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.

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Successful survival and reproduction of prey organisms depend on their ability to detect their potential predators accurately and respond effectively with suitable defences. Predator detection can be innate or can be acquired through learning.We studied prey-predator interactions in the larval bronzed frogs (Sylvirana temporalis), which have the innate ability to detect certain predators. We conducted a series of experiments to determine if the larval S. temporalis rely solely on innate predator detection mechanisms or can also learn to use more specific cues such as conspecific alarm cues for the purpose. The results of our study clearly indicate that larval S. temporalis use both innate and learned mechanisms for predator detection. Predator-naive tadpoles could detect kairomones alone as a potential threat and responded by reducing activity, suggesting an innate predator detection mechanism. Surprisingly, predator-naive tadpoles failed to detect conspecific alarm cues as a potential threat, but learned to do so through experience. After acquiring the ability to detect conspecific alarm cues, they could associate novel predator cues with conspecific alarm cues. Further, post feeding stages of larval S. temporalis are sensitive for learning to detect conspecific alarm cues to label novel predators.

Length-weight relationships (LWRs) are reported for four freshwater fishes from the Koyna and Nira Rivers of northern Western Ghats of India. Specimens were collected using the cast and gill net (3.5-7.5 cm mesh size) during June 2017 to July 2018. The b values for LWRs varied from 2.941 to 3.336 (r 2 >0.96 and p < 0.0001 for all species).New maximum total length was recorded for Hypselobarbus kolus, which is presently categorized as vulnerable. The results provide baseline information for the sustainable management and conservation of the studied species.

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