Body size, reproductive biology and abundance of the rare pseudoboini snakes genera Clelia and Boiruna (Serpentes, Colubridae) in Brazil

Pseudoboini snakes of the genera Clelia and Boiruna are apparently rare in nature and certainly rare in collections. This work presents data on body size, reproduction and abundance of five Brazilian species of these genera, in the largest collection of snakes in Latin America, the Instituto Butantan. Despite scarcity of data, follicular cycle seems to be continuous in most species, except Clelia rustica, which occurs in highlands. Females are larger than males in all species, and fecundity is low when compared to other pseudoboini. Abundance is very low for all species even considering 100 years of collecting, and it is decreasing in recent decades when compared to other snakes (Bothrops jararaca, Oxyrhopus guibei, O. clathratus, Philodryas patagoniensis, Sibynomorphus mikanii, and Spilotes pullatus). The studied species present at least five traits of commonly threatened species and require more attention in researches and conservation policies

Reproductive biology and food habits of Pseudoboa nigra (Serpentes: Dipsadidae) from the Brazilian cerrado

Neste trabalho fornecemos informações sobre tamanho corporal, dimorfismo sexual, ciclo reprodutivo e hábitos alimentares da serpente Pseudoboini Pseudoboa nigra, que ocorre no domínio do Cerrado na região central da América do Sul. Com base na dissecção de 147 espécimes preservados, mostramos que as fêmeas são em média maiores e atingem maturidade sexual com maior tamanho corporal que os machos. O dimorfismo sexual não foi significativo para o tamanho da cabeça, mas os machos possuem caudas relativamente mais longas que as fêmeas. A vitelogênese, a postura de ovos e a espermatogênese ocorrem durante todo o ano, e os machos não armazenam esperma no ducto deferente por longos períodos. A principal presa dessa espécie são lagartos; não há evidências de variação ontogenética ou de diferenças relacionadas ao sexo na dieta dessa espécie.Herein we provide data on body size, sexual size dimorphism, reproductive cycle, and food habits of the pseudoboini snake Pseudoboa nigra, which is distributed mainly in central South America throughout the Cerrado domain. Based on dissections of 147 preserved specimens, it is shown that females attain, and mature at, larger body sizes than males. There is no significant sexual dimorphism in head length, but males have longer tails relative to their body sizes. Vitellogenesis, egg-laying, and sperm production occur throughout the year, but males do not exhibit long-term sperm storage. The main prey of P. nigra is lizards; there is no evidence of ontogenetic change or sex differences in the diet of this species

Life-history Adaptations To Arboreality In Snakes.

If selective forces on locomotor ability and reproductive biology differ among habitats, we expect to see relationships between habitat, morphology, and life-history traits. Comparative (phylogenetically based) analysis of data from 12 pythonid and 12 boid snake species reveals multiple evolutionary shifts in habitat use, notably in the evolution of arboreal habits. Compared to terrestrial and aquatic taxa of the same overall body size, arboreal species have narrower and more laterally compressed bodies and relatively longer tails. Offspring sizes are not affected by arboreality, but presumably reflecting space constraints within their narrow bodies, arboreal species (1) produce smaller clutch sizes relative to maternal body length and (2) have left and right ovaries that overlap little if at all along the length of the body (i.e., the right ovary is positioned anterior to the left ovary) whereas in terrestrial snakes the two ovaries overlap along much of their length. This modification of ovarian morphology in arboreal snakes presumably reduces the degree of bodily distension during vitellogenesis and pregnancy, thus enhancing climbing ability and camouflage among the branches.88359-6

Quantifying Anuran Microhabitat Use to Infer the Potential for Parasite Transmission between Invasive Cane Toads and Two Species of Australian Native Frogs

<div><p>Parasites that are carried by invasive species can infect native taxa, with devastating consequences. In Australia, invading cane toads (<i>Rhinella marina</i>) carry lungworm parasites (<i>Rhabdias pseudosphaerocephala</i>) that (based on previous laboratory studies) can infect native treefrogs (<i>Litoria caerulea</i> and <i>L. splendida</i>). To assess the potential of parasite transmission from the invader to the native species (and from one infected native frog to another), we used surveys and radiotelemetry to quantify anuran microhabitat use, and proximity to other anurans, in two sites in tropical Australia. Unsurprisingly, treefrogs spent much of their time off the ground (especially by day, and in undisturbed forests) but terrestrial activity was common at night (especially in anthropogenically modified habitats). Microhabitat overlap between cane toads and frogs was generally low, except at night in disturbed areas, whereas overlap between the two frog species was high. The situations of highest overlap, and hence with the greatest danger of parasite transmission, involve aggregations of frogs within crevices by day, and use of open ground by all three anuran species at night. Overall, microhabitat divergence between toads and frogs should reduce, but not eliminate, the transmission of lungworms from invasive toads to vulnerable native frogs.</p></div

Finding a place to live:conspecific attraction affects habitat selection in juvenile green and golden bell frogs

Conspecific attraction plays an important role in habitat selection of several taxa and can affect and determine distribution patterns of populations. The behaviour is largely studied and widespread among birds, but in amphibians, its occurrence seems limited to breeding habitats of adults and gregarious tadpoles. The Australian green and golden bell frogs (<i>Litoria aurea</i>) have suffered considerable shrinking of their original distribution in south-eastern Australia since the 1970s. Currently, with only about 40 populations remaining, the species is considered nationally threatened. In natural conditions, these frogs are aggregated in the landscape and do not seem to occupy all suitable ponds within the occurrence area. To date, studies focusing on the frogs' habitat have failed in finding a general habitat feature that explains current or past occupancy. This led us to the hypothesis that social cues may play a key role in habitat selection in this species. Using two choice experiments, we tested the preference of juvenile green and golden bell frogs for habitats containing cues of conspecifics of similar size versus habitats without conspecific cues. Tested frogs did not show a preference for habitats containing only scent from conspecifics but did prefer habitats where conspecifics were present. Our results show that conspecific attraction is a determining factor in juvenile green and golden bell frog habitat selection. To our knowledge, this is the first time the behaviour is shown to occur in juvenile frogs in the habitat selection context. From a conservation management point of view, the behaviour may help to explain the failure of reintroductions to areas where the frogs have been extinct, and the non-occupation of suitable created habitats in areas where they still inhabit and develop appropriated management strategies

How to form a group:Effects of heterospecifics, kinship and familiarity in the grouping preference of green and golden bell frog tadpoles

Social aggregations are widespread among animal groups. They are relatively common in amphibian larvae, likely conferring protection against predators, advantages for microhabitat selection, foraging efficiency, and thermoregulatory efficiency. Group formation involves selection of individuals to group with by the other members, and several tadpoles are reported to recognise and prefer to aggregate with siblings or familiar individuals. In Australia, tadpoles of the endangered green and golden bell frog, <i>Litoria aurea</i>, are attracted to conspecifics and form schools. We conducted two choice experiments for captive breed tadpoles of this species to test their grouping preferences. Tadpoles preferred to aggregate with conspecifics to heterospecifics of a sympatric species; however, when conspecifics were absent they preferred to aggregate with the heterospecifcs than to remain alone. Tadpoles also preferred unfamiliar kin to unfamiliar non-kin conspecifics, but had no preferences between unfamiliar and familiar siblings. Once widespread in southeast Australia, the green and golden bell frog has suffered considerable declines and local extinctions in recent decades. Susceptibility to chytridiomycosis is likely the major threat for most remaining fragmented populations and the major challenge for reintroduction programs. The strong gregarious behaviour of this species may affect disease dynamics, especially chytridiomicosis that continues to threaten remaining wild populations

Nocturnal substrates used by the three anurans in NT and WA.

<p>Cane toads (<i>Rhinella marina</i> = black bars), Green Treefrogs (<i>Litoria caerulea</i> = light grey bars), and Magnificent Treefrogs (<i>L. splendida</i> = dark grey bars) were sampled in natural and anthropogenically disturbed environments. For radio-tracked animals, only a single record per tracking period was included for each individual.</p

Pianka Index of microhabitat overlap among invasive cane toads <i>Rhinella marina</i> (RM), and native frogs <i>Litoria caerulea</i> (LC) and <i>L. splendida</i> (LS) in Australia.

<p>Pianka Index of microhabitat overlap among invasive cane toads <i>Rhinella marina</i> (RM), and native frogs <i>Litoria caerulea</i> (LC) and <i>L. splendida</i> (LS) in Australia.</p