Oscillation Index (SOI) lagged by 1 yr. High SOI (and high abundance) is associated with cool and wet La Niña conditions and low values with dry and warm El Niño conditions. The prediction that low abundance is associated with dry and warm El Niño conditions (low SOI) conflicts with the negative correlation between abundance and rainfall where low abundance is associated with high rainfall. Moreover, abundance was negatively correlated with Tmin (minimum annual temperature). The mechanism by which increasing Tmin during the census period is linked to declining abundance is unknown. Three climatic factors are correlated with lizard abundance, but none of them explain why abundance has declined. A third objective was to examine the relationship between species richness and species dominance of Anolis communities with respect to rainfall patterns. Tropical forests typically have a maximal richness of 7–8 species. Our study sites in Panama have high species richness, but Anolis apletophallus individuals made up ≥96% of all records, an unexpected level of species dominance. Comparisons among sites suggest that the number of Anolis species in a community is related to annual rainfall, and dominance is related to seasonality of rainfall. Dry forests have few Anolis species and wet forests have as many as 7–8 species. Forests with short wet seasons (months with >100 mm rainfall) have a high likelihood that individuals of one species will dominate the community.
{"title":"Fifty Years of Observations on Anolis Lizards at Barro Colorado Island, Panama","authors":"R. Andrews, A. Rand","doi":"10.1655/Herpetologica-D-22-00005","DOIUrl":"https://doi.org/10.1655/Herpetologica-D-22-00005","url":null,"abstract":"Abstract: I present the results of 50 yr (1971–2020) of annual censuses of Anolis apletophallus on Barro Colorado Island, Panama. The main objectives were to assess why abundance in end-of-the-year censuses varied substantially from year to year and why it declined over time. Abundance was negatively correlated with annual rainfall, 90% of which occurs in the wet season when eggs are laid. Lizard abundance is indirectly linked to rainfall through the interaction between Anolis eggs and their major predator, Solenopsis ants. More eggs are killed by ants when rainfall is relatively high because ants are more active and encounter more eggs than when rainfall is relatively low. While rainfall accounts for variability in abundance, it has not changed over time and thus may not account for the overall decline in abundance. Model selection of AICc analyses identified two other factors correlated with abundance. Abundance was positively correlated with the Southern Oscillation Index (SOI) lagged by 1 yr. High SOI (and high abundance) is associated with cool and wet La Niña conditions and low values with dry and warm El Niño conditions. The prediction that low abundance is associated with dry and warm El Niño conditions (low SOI) conflicts with the negative correlation between abundance and rainfall where low abundance is associated with high rainfall. Moreover, abundance was negatively correlated with Tmin (minimum annual temperature). The mechanism by which increasing Tmin during the census period is linked to declining abundance is unknown. Three climatic factors are correlated with lizard abundance, but none of them explain why abundance has declined. A third objective was to examine the relationship between species richness and species dominance of Anolis communities with respect to rainfall patterns. Tropical forests typically have a maximal richness of 7–8 species. Our study sites in Panama have high species richness, but Anolis apletophallus individuals made up ≥96% of all records, an unexpected level of species dominance. Comparisons among sites suggest that the number of Anolis species in a community is related to annual rainfall, and dominance is related to seasonality of rainfall. Dry forests have few Anolis species and wet forests have as many as 7–8 species. Forests with short wet seasons (months with >100 mm rainfall) have a high likelihood that individuals of one species will dominate the community.","PeriodicalId":56312,"journal":{"name":"Herpetologica","volume":"78 1","pages":"145 - 153"},"PeriodicalIF":2.4,"publicationDate":"2022-09-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48891974","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-09-06DOI: 10.1655/Herpetologica-D-20-00042
J. Brooks, John Rohrer, Daniel D. Beck
Abstract: Northern Pacific Rattlesnakes (Crotalus oreganus) are ambush-hunting predators that rely on crypsis to forage and to avoid encounters with predators, yet little is known about color variation in this ubiquitous rattlesnake species. This study addressed how coloration and contrast in tail banding in C. oreganus vary among habitat types in Washington State. We also explored whether C. oreganus exhibit sexual dimorphism in coloration or tail band contrast (sexual dichromatism). We sampled 127 rattlesnakes from seven different populations across northern and central Washington state during spring emergence from overwintering hibernacula in 2017 and 2018. We characterized snake coloration as red/blue color ratios from standardized photographs, and used GIS supervised classification schemes of satellite imagery to characterize habitat. We used generalized linear models to assess relationships among snake color and tail bands, habitat, and sex. We found that coloration (red/blue color ratios) in C. oreganus varied greatly across the landscape, both within and among populations, likely a reflection of their variable and heterogenous shrub-steppe and forest ecotone habitats. In 20% of 21 pairwise comparisons, populations differed in body color. Rattlesnake coloration was not associated with habitat (amount of forested land within 0.5 km of the snake den), but male and female rattlesnakes showed different associations between color and percent forested habitat. Male rattlesnakes did not differ in body coloration from females, but males showed greater contrast than females in the black and white banding present on the tail. We discuss several, nonmutually exclusive, hypotheses for sexual dichromatism in tail band contrast, including the possibility that tail banding constitutes warning coloration in rattlesnakes. Our results suggest that sexual dichromatism, and the role of tail banding in rattlesnake ecology, are topics worthy of further investigation.
{"title":"Color Variation, Tail Banding, and Sexual Dichromatism in Washington Populations of Northern Pacific Rattlesnakes, Crotalus oreganus","authors":"J. Brooks, John Rohrer, Daniel D. Beck","doi":"10.1655/Herpetologica-D-20-00042","DOIUrl":"https://doi.org/10.1655/Herpetologica-D-20-00042","url":null,"abstract":"Abstract: Northern Pacific Rattlesnakes (Crotalus oreganus) are ambush-hunting predators that rely on crypsis to forage and to avoid encounters with predators, yet little is known about color variation in this ubiquitous rattlesnake species. This study addressed how coloration and contrast in tail banding in C. oreganus vary among habitat types in Washington State. We also explored whether C. oreganus exhibit sexual dimorphism in coloration or tail band contrast (sexual dichromatism). We sampled 127 rattlesnakes from seven different populations across northern and central Washington state during spring emergence from overwintering hibernacula in 2017 and 2018. We characterized snake coloration as red/blue color ratios from standardized photographs, and used GIS supervised classification schemes of satellite imagery to characterize habitat. We used generalized linear models to assess relationships among snake color and tail bands, habitat, and sex. We found that coloration (red/blue color ratios) in C. oreganus varied greatly across the landscape, both within and among populations, likely a reflection of their variable and heterogenous shrub-steppe and forest ecotone habitats. In 20% of 21 pairwise comparisons, populations differed in body color. Rattlesnake coloration was not associated with habitat (amount of forested land within 0.5 km of the snake den), but male and female rattlesnakes showed different associations between color and percent forested habitat. Male rattlesnakes did not differ in body coloration from females, but males showed greater contrast than females in the black and white banding present on the tail. We discuss several, nonmutually exclusive, hypotheses for sexual dichromatism in tail band contrast, including the possibility that tail banding constitutes warning coloration in rattlesnakes. Our results suggest that sexual dichromatism, and the role of tail banding in rattlesnake ecology, are topics worthy of further investigation.","PeriodicalId":56312,"journal":{"name":"Herpetologica","volume":"78 1","pages":"192 - 200"},"PeriodicalIF":2.4,"publicationDate":"2022-09-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48090630","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-09-06DOI: 10.1655/Herpetologica-D-22-00004
A.A. Thasun Amarasinghe, Sanjaya K. Bandara, Sanjaya Weerakkody, Patrick D. Campbell, D. Marques, A. D. Danushka, A. de Silva, G. Vogel
Abstract: Based on phylogenetic and morphological characters, we revise the systematics of the natricid genus Fowlea in Sri Lanka, comprising two morphospecies. The taxonomy of the Sri Lankan populations has long been controversial, and one of the species has, for more than a decade, been listed as Xenochrophis cf. piscator. Although the Sri Lankan populations are morphologically allied to Fowlea piscator in India, they are genetically highly divergent from the eastern Indian F. piscator sensu lato with a p-distance of 9.9–12.3%, and from southwestern Indian Fowlea species with a p-distance of 4.9–11.1% in the mitochondrial cytochrome b gene. Here, we resurrect Müller's (1887) variety, Tropidonotus quincunciatus var. unicolor, as a distinct taxon, elevate it to the species level, and assign it to the genus Fowlea. Therefore, the population so far recognized as X. cf. piscator will be treated hereafter as F. unicolor and we redescribe it and its holotype (by monotypy). We tentatively restrict this species to Sri Lanka and state the possibility of a population in southern India too. The second distinct species, Fowlea asperrima, which is endemic to Sri Lanka, has long been confused with its sympatric congener, F. unicolor comb. nov., and we designate a lectotype and redescribe it herein. Currently, nine species of the genus Fowlea are now recognized, but it is likely that further species (including those regarded as subjective synonyms) remain unrecognized.
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