Bufo Americanus Research Articles

Morphology and vocalization comparison of the Houston Toad and the Dwarf American Toad: implications for their historic range.

Documenting changes in the distribution and abundance of a given taxon requires historical data. In the absence of long-term monitoring data collected throughout the range of a taxon, conservation biologists often rely on preserved museum specimens to determine the past or present, putative geographic distribution. Distributional data for the Houston Toad (Anaxyrus houstonensis) has consistently been confounded by similarities with a sympatric congener, the Dwarf American Toad (A. americanus charlesmithi), both in monitoring data derived from chorusing surveys, and in historical data via museum specimens. In this case, misidentification can have unintended impacts on conservation efforts, where the Houston Toad is federally endangered, and the Dwarf American Toad is of least concern. Previously published reports have compared these two taxon on the basis of their male advertisement call and morphological appearance, often with the goal of using these characters to substantiate their taxonomic status prior to the advent of DNA sequencing technology. However, numerous studies report findings that contradict one another, and no consensus on the true differences or similarities can be drawn. Here, we use contemporary recordings of wild populations of each taxon to test for quantifiable differences in male advertisement call. Additionally, we quantitatively examine a subset of vouchered museum specimens representing each taxon to test previously reported differentiating morphometric characters used to distinguish among other Bufonids of East-Central Texas, USA. Finally, we assemble and qualitatively evaluate a database of photographs representing catalogued museum vouchers for each taxon to determine if their previously documented historic ranges may be larger than are currently accepted. Our findings reveal quantifiable differences between two allopatric congeners with respect to their male advertisement call, whereas we found similarities among their detailed morphology. Additionally, we report on the existence of additional, historically overlooked, museum records for the Houston Toad in the context of its putative historic range, and discuss errors associated with the curation of these specimens whose identity and nomenclature have not been consistent through time. These results bookend decades of disagreement regarding the morphology, voice, and historic distribution of these taxa, and alert practitioners of conservation efforts for the Houston Toad to previously unreported locations of occurrence.

Ecotoxicological Characterization of Lithium as a "Timebomb" in Aquatic Systems: Tadpoles of the South American Toad Rhinella arenarum (Hensel, 1867) as Model Organisms.

The aim of this study was to evaluate the acute lethality and chronic sublethal effects of lithium (Li) on Rhinella arenarum tadpoles as model organisms. First a 96 h toxicity assay was performed by exposing tadpoles to Li concentrations from 44.08 to 412.5 mg L-1 to estimate the mortality, and lethal and sublethal effects. Another bioassay was carried out by exposing tadpoles to two environmentally relevant Li concentrations (2.5 and 20 mg L-1) for one and two weeks. The sublethal effects of Li on tadpoles were evaluated by analyzing biochemical, genotoxic, and physiological biomarkers. The mortality in Li-exposed tadpoles increased over time. The median lethal concentration (LC50) ranged from 319.52 (281.21-363.05) mg L-1 at 48 h to 66.92 (52.76-84.89) mg L-1 at 96 h. Exposure to Li at 2.5 and 20 mg L-1 induced alterations in enzymes related to detoxification, antioxidant, and hepatic mechanisms, endocrine disruption of thyroid hormones, genotoxicity, and effects on the physiology of the heart and gastrointestinal systems. Tadpoles exposed to the highest concentration in the chronic bioassay (20 mg L-1 Li), which is the concentration commonly recorded in Li mining sites, showed significant mortality after one week of exposure. These results warn about the high ecotoxicological risk of Li as a contaminant of emerging concern for amphibians.

Toxicity assessment of a tebuconazole-based fungicide on the embryo-larval development of the common south American toad Rhinella arenarum.

Agrochemicals cause diverse effects on aquatic communities, and amphibian species are particularly threatened due the high susceptibility to contamination. Present study evaluates the toxicity of a widely used fungicide tebuconazole (Trigal®) by the assessment of mortality and developmental alterations at acute, subchronic, and chronic exposure during the embryo-larval development of the South American toad Rhinella arenarum. Also, the sensitivity of the different embryonic stages was evaluated with 24-h pulse exposure treatments. The results demonstrated that larvae were more sensitive than embryos at acute exposure (LC50-24 and 96 h = 74.62, 31.92 mg/L and 24.27, 16.81 mg/L for embryos and larvae, respectively). Nevertheless, embryos toxicity increased significantly achieving a sensitivity very similar to larvae at chronic exposure (LC50-168 and 504 h = 13.31, 4.35 mg/L and 14.47, 6.83 mg/L for embryos and larvae, respectively). Embryos exhibited several sublethal effects from 5 mg/L at 96 h onwards, such as delayed development, reduce body size, edemas, tail/axial flexures, weakness, and absence of movements. The teratogenic index at 96 h was 10.13, indicating the severe teratogenic potential of the fungicide. 24-h pulse exposure treatments showed an increased sensitivity in intermediate stages as S.11, S.18, S20, and S.23 (NOEC-96 h = 100, 200, 75, and 20 mg/L, respectively), while stage S.25 was the most sensitive to the fungicide (NOEC-96 h = 5 mg/L). About metamorphic process, tebuconazole caused an acceleration of metamorphosis at the lowest concentration (0.001 mg/L), but also an increase in mortality and in addition, significant differences in the weight in all treatments. The results obtained throughout this work indicate that tebuconazole cause several adverse effects in Rhinella arenarum embryo-larval development.

Cytotoxicity of the field lampricide 3-trifluoromethyl-4-nitrophenol (TFM) in tadpole cell lines from North American frogs.

The common field lampricide, 3-trifluoromethyl-4-nitrophenol (TFM), is used to treat streams and creeks infested with highly invasive and destructive sea lamprey (Petromyzon marinus) in the tributaries of the Great Lakes. Unfortunately, amphibian deaths have been reported following stream treatments with TFM. Larval amphibians (tadpoles) are more susceptible to TFM toxicity than adult amphibians. The aim of this study was to test the toxicity of TFM in eight new tadpole cell lines from the green frog (Lithobates clamitans), wood frog (Lithobates sylvaticus), and American toad (Anaxyrus americanus). A cell viability bioassay using two fluorescent dyes, Alamar Blue and CFDA-AM, was performed following 24-h and 72-h exposures to a range of TFM concentrations. In general, TFM exposure reduced Alamar Blue fluorescence more rapidly than CFDA-AM fluorescence in tadpole cells, suggesting that Alamar Blue is perhaps a better diagnostic indicator of cell health for acute TFM cytotoxicity. At present, the in vivo 96-h LC50s of TFM are only available for L. clamitans and they correlated well with the in vitro EC50 values for the green frog tadpole cell lines in this study. The eight tadpole cell lines with different relative sensitivities to TFM cytotoxicity could prove to be useful tools in assessing next-generation lampricides in high-throughput bioassays to ensure safety in frogs before their sea lamprey-targeted application in the field.

Combining two user-friendly machine learning tools increases species detection from acoustic recordings

Passive acoustic monitoring usually generates large datasets that require machine learning algorithms to scan sound files, although the complexity of developing machine learning algorithms can be a barrier. We assessed the ability and speed of two user-friendly machine learning tools, Kaleidoscope Pro and BirdNET, for detecting the American toad ( Anaxyrus americanus (Holbrook, 1836)) in sound recordings. We developed a two-step approach, combining both tools to maximize species detection while minimizing the time needed for output verification. When considered separately, Kaleidoscope Pro successfully detected the American toad in 85.9% of recordings in the validation dataset, while BirdNET detected the species in 58.4% of recordings. Combining the two tools in the two-step approach increased the detection rate to 93.3%. We applied the two-step approach to a large acoustic dataset ( n = 6194 recordings). We started by scanning the dataset using Kaleidoscope Pro (species detected in 417 recordings), then we used BirdNET on the remaining recordings without confirmed presence. The two-step approach reduced the scanning time, the time needed for output verification, and added 37 additional species detections in 45 min. Our findings highlight that combining machine learning tools can improve species detectability while minimizing time and effort.

Conservation genomics of an endangered montane amphibian reveals low population structure, low genomic diversity and selection pressure from disease.

Wildlife diseases are a major global threat to biodiversity. Boreal toads (Anaxyrus [Bufo] boreas) are a state-endangered species in the southern Rocky Mountains of Colorado and New Mexico, and a species of concern in Wyoming, largely due to lethal skin infections caused by the amphibian chytrid fungus Batrachochytrium dendrobatidis (Bd). We performed conservation and landscape genomic analyses using single nucleotide polymorphisms from double-digest, restriction site-associated DNA sequencing in combination with the development of the first boreal toad (and first North American toad) reference genome to investigate population structure, genomic diversity, landscape connectivity and adaptive divergence. Genomic diversity (π = 0.00034-0.00040) and effective population sizes (Ne = 8.9-38.4) were low, likely due to post-Pleistocene founder effects and Bd-related population crashes over the last three decades. Population structure was also low, likely due to formerly high connectivity among a higher density of geographically proximate populations. Boreal toad gene flow was facilitated by low precipitation, cold minimum temperatures, less tree canopy, low heat load and less urbanization. We found >8X more putatively adaptive loci related to Bd intensity than to all other environmental factors combined, and evidence for genes under selection related to immune response, heart development and regulation and skin function. These data suggest boreal toads in habitats with Bd have experienced stronger selection pressure from disease than from other, broad-scale environmental variations. These findings can be used by managers to conserve and recover the species through actions including reintroduction and supplementation of populations that have declined due to Bd.

Comparative efficacy of eDNA and conventional methods for monitoring wetland anuran communities

Documenting biodiversity, species occurrence, and species status require reliable monitoring techniques, but the complex life history and cryptic behavior of many anurans create challenges for conventional monitoring approaches. Environmental DNA (eDNA) surveys are a promising alternative (or complement) to conventional anuran monitoring, but their relative success has not been fully tested. We assessed the comparative efficacy of targeted eDNA detection via quantitative PCR (qPCR) and three conventional amphibian survey methods (visual encounter, breeding call, and larval dipnet surveys) for detecting nine anuran species in natural wetlands in southern Ontario, Canada. Our analyses revealed that all assessment methods yielded imperfect detection, with visual encounter and eDNA surveys detecting the greatest species richness and eDNA surveys requiring the fewest sampling events. Amphibian community composition results differed among survey methods and sampling events, and detection efficacy was markedly variable, with some species requiring two to three methods to maximize detection success. Notably, two relatively terrestrial species (Anaxyrus americanusandHyla versicolor) had relatively low and seasonally variable eDNA detection rates, suggesting that species-specific ecology likely affects eDNA presence or detection. These findings suggest that optimized monitoring for complex anuran communities may require application of multiple monitoring methods, which may need to be tailored to individual target species or communities.

Inter‐annual variation in amphibian larval interspecies interactions

AbstractThe outcomes of species interactions can vary by life stage, year, and surrounding environmental conditions. Amphibian species are expected to compete most strongly during their tadpole stage when they exist in the highest densities. Changes in arrival timing, surrounding aquatic communities, and yearly conditions could all affect the outcome of larval competition. In Long Point, Ontario, the Fowler's toad (Anaxyrus fowleri) is at the northern edge of its range and overlaps with the more common American toad (Anaxyrus americanus). Both species breed in ponds that encounter high inter‐annual variation. To determine whether these species compete strongly, and if this effect was replicated across multiple years, we raised both species as tadpoles together and, apart, in mesocosms in 2018 and 2021. We measured survivorship to, weight at, and time to metamorphosis for both species in both years. We determined that the presence of American toad tadpoles consistently had a detrimental effect on Fowler's toad tadpoles, even though this effect presented itself differently across years. Our study suggests that competitive exclusion by American toads could be occurring at the edge of the Fowler's toad's range. This study further demonstrates the importance of studying communities across multiple years to understand the full scope of species interactions.

Evaluating the interactive effects of artificial light at night and background color on tadpole crypsis, background adaptation efficacy, and growth

Artificial light at night (ALAN) is a global pollutant of rising concern. While alterations to natural day-night cycles caused by ALAN can affect a variety of traits, the broader fitness and ecological implications of these ALAN-induced shifts remain unclear. This study evaluated the interactive effects of ALAN and background color on traits that have important implications for predator-prey interactions and fitness: crypsis, background adaptation efficacy, and growth. Using three amphibian species as our models, we discovered that: (1) Exposure to ALAN reduced the ability for some species to match their backgrounds (background adaptation efficacy), (2) Crypsis and background adaptation efficacy were enhanced when tadpoles were exposed to dark backgrounds only, emphasizing the importance of environmental context when evaluating the effects of ALAN, (3) ALAN and background color have a combined effect on a common metric of fitness (growth), and (4) Effects of ALAN were not generalizable across amphibian species, supporting calls for more studies that utilize a diversity of species. Notably, to our knowledge, we found the first evidence that ALAN can diminish background adaptation efficacy in an amphibian species (American toad tadpoles). Collectively, our study joins others in highlighting the complex effects of ALAN on wildlife and underscores the challenges of generalizing ALAN's effect across species, emphasizing the need for a greater diversity of species and approaches used in ALAN research.

Gonadal morphogenesis in the South American toad Rhinella Arenarum (Anura, Bufonidae) unveils an extremely delayed rate of sex differentiation.

Among anurans, Bufonids are recognized for their retarded sex differentiation. However, few studies have addressed gonadal morphogenesis in this family. Here, we analyzed the early gonadogenesis in laboratory-reared Rhinella arenarum. Few germ cells were identified in the genital ridge at Gosner stage 26. At metamorphosis, somatic cells and germ cells were observed in the outer region of the undifferentiated gonad, whereas the central region was occupied by stromal tissue. A cortico-medullary organization was first recognized on Day 7 postmetamorphosis. The cortex was composed of germ cells and encompassing epithelial cells, whereas the medulla contained cells presumptively derived from the coelomic epithelium. Medullary somatic cells formed metameric knots along the length of the undifferentiated gonad. Consequently, a series of 12-14 gonomeres became recognizable externally. The first sign of ovarian differentiation was observed on Day 15 postmetamorphosis, when a cavity was formed within each gonomere. In contrast, testes were recognized by a uniform distribution of germ cells and intermingled somatic cells, as the division into cortex and medulla was lost. By Day 50 postmetamorphosis, the gonadal metameric organization was still apparent both in the ovaries and testes. Follicles containing diplotene oocytes were observed within the ovary. In the testis, an incipient lobular architecture was recognized without initiation of meiosis within the seminiferous cords. These observations reveal an extremely delayed gonadal development in R. arenarum, not reported previously for other anuran species. In addition, the late differentiation of the gonads contrasted with the early appearance of follicles in the Bidder's organ. Lastly, we observed that delayed metamorphs exhibited an undifferentiated gonad, demonstrating that gonadogenesis in this species is more dependent on somatic development than on age.

Effects of Herbicides and the Chytrid Fungus Batrachochytrium dendrobatidis on the growth, development and survival of Larval American Toads (Anaxyrus americanus)

Pesticides and pathogens adversely affect amphibian health, but their interactive effects are not well known. We assessed independent and combined effects of two agricultural herbicides and the fungal pathogen Batrachochytrium dendrobatidis (Bd) on the growth, development and survival of larval American toads (Anaxyrus americanus). Wild-caught tadpoles were exposed to four concentrations of atrazine (0.18, 1.8, 18.0, 180 μg/L) or glyphosate (7, 70, 700, 7000 µg a.e./L), respectively contained in Aatrex® Liquid 480 (Syngenta) or Vision® Silviculture Herbicide (Monsanto) for 14 days, followed by two doses of Bd. At day 14, atrazine had not affected survival, but it non-monotonically affected growth. Exposure to the highest concentration of glyphosate caused 100% mortality within 4 days, while lower doses had an increasing monotonic effect on growth. At day 65, tadpole survival was unaffected by atrazine and the lower doses of glyphosate. Neither herbicide demonstrated an interaction effect with Bd on survival, but exposure to Bd increased survival among both herbicide-exposed and herbicide-control tadpoles. At day 60, tadpoles exposed to the highest concentration of atrazine remained smaller than controls, indicating longer-term effects of atrazine on growth, but effects of glyphosate on growth disappeared. Growth was unaffected by any herbicide-fungal interaction but was positively affected by exposure to Bd following exposure to atrazine. Atrazine exhibited a slowing and non-monotonic effect on Gosner developmental stage, while exposure to Bd tended to speed up development and act antagonistically toward the observed effect of atrazine. Overall, atrazine, glyphosate and Bd all showed a potential to modulate larval toad growth and development.

Evaluating fence-end treatments for migratory amphibians

Migratory amphibians require movements to complete their biphasic life cycle, often across altered landscapes fragmented by roadways, which can have severe consequences on their populations. To manage this threat, transportation agencies have begun to implement exclusion fencing to separate natural areas from the roadway to prevent wildlife-vehicle collisions. Although fences are an effective conservation tool, the tendency of animals to access the road by circumventing the fence ends, known as the fence-end effect, threatens to jeopardize management efforts to reduce road associated mortality. One strategy to lessen the impacts of the fence-end effect is to construct fence-end treatments to block amphibian movement and guide the animals to safe crossing locations. By using experimental fence arenas, we examined how nine amphibian species responded to two alternative fence-end structures: horizontal v-shape and perpendicular fence-end treatments. Using a generalized linear model framework, we found both fence-end treatments to be an effective strategy to reduce the impacts of the fence-end effect, with our predictor variable, fence-end treatment, explaining most of the variation in amphibian response. Structure effectiveness also started to improve by 20% with each 7°C increase in temperature, however, this was not significant. Despite these promising findings, we also found for each additional 312 s an amphibians spent attempting to navigate around the experimental fence resulted in a 25% decline in structure effectiveness, suggesting longer fences are not an adequate protection measure to combat the fence-end effect for amphibians. In addition, Anaxyrus americanus was not found to differ in their response, performing equally well to both experimental fence-end treatments. In contrast, Rana spp., Pseudacris crucifer, and Notopthalmus viridescens showed a greater response to the horizontal v-shape fence-end treatment compared to the perpendicular fence-end treatment. Variation in response for Ambystoma spp. could not be detected due to a small sample size; however, no individuals responded positively to the perpendicular fence-end treatment. Guidelines for amphibian fences should continue to incorporate fence-end treatments into the design and implementation to mitigate for the fence-end effect, and preferably angle the fence-ends inward in the horizontal v-shape pattern with the fence ends diagonal to the road for migratory amphibians.

Legacy effects in temporally separated tadpole species are not mediated by invasive Western Mosquitofish (Gambusia affinis).

Temporally separated species are often thought to have limited competition over a shared resource. However, early arriving species may consume a limited resource such that later-arriving species have access to fewer resources and thus experience competitive effects, even if they are temporally separated (i.e., they experience legacy effects from the early species). The presence of a predator might affect potential legacy effects by influencing the behavior or survivorship of the early species. Using a mesocosm experiment, I examined whether the presence of nonnative Western Mosquitofish (Gambusia affinis) mediated legacy effects in the interaction of two temporally separated species of tadpoles, early arriving American Toads (Anaxyrus americanus) and late-arriving Bullfrogs (Rana catesbeiana). Anaxyrus americanus tadpoles reduced R. catesbeiana tadpole growth despite all A. americanus tadpoles metamorphosing 8 days before the introduction of R. catesbeiana tadpoles into the mesocosms (i.e., legacy effects). Gambusia affinis had limited effects on A. americanus (1 day delay in metamorphosis but no effect on survivorship or size at metamorphosis) and positive effects on R. catesbeiana (increased growth). There were no significant interactions between the A. americanus tadpole density and G. affinis treatments. In conclusion, I found evidence of significant legacy effects of A. americanus tadpoles on R. catesbeiana tadpoles, but no evidence that G. affinis mediated the legacy effects.

Exposure to Amphibian Chytrid Fungus Alters Terrestrial Growth and Feeding Rate in Metamorphic Anurans

Population declines and extinctions associated with infectious diseases of wildlife are increasing in both frequency and severity. Response to infectious disease varies among species and individuals, with some appearing asymptomatic and others experiencing rapid mortality. The amphibian chytrid fungus, Batrachochytrium dendrobatidis (Bd), has been associated with widespread population declines and species extinctions, yet in some geographic regions it elicits a range of sublethal responses that may influence population dynamics in ways that are currently not understood. Our central objective was to evaluate growth and feeding behavior of terrestrial juvenile American Toads (Anaxyrus americanus) and Northern Leopard Frogs (Lithobates pipiens) following exposure to Bd. We manipulated foraging effort through the presence or absence of refugia for prey. We found that both amphibian species grew less when exposed to the pathogen, though the mechanisms contributing to this effect appear not to be the same. American Toads ate equal to or more in feeding trials when exposed to Bd than when unexposed, yet those exposed to Bd still experienced growth limitations. Conversely, Northern Leopard Frogs consumed the same quantity of food no matter their exposure status, but refugia presence had an effect on feeding. These results suggest that sublethal effects of disease can have ecologically relevant impacts in amphibians that can result in reduced size, likely because of high metabolic costs of disease response. Size is both a predictor of time to reproduction and fecundity, and reductions in individual growth may have important consequences for populations.

Response of American Toads and Their Invertebrate Prey to Experimentally Elevated Soil pH

Acidification can have broad effects on forest ecosystems, ranging from consequences for individual organisms to alterations in trophic dynamics. While the effects of acidification on certain aspects of forest ecosystems have been well studied, less is known about the influence of soil acidification on the forest floor food web that includes amphibians and invertebrates. We investigated the effects of acidification on the American Toad (Anaxyrus americanus) and its interaction with the forest floor invertebrate community. We evaluated survival, growth, and diet of newly metamorphosed toads placed in terrestrial enclosures in forest plots with either experimentally elevated soil pH or untreated, acidified soils. We also conducted invertebrate pitfall sampling in these two soil pH types to evaluate the trophic interactions between toads and invertebrates. Toad mass after 90 days tended to be larger in plots with elevated soil pH, although survival and diet did not differ between soil pH types. We found no effect of soil pH on invertebrate abundances nor overall invertebrate diversity. We also found no evidence that toads exhibited top-down control of the invertebrate community. Collectively, our results indicate that acidified soils did not affect forest floor trophic dynamics. The presence of temporary enclosures we constructed, however, significantly reduced invertebrate abundances and overall diversity. Thus, the strong effect these structures can have on invertebrate communities should be considered when used in future studies.

Assessing the Impact of Chemical Algae Management Strategies on Anurans and Aquatic Communities.

Pond management with chemical and biological agents that reduce overgrowth of algae is an important means of maintaining water quality in residential ponds, yet the effects on nontarget species are not fully understood. We assessed the impact of Aquashade (a common nontoxic pond dye) and copper sulfate (a toxic algaecide) on American toad (Anaxyrus americanus), northern leopard frog (Lithobates pipiens), and Cope's gray treefrog (Hyla chrysoscelis) metamorphosis in outdoor mesocosm experiments. We also evaluated the relative impact of tadpole grazing versus chemical treatment on phytoplankton and periphyton abundance. We found no significant effects of pond management treatment on anuran metamorphosis, suggesting that addition of Aquashade and copper sulfate at tested concentrations does not significantly impact anurans under these experimental conditions. Interestingly, we found that the presence of tadpoles more strongly reduced algal abundance than Aquashade or copper sulfate by significantly decreasing phytoplankton and periphyton abundance over time. The present study suggests that anuran tadpoles may be effective at maintaining water quality, and that Aquashade and copper sulfate may have minimal effects on amphibian metamorphosis. Environ Toxicol Chem 2023;42:213-224. © 2022 The Authors. Environmental Toxicology and Chemistry published by Wiley Periodicals LLC on behalf of SETAC.

Community Structure of Terrestrial Vertebrates in a Restored Meadow Habitat in Pennsylvania: Assessing the Potential Prey Base for Eastern Massasauga Rattlesnakes

We sampled the vertebrate community of a 20-ha conservation easement in Venango County, PA, from April through August 2021. The restoration and management efforts on this easement were designed to improve the meadow habitat for one of the few remaining populations of Sistrurus catenatus (Eastern Massasauga Rattlesnake) in Pennsylvania, and our sampling efforts were focused on evaluating the potential prey base available to the rattlesnakes at this site. We identified 9 amphibian species, 10 reptile species, and 11 small mammal species. For amphibians, Anaxyrus americanus (American Toad) was the most abundant species, accounting for 32.6% of the total, followed by Notophthalmus viridescens (Red-Spotted Newt) with 30.6% of total abundance. Thamnophis brachystoma (Short-Headed Gartersnake) comprised more than half (53.7%) of all reptiles sampled, followed by Thamnophis sirtalis (Eastern Gartersnake; 22.7%). Peromyscus leucopus (White-Footed Mouse) was the most abundant mammal species, accounting for 37.4% of all mammals surveyed, followed by Microtus pennsylvanicus (Eastern Meadow Vole; 24.8%). Mammals had the greatest species richness (S = 11), while reptiles had the greatest total abundance (TA = 361), and amphibians had the greatest species evenness (E = 0.799). Species accounts for Venango County indicate that we sampled 40.9% (9/22), 37.0% (10/27), and 21.2% (11/52) of the known amphibian, reptilian, and mammalian species, respectively, within this restored meadow habitat. Our results suggest that the restoration efforts on this easement study site have been extremely effective in creating meadow habitat that supports a diversity of prey species for the Eastern Massasauga Rattlesnake.

Non‐native stinging ant interactions with native anurans

AbstractNative predators may ignore or avoid non‐native prey because they do not recognize the novel organisms as food, or the invasive prey may bring antipredatory defences against which the native predators have not co‐evolved a sufficient attack. Non‐native ants successfully invade novel habitats worldwide and, in eastern North America, several invasive ant species bring venomous stings in quantities that far exceed that of native ant species. Ants make up a considerable portion of anuran diets, and we investigated how several native anurans reacted to the invasion of the non‐native European fire ant (Myrmica rubra). Myrmica rubra has a venomous sting, and it occurs in aggressive swarms that can deliver multiple stings. Despite these defences, based on field observations, we expected that leopard frogs (Lithobates pipiens) might consume the abundant ants. We also predicted that habitat niche differences from the moisture‐dependent ants would limit consumption by the more terrestrial American toads (Anaxyrus americanus) and more aquatic green frogs (Lithobates clamitans). Our results suggested that none of the anuran species make use of the M. rubra swarms. The anurans, particularly A. americanus, consumed ample native ants in the field, but not M. rubra ants. In the laboratory, A. americanus ate several M. rubra ants, and L. pipiens a few, but experienced anuran individuals collected from M. rubra‐invaded habitat were less likely to eat the ants in laboratory. Hence, at best, M. rubra invasion appears to supplant rather than supplement anuran food resources.

Gonadal Cycles and Growth to Sexual Maturity of the Eastern American Toad, Anaxyrus americanus americanus (Holbrook, 1836), from Pennsylvania

The Eastern American Toad, Anaxyrus americanus americanus (Holbrook, 1836) is an ubiquitous and geographically wide-ranging subspecies of eastern North America. As such, it also varies geographically in several of its life history traits. A statewide examination of its gonadal cycles and body size-age relationships in Pennsylvania revealed a conformity to contemporary latitudinal patterns associated with these life history traits. Likewise, these very responses to spatial differences in climate, we proffer, predispose the Eastern American Toad to climate-change related shifts in timing of reproduction in Pennsylvania. Such a change, depending upon the reproductive response to climate change by Fowler's Toad, Anaxyrus fowleri (Hinckley, 1882), could result in an increased likelihood of hybridization, a phenomenon with significant evolutionary implications.

A redescription of the poorly known Central American toad Inciliustacanensis (Anura, Bufonidae), with a summary of its biology and conservation status.

Based on examination of most of the existing museum specimens of the rare bufonid frog Inciliustacanensis, we present a redescription and new diagnosis for this species. The species is limited to small region of the Pacific chain of volcanoes in southeastern Chiapas, Mexico, and adjacent areas of Guatemala. The species has not been observed in the wild since 1984 and may have been reduced or eliminated by regional epidemics of chytridiomycosis.