Effects of pathogens on host life-history characteristics can be influenced by changes in the immune system that occur during development as well as by environmental factors that negatively affect immune system function. Amphibians worldwide are experiencing population declines from chytridiomycosis caused by the fungal pathogen Batrachochytrium dendrobatidis. Disease outbreaks can be influenced by timing of exposure to B. dendrobatidis and by abiotic factors, such as pesticides, that could influence susceptibility. To examine the effects of larval pesticide exposure and timing of B. dendrobatidis exposure during development, we exposed Cope’s Gray Treefrogs (Hyla chrysoscelis) to the insecticide malathion throughout larval development and to B. dendrobatidis at 1 or 3 wk posthatching, or after metamorphosis. We reared tadpoles through metamorphosis and then for 28 d in the terrestrial environment to examine treatment effects on larval survival, time to metamorphosis, and mass at metamorphosis, as well as terrestrial survival and growth after metamorphosis. We found that malathion exposure resulted in a decrease in mass at metamorphosis and a decrease in terrestrial growth. Exposure to B. dendrobatidis did not influence larval development, terrestrial growth, or survival, and exposure to malathion appears to not have altered the effects of B. dendrobatidis exposure in a biologically significant way.

In salamanders in the seven families composing the Salamandroidea, sperm storage allows a female to obtain male sperm months before oviposition. This study reveals the ability of captive female Red-legged Salamanders, Plethodon shermani (Plethodontidae), to store and retain viable sperm for long periods of time. By staging male–female courtship trials, we found that a female’s retention of the male sperm mass is visible in her cloaca for up to 4 d (X̄  =  2.8 d). Given the prolonged breeding season exhibited by this species (>10 wk), it is unlikely that the sperm mass functions efficiently to prevent female remating in that season. In addition, oviposition and egg-rearing in the laboratory revealed that P. shermani females can store viable sperm in their sperm storage organs (spermathecae) for ≥9 mo. Histology and microscopy showed that a subset of females even retained sperm in their spermathecae after oviposition, but significantly less of their lumina were occupied by sperm compared with the lumina of females that did not oviposit. Finally, we documented that one captive female stored sperm in her spermatheca from an insemination that occurred 17 mo earlier. Thus, sperm from one breeding season may have the potential to interact with sperm obtained in a prior breeding season, which is a finding that has implications for the evolution of postcopulatory sexual selection in this species.

Individual size is an important determinant of the outcomes of inter- and intraspecific interactions. Different-sized members of a guild might represent prey, competitors, or predators. Although direct predation rates might be low, trait-mediated indirect effects of predators on prey can yield altered activity, microhabitat use, survival, and growth. If individuals respond to all sizes of a predator regardless of the predation threat, antipredator behaviors might incur costs for prey as they forgo foraging opportunities or experience predation by other predators. Accurate assessment of predation risk would minimize costs resulting from antipredator behavior. We evaluated the ability of larval salamanders to assess predation risk and alter their habitat selection in response to intraguild competitors and predators. Specifically, we assessed behavioral responses to the presence of a conspecific, a similarly sized heterospecific, and a small or large individual of a predatory species. We predicted that larval salamanders would select habitat differently in the presence of a large predatory heterospecific, but not in the presence of similarly sized heterospecifics or conspecifics. The focal species occupied habitat 29 ± 0.02% farther from a large heterospecific predator than from small heterospecifics, even if the heterospecifics were smaller individuals of the predatory species. The focal species also exhibited escape behaviors only in the presence of the large members of the predatory species. These data indicate that salamander larvae can assess size-specific predation threats, minimizing predation risk through use of antipredator behaviors.

Animal populations that normally fluctuate in size in response to stochastic environmental events might be subject to unsustainably high mortality rates in the face of progressive habitat loss or degradation. This should perturb the population’s age-structure in predictable ways if the increase in mortality is age- or stage-specific (i.e., a decline in recruitment should result in a progressively older adult population, whereas a decline in adult survivorship should result in a progressively younger adult population). We used skeletochronology to ascertain the ages of adult individuals in a population of Fowler’s Toads, Anaxyrus ( =  Bufo) fowleri, over 20 yr, spanning a period of regulated population fluctuation from 1992 to 2002 and a period of sustained population decline thereafter until 2011. Age structure was similar between sexes, but was highly variable during both periods. Although there was no temporal trend detected in average age among 420 toads during the predecline period, 1992–2000, there was an increase in average age among 469 toads during the decline period, 2002–2011, with no significant change in adult survivorship. This evidence of an aging population is consistent with a reduction in recruitment in the population, related to the progressive loss of breeding habitat caused by an invasive plant, demonstrating that amphibian populations may be threatened with decline even when mortal threats to adults have not increased.

In oviparous species, preovulatory maternal effects such as investment in yolk quantity and composition or levels of yolk steroid hormones might potentially affect hatchling body sizes, growth rates, performance, and sex in species with temperature-dependent sex determination. We investigated the effects of egg mass and levels of testosterone and 17β-estradiol in the yolk on the phenotypes of hatchling Magdalena River Turtles (Podocnemis lewyana) in three populations in the Magdalena River drainage of northern Colombia. We hypothesized that, under homogeneous incubation conditions, the differences documented among clutches would be attributable to familial effects, caused by either heritable genetic factors or preovulatory maternal effects. Eggs were incubated artificially at the pivotal temperature for the species (33.4°C) and hatchlings were reared in the laboratory for 2 mo. Two eggs from each clutch were tested for testosterone and 17β-estradiol levels. Sex ratios, hatchling size, mass, and righting times varied both between clutches within a site and between populations. Egg mass was positively related to hatchling body size and mass, both at hatching and at 2 mo of age. Levels of 17β-estradiol concentrations influenced hatching success rates and incubation periods. Sex ratios were marginally related to 17β-estradiol levels, with clutches and sites with higher levels tending to produce fewer males. Our results provide evidence that preovulatory maternal effects play a role in influencing phenotypic attributes related to hatchling survivorship such as size, growth rate, and performance, and also seem to interact with incubation temperature to determine the sex of each individual and the sex ratio of the clutch, which has implications for both parental and offspring fitness.

Timber Rattlesnakes, Crotalus horridus, are an endangered species in New Jersey, where high human population density places extraordinary pressures on natural populations. Disjunct populations are found in both the northern part of the state and a few scattered locations in the southern Pine Barrens. The Pine Barrens populations were previously shown to have reduced levels of genetic diversity compared to other populations in the Mid-Atlantic region. In this study, we used microsatellite DNA to examine the remaining six known C. horridus populations in the Pine Barrens and two in the northern part of the state. Bayesian analysis, genetic distance analysis, and factorial component analysis were performed, and the results indicated that the sampled populations represented four genetic subgroups, the two northern populations comprised one subgroup and the remaining six Pine Barrens populations comprised the other subgroups. Although there was evidence for isolation by distance among the Pine Barrens populations, geographic distance alone did not account for a substantial amount of among-group variation. The combined analyses implicated paved roads as primary isolating barriers between populations. Given their geographic isolation and reduced levels of genetic diversity, intensive efforts may be required to ensure the persistence of the behaviorally and genetically unique C. horridus populations of the New Jersey Pine Barrens.

The level of species richness of amphibians found in Brazil is the greatest in the world. Despite increasing anthropic pressures on the Brazilian Cerrado and Amazon biomes, several new anuran species are described each year. In this study, two new species of Rhinella found in Brazil are described and assigned to the Rhinella margaritifera species group, based on morphological features. Rhinella sebbeni sp. nov. occurs in forested environments in the Cerrado biome and is characterized by the combination of the following features: snout–vent length (SVL; range  =  48.5–59.7 mm in males, and 54.7–66.7 mm in females); presence of bony protrusion at the angle of jaws and rostral keel at the tip of snout; skin on the dorsum with a few granules, but more concentrated on the flanks; parotoid gland is well delineated and small and elliptical in shape showing a lateral line of tubercles. Rhinella gildae sp. nov. is found in southern Amazonia and is characterized by the combination of following features: SVL (range  =  69.6–76.4 mm in males); cephalic crests poorly developed; parotoid gland without lateral line of tubercles; in dorsal view, supratympanic crest not exceeding the angle of the jaws; and presence of a vertebral line. We discuss data on morphological variation, natural history attributes, and distribution of the two new species.

I describe a new species of frog of the Hylarana signata species complex from Mt. Busa, Sarangani and South Cotobato provinces, southern Mindanao Island, Philippines. The new species is distinguished from all other members of the H. signata complex by a unique combination of characters of external morphology, biochemical allelic variation, and the species’ position in phylogeny, estimated by analysis of multilocus DNA sequence data. Justification for recognition of the new species is further supported by marked sequence divergence in mitochondrial and nuclear genes. The new species has been collected only once in >20 yr despite targeted survey efforts on Mindanao, and multiple possible explanations are available to explain its extreme rarity. The recognition of this species, on the basis of a single previously misidentified specimen, accentuates the importance of collecting large sample sizes of specimens during faunistic surveys. Recognition of a new species from a locality that has now been heavily disturbed by commercial logging also emphasizes the extreme conservation importance of the last remaining forest fragments in the southern Philippines.

We describe a new species of the genus Rabdion based on morphological evidence. The new species, Rabdion grovesi sp. nov., is restricted to South Sulawesi, whereas Rabdion forsteni is widely distributed on the rest of Sulawesi (Indonesia). Rabdion grovesi sp. nov. differs from R. forsteni by having a broader, shallower, and rounded rostral (vs. narrow, deep, and pointed); nasal touched by first and second supralabials (vs. first only); temporals 1 2 (vs. 1 3); 192 ventrals (vs. 130–157 in males and 152–160 in females); elongate (vs. shorter) dorsal scales; and a bluish gray dorsum (vs. grayish brown) in preservative. Finally, we provide a complete redescription for R. forsteni based on the subadult female syntype, MNHN 7210.