We report the crepuscular hunting behavior by the Besra Accipiter virgatus, on the Glossy Swiftlets Collocalia esculenta affinis and the Edible-nest Swiftlets Aerodramus fuciphagus inexpectatus in urban areas the Andaman & Nicobar Islands. Unlike other raptors in the islands, the Besra hunts at twilight often in the absence of moonlight or/and artificial light. Glossy and Edible-nest Swiftlets have been ranched in human habitations and their nests harvested for livelihood support of local communities under an ex situ conservation program. Using the focal animal sampling method, we recorded the hunting behavior of the Besra (the predator) on the swiftlets (the prey) for 40h (120 min/day for 20 days) at the ex situ swiftlet colony established in a house in the Middle Andamans. The Besra made 84 hunting attempts, with the highest success rate (15.4%) between 17.00–18.00 h. The catch rate was a mean of 4±11 (SD) per day. The maximum time that was used for attempt to kill the prey was two hours. Depredation of the Edible-nest Swiftlet by the Besra could affect ex situ conservation efforts, which can also lead to economic losses and retaliation against the raptor. Restricting perch sites for the raptor around ranching houses might reduce predation risks for the swiftlets.
Cave-dwelling organisms share different ecological and evolutionary relationships with caves. Based on these interactions, they are categorized as troglobites, troglophiles, and trogloxenes. In India, caves are meagerly explored, and thus cave study is in its infancy in India. Through the present study, we attempted to understand and model the distribution of crickets (Family Phalangopsidae), a critical group of insects - being the primary consumers in the cave ecosystems. We sampled seven caves using belt transects (N = 184; total area covered = 1294.9 m2) with 1 m width. During the survey, we encountered 818 individual crickets (116.85 ± 47.16 SD per cave). Of these, 87.7% encounters were on walls, 7.09% were on the ceiling, and 5.13% were on the cave floor. We used the Single-species Multi-season occupancy model to calculate the overall, zone-wise, and cave-specific occupancy. Cricket occupancy in Baratang caves is seasonal and highly zonal, with detectability ≤1. The cave with less distinct zones has more consistent occupancies and zero chances of extinction and colonization. Hence, these caves serve as suitable habitat for the source population. A negative correlation of cave morphometric features (cave volume, wall surface area, and floor surface area), and density of crickets (p < 0.05), might need further validation. The study shows the need for detailed studies regarding cricket taxonomy and ecology towards establishing the conservation importance of the species and their habitat in the islands.
Caridina ravisankarani sp. nov. is a cave-adapted species, collected during June and November 2018 and January 2019 from a limestone cave (CN2) on Interview Island, Andaman and Nicobar Islands. The shrimps were collected from a stream, sourced through the percolation of rainwater, which reduces during the post-monsoon months. The species is closely related to Caridina typus H. Milne Edwards, 1837, Caridina villadolidi Blanco, 1939 and Caridina jeani Cai, 2010. A detailed comparison of characters and a key for identification are given in the text. The present species can be diagnosed by the presence of: short rostum with edentulous upper margin and ventral margin with 2 minute teeth situated at the distal part; outer antennular flagellum with 16 segments at the basal part swollen; highly atrophied propodus and dactylus of endopod of 2nd maxilliped; bushy long setae on fingers of 2nd chelate legs; dactylus of 5th pereopod with 42–43 comb-like bristles; dieresis with 18 spines; dorsal surface of telson with 4–5 pairs of spines and disto-median region doesn’t end in a point, outer lateral pair of spines absent and eyes with cornea pigmentation variable, from totally absent to a small black spot. Fecundity is 1300 eggs with an average length 0.71±0.03 mm and width 0.42±0.03 mm (Mean±SD).
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