Search

Night frogs of the genus Nyctibatrachus are endemic to the Western Ghats of southern India, and these frogs exhibit unique courtship and spawning behavior. Herein, we studied the breeding biology of Nyctibatrachus humayuni and describe its tadpole. Our results show that N. humayuni is a terrestrial breeder that reproduces during the southwestern monsoon. Adults of N. humayuni are sexually dimorphic: females are larger, and males have femoral glands on the ventral surface of their thighs. The operational sex ratio is highly skewed in favor of males during the breeding season, while it is close to 1:1 during the rest of the year. Males choose suitable spawning sites, establish territories, and initiate calling, whereas females approach the vocalizing males and, following a brief courtship, deposit eggs at the sites chosen by males. Males produce amplitude-modulated advertisement calls consisting of single or multiple notes depending on the social situation. Unlike most frogs, females of N. humayuni do not spawn while in amplexus. Instead, spawning occurs after separation of the pair following a brief 'abbreviated amplexus.' Eggs are deposited on the moist rocks, boulders, and muddy surfaces in the middle and along the sides of montane streams. Clutch size is larger during the early breeding season, while it decreases with the season's progression. Interestingly, egg size is comparable among the breeding season phases, suggesting the absence of a trade-off between egg size and clutch size. Tadpoles are moderately oval and dorsoventrally flattened with a blunt snout. The mouth is ventral; the oral disc consists of upper and lower labia and jaw sheaths. Teeth are completely absent; the jaw sheaths are keratinized and serrated. The upper and lower labia are surrounded by a single row of marginal papillae and 2-3 rows of sub-marginal papillae. [ABSTRACT FROM AUTHOR]

Pattern of mating, spawning behavior, and sexual size dimorphism were studied in the Indian Common Toad, Bufo melanostictus. Male and female B. melanostictus are sexually dimorphic in size. Adult males are significantly smaller than adult females, and the ratio of body size of females to males was 1:19. For breeding, the majority of males and females segregated on the basis of their size; larger males paired with larger females leaving smaller males to pair with smaller females. A positive correlation between the body sizes of mating partners provided evidence of size-assortative mating. Successful males were larger in length than their unsuccessful competitors. Operational sex ratio was skewed in the favor of males. A stereotypical spawning behavior was observed: At the initiation of spawning by the female, the male juxtaposed his cloaca with that of the female's followed by a few seconds of rigorous toe movements. Spawning was completed within 2-5 h. Subsequently, the female exhibited pseudo-spawning behavior once or twice. In the absence of more eggs, the male quickly released his clasp, and the pair separated. The selection of mating partners in amphibians depends Wells, 2007). Contrary to the earlier belief that nonrandom [ABSTRACT FROM AUTHOR]

Frogs of the genus Nyctibatrachus (family Nyctibatrachidae) exhibit a unique reproductive behaviour. They may completely lack or have an abbreviated amplexus, deposit terrestrial eggs and even offer paternal care. We studied the courtship and spawning behaviour of Nyctibatrachus humayuni from Matheran located in the northern region of the Western Ghats of India. The breeding season of N. humayuni coincides with the onset of south-west monsoon. Adult males vocalise from their calling sites on wet rocks/dead logs that often harbour egg clutches and females approach the calling males, resulting in a loose cephalic amplexus that lasts up to 10 minutes. The male dismounts and sits aside; then the female deposits the eggs and moves away from the spawning site or into the water. The mean clutch size and the egg diameter are found to be 30.3 ± 1.89 and 2.44 ± 0.04 mm, respectively. Once the female moves away following spawning, the male slowly moves on to the eggs and fertilises them. The males of N. humayuni appear to be territorial and offer parental care by attending the eggs only during night. Paternal egg attendance most probably reduces the risk of predation by nocturnal predators. [ABSTRACT FROM AUTHOR]