Reproductive cycle, sexual maturity and longevity of Odontophrynus americanus (Anura: Odontophrynidae) in South Brazil

Abstract

Studies on the reproductive biology and age of amphibians provide primary information about the life history and population demographic parameters of species. Here, we describe the reproductive cycle, size–fecundity relationships, reproductive effort, sexual dimorphism and sexual maturity of Odontophrynus americanus, the flood frog, from South Brazil. A total of 96 individuals were analysed. The reproductive cycles of males and females were described through morphoanatomical analysis of testis and ovary. Age at onset of sexual maturity and estimated longevity were determined by skeletochronology. Individuals of O. americanus presented a potentially continuous reproductive cycle with a peak of reproductive activity in the warmer months. Females presented a higher reproductive investment than males. Sexual maturity was reached at around one year of age for both sexes while longevity differed between the sexes, with females living up to six years and males up to ten years. No evidence of sexual size dimorphism was found. This study is among the few that have assessed age at sexual maturity and longevity in a Neotropical anuran. Basic aspects of life history are of paramount importance because they allow comparisons and test of hypotheses to be made, which can help to build generalizations about the evolutionary meaning of ecological strategies.

Smaller size of harlequin toads from populations long exposed to the fungal disease chytridiomycosis

“…This suggests that males from extant populations are breeding 1 year earlier compared to those from pre‐epidemic populations. Although growth curves for A. cruciger females are lacking, in many tropical and mid‐elevation anurans males mature slightly earlier or at the same age than females (Duellman & Trueb, 1994; Morrison & Hero, 2003; Sinsch & Dehling, 2017) but females usually grow faster (Brum et al, 2022; López et al, 2017; Sinsch & Dehling, 2017). Similarly, A. zeteki females raised in captivity tend to grow faster than males (Edgardo Griffith, personal communication).…”

Recovery and Characterization of Spermatozoa in a Neotropical, Terrestrial, Direct-Developing Riparian Frog (Craugastor evanesco) through Hormonal Stimulation

“…Spermatogenic cycles inside testicular cysts (intra-cystic) are mostly synchronous in anurans; nevertheless, some studies have shown the existence of spermatogenic intracystic asynchronicity in some species [48,49]. A possible explanation for the presence of more than one sperm production peak could be intracystic asynchronicity, where different cysts are at different spermatogenic stages [21,50] at a given time, causing an asynchronous release of high concentrations of mature spermatozoa after hormonal stimulation once the cycle is completed (i.e., peaks). This, coupled with variations in the swelling response of Sertoli cells that promotes the expulsion of mature spermatozoa from these cells into the lumen [51] after hormonal stimulation, could explain the presence of sperm concentration peaks.…”