Comparisons of spatial and temporal variation in demographic rates are crucial to understanding population dynamics. Yet, even well-studied species are often lacking in comparisons of such variability in demographic data, making these contrasts imperative to conduct in population ecology research. We conducted a long-term monitoring study of Spotted Salamanders (Ambystoma maculatum) at five ponds in Missouri, USA. We sampled populations using drift fences, and monitored breeding immigration dates, adult population sizes, sex ratio, juvenile recruitment, metamorph sizes, and metamorph emigration dates. Generally, we found that our study populations exhibited characteristics similar to other populations across their distribution. We also found spatial and temporal variation among populations in nearly all demographic parameters, however, indicating that multipopulation and multiyear studies will likely improve our inferential abilities in understanding population dynamics. We observed an overall positive relationship between metamorph size and date of metamorphosis, but this pattern was not consistent across ponds or years, indicating that different environmental pressures might influence selection on these traits. Finally, we identified rainfall amounts and frequency as the primary factors that influenced adult and metamorph movement patterns to and from ponds. Overall, the spatial and temporal variation in demographic data we provided can be useful for population modeling or conservation planning, in addition to furthering our understanding of population ecology of Spotted Salamanders.

Animal activity patterns can be influenced by selection pressures from local environmental conditions that might fluctuate at different temporal scales. Although studies with frog species and local populations can suggest how variation of environmental factors affects activity patterns, this topic has received little coverage for Neotropical diurnal frogs that inhabit streams, particularly for subtropical species. We described the temporal patterns of calling activity of Schmidt's Spinythumb Frogs (Crossodactylus schmidti) in southern Brazil and investigated the role of environmental factors on this activity. We recorded local environmental variables and monitored calling activity from October 2011 to September 2012, by counting the number of calling males and the number of emitted calls at hourly intervals throughout the day. Male frogs engaged in calling activity year-round, despite the local climatic seasonality. There was no seasonality in the number of calling males or in the number of calls; moreover, variation in photoperiod did not affect the duration of the calling activity throughout the year. Crossodactylus schmidti showed a predominantly diurnal calling activity, with a spike in the early morning followed by a gradual increase in activity during daytime hours, and a subsequent decrease in activity at dusk. Environmental factors had varying effects on calling activity: (1) monthly activity was positively associated with accumulated rainfall and air temperature; (2) early morning activity was greater when air temperatures were higher; and, (3) daytime calling activity was positively associated with light intensity. Whereas our results do not preclude the effect of other environmental factors in the calling behavior of male C. schmidti, accumulated rainfall, air temperature, and light intensity appear to be abiotic regulators of this activity at the analyzed temporal scales. We discuss the biological implications of these environmental factors in the calling activity and reproduction of C. schmidti, and compare the observed patterns with those of other taxa of diurnal stream-breeding frogs.

Os padrões de atividade animal podem ser influenciados por pressões seletivas de condições ambientais locais que podem flutuar em diferentes escalas temporais. Embora estudos com espécies de anuros e populações locais podem sugerir como a variação de fatores ambientais afeta os padrões de atividade, este assunto tem recebido pouca cobertura para anuros diurnos neotropicais que habitam riachos, particularmente para espécies subtropicais. Nós descrevemos os padrões temporais da atividade de vocalização de uma rã diurna de riacho (Schmidt’s Spinythumb Frogs, Crossodactylus schmidti) no sul do Brasil e investigamos o papel dos fatores ambientais sobre esta atividade. Nós registramos variáveis ambientais locais e monitoramos a atividade de vocalização entre outubro de 2011 e setembro de 2012, através da contagem do número de machos em atividade de canto e do nú mero de cantos emitidos em intervalos de uma hora ao longo do dia. Os machos estiveram em atividade de vocalização durante todo o ano, apesar da típica sazonalidade climática local. Não houve sazonalidade no número de machos ativos ou no número de cantos emitidos; além disso, a variação no fotoperíodo não afetou a duração da atividade de vocalização ao longo do ano. Crossodactylus schmidti apresentou uma atividade de canto predominantemente diurna, com um pico no início da manhã seguido de um aumento gradual da atividade durante o dia, e uma subsequente diminuição da atividade ao anoitecer. Os fatores ambientais tiveram efeitos variáveis sobre a atividade de vocalizaçã o: (1) a atividade mensal foi positivamente associada à precipitação acumulada e à temperatura do ar; (2) a atividade do início da manhã foi maior quando as temperaturas do ar eram mais altas; e, (3) a atividade diurna foi positi

The aquatic pathogen Batrachochytrium dendrobatidis (Bd) can cause declines in amphibian populations and species extinctions worldwide. In tadpoles, epizootic events have not been reported; however, there is a possibility for rapid spread of disease in water. Here, we quantified Bd infection dynamics in tadpoles from two streams in the northeastern Atlantic forest of Brazil. Bd prevalence varied seasonally and increased during the rainy season. Aplastodiscus sibilatus and Proceratophrys renalis tadpoles were Bd positive in both seasons, whereas Agalychnis granulosa tadpoles were Bd positive only during the rainy season. Bd prevalence was higher in A. sibilatus than in A. granulosa and P. renalis. We found that larger individuals have a higher probability of being Bd positive, independent of the developmental stage. Moreover, we found that canopy cover, water flow, water temperature, water depth, and pH were associated with Bd prevalence. Our results highlight the fact that tadpoles can serve as pathogen reservoirs; therefore, monitoring anuran larvae populations in these habitats can enhance the impact assessment of this pathogen in biodiversity hot spots.

In rasping aquatic feeders, like many tadpoles, it is challenging to measure both the food consumed and excreta produced and thereby calculate digestive efficiency. The goals of this study were to measure the apparent digestive efficiency of Northern Leopard Frog (Lithobates pipiens) tadpoles on an artificial laboratory diet and test the use of putative inert markers to calculate digestibility. The diet used was commercial ground rabbit chow (primary ingredient: alfalfa meal) suspended in agar and gelatin. If dietary ash (8.35% of diet dry mass) were a perfect inert marker, then its concentration in digesta, excreta, or both, should increase as organic matter is absorbed from the food, making the ratio of ash in food to ash in digesta or excreta an index of how much of the food mass is indigestible. Ash content in digesta dissected from the distalmost portion of the tadpoles’ intestine was about twice as concentrated as in food, indicating a 50% dry matter digestibility (DMD). This compared well with a DMD value based on our direct measurement of food intake and excreta production (50 ± 5%), which did not vary with Gosner stage (Stages 33–41 tested). Excreta collected from the bottom of the holding tank did not yield accurate estimates of DMD. We conclude that total ash of food and digesta can be used to measure DMD when L. pipiens is offered this diet.

Little is known about behavioral aspects of tadpole feeding ecology. Resource protein is by far the most studied factor assumed to govern food choice in tadpoles, whereas other factors such as resource toughness and competition have received less attention. Here, we tested the food choice of an omnivorous pond-dwelling tadpole when exposed to animal and algal materials at different toughnesses and concentrations (1× and 2× amount of food per volume), used as a proxy indicator of energy gain per bite. We subsequently tested how tadpole feeding behavior and food choice change with competitor density (when alone, in pairs, or in a group). We found that type, toughness, and concentration of the food influenced choice by the tadpoles; however, a three-way interaction among these variables was absent. The tadpoles did not feed randomly and preferred the algal materials when these were softer than, or as tough as, the animal materials. The tadpoles discriminated among foods of different concentrations and readily fed on the high-concentration food materials. Tadpole feeding behavior was density dependent. In a group, the tadpoles nearly doubled their feeding activities and increased their feeding on animal materials, here the less-preferred foods. Food toughness, energy gain per bite, and the presence of competitors influence tadpole feeding behavior, and could be factors used as proximate cues for determining food quality in tadpole foraging strategies.

We investigated phenotypic diversification in the species-rich and ecologically diverse turtle families Emydidae and Geoemydidae. In particular, we were interested in whether these groups, with many ecologically and morphologically similar species, show similar patterns of evolutionary radiation. We focused on directions of evolution and evolutionary allometry; we also quantitatively investigated whether two supposed morphological analogs shared within the two groups (e.g., “Box Turtles” and “Wood Turtles”) show evidence of convergence. A set of 53 three-dimensional landmarks were digitized on 1029 turtle shells representing 50 emydid species and 62 geoemydid species. These data were analyzed using standard geometric morphometric techniques. Evolutionary patterns were assessed using tests for phylogenetic signal, and the relationship between size and shell shape was determined via phylogenetic regression. Tests for phylogenetic signal in shell shape and for allometry both yielded significant results. Three hypothesis testing methods were applied to determine whether the supposed morphological analogs in the emydid and geoemydid families exhibited convergence. Although there was no evidence of shared adaptive peaks among either Box Turtles or Wood Turtles, there was evidence in both groups that their members have evolved to be more similar to each other compared to their ancestors than would be expected by chance. Thus, although both Box Turtles and Wood Turtles each show modest convergence, most of the evidence indicates a complex pattern of convergence and differentiation within both groups. Similarities in certain aspects of morphology or ecology might be overshadowing biologically meaningful variation within these morphological analogs.

Native to the southeastern United States, Southern Watersnakes (Nerodia fasciata) are known from two sites in California, but their ecological impacts are poorly understood. We investigated the ecology of Southern Watersnakes in Machado Lake, Harbor City, Los Angeles County, California, including an assessment of control opportunities. We captured 306 watersnakes as a result of aquatic trapping and hand captures. We captured snakes of all sizes (162–1063 mm snout–vent length [SVL], 3.5–873.3 g), demonstrating the existence of a well-established population. The smallest reproductive female was 490 mm SVL and females contained 12–46 postovulatory embryos (mean  =  21). Small watersnakes largely consumed introduced Western Mosquitofish (Gambusia affinis), while larger snakes specialized on larval and metamorph American Bullfrogs (Lithobates catesbeianus) and Green Sunfish (Lepomis cyanellus). Overall capture per unit effort (CPUE) in traps declined with time during an intensive 76-d trapping bout, but CPUE trends varied considerably among traplines and it is unlikely that the overall decline in CPUE represented a major decrease in the snake population size. Although we found no direct evidence that Southern Watersnakes are affecting native species in Machado Lake, this population may serve as a source for intentional or unintentional transportation of watersnakes to bodies of water containing imperiled native prey species or potential competitors.

We reassessed the taxonomic status of an Asian genus of arboreal bufonids, Pedostibes, based on examination of preserved material of the two species currently attributed to this genus. Analysis of their morphological, morphometric, and geographic distribution data revealed that Pedostibes tuberculosus, the type species of this genus from the Western Ghats, southwestern India, is morphologically distinct from the geographically separated member, P. kempi, which is distributed in northeastern India. Hence, the generic nomen Pedostibes is restricted to the type species, rendering it a monotypic genus from the Western Ghats of peninsular India. A re-examination and detailed comparisons of the types of P. kempi with other bufonid genera revealed morphological similarities with another geographically proximate toad, Bufoides meghalayanus, from northeastern India. Hence, this taxon is formally transferred herein to Bufoides with a redescription. The composition of the recently described Southeast Asian toad genus Rentapia is reevaluated and the name-bearing type specimens of the currently ascribed taxa are redescribed. A detailed examination of the types of Rentapia everetti and R. rugosa revealed morphological congruence coupled with geographic sympatry. Hence, the latter nomen is synonymized with R. everetti in accordance with the International Code of Zoological Nomenclature principle of priority.

A new species of Bachia of the B. heteropa group is described from the Parque Nacional Montanhas do Tumucumaque in northeastern Amazonia, Amapá State, Brazil. The new species morphologically resembles B. heteropa and B. guianensis. Nonetheless, the absence of interparietal and prefrontal scales, and the number of supraciliary scales, can distinguish the new species from its close relatives. This description increases the species diversity of the B. heteropa group after a number of decades of stasis in the taxonomy of this group in Amazonia. In addition, we present an updated key to the groups of Bachia, including the species and subspecies of the B. heteropa group.

Helicops is a genus of Neotropical watersnakes containing 16 species. Based on morphological (scale counts, dentition, coloration, and hemipenis anatomy) and genetic data (16S rRNA and C-mos genes), we identify a new species of this genus. The new taxon is diagnosed by having 17-17-15 dorsal scale rows; 111–117 ventral plates; 41–56 subcaudals without keels; nasal entire; 18–21 2 maxillary teeth; hemipenis bilobed, semicalyculate, and semicapitate; dorsum uniformly medium brown or dark brown; venter cream or light brown with two medial rows of black markings, usually semilunar in shape. The new species occurs from southeastern to northern Minas Gerais state, Brazil.