It was a rainy night on the 6th of July in the year 2015. A group of 15 frog enthusiasts were up and about as part of the citizen engagement initiative known as “Bisle Frog Team”. We were poised to walk on a specific trail and count the number of frogs seen there. Five minutes into the walk, Shashwat, one of the participants, signaled towards my friend Gururaja KV and me asking us to come over and have a look. He had stumbled upon an arthropod of the genus Scutigera feeding on a juvenile Western Tree Frog (Polypedates occidentalis). The Scutigera sp, commonly called the House Centipede was found on a rock and had started to ingest the anuran by its left eye. Our presence did not disturb the Scutigera sp. and it continued to feed on the anuran. We made observations for about five minutes and continued on our survey. We did not even wait to see if the whole anuran was consumed.
We were near the community hall in the small village of Bisle in Sakleshpura Taluk, Hassan. The place is surrounded by evergreen forests and rice paddy fields and the region receives a mean annual rainfall of around 5000 mm. During the walk, we observed over six adult Western Tree Frogs around the pond and they were actively vocalizing and feeding. There are no published natural history details about the tadpoles of this species. The adult males of these tree frogs range up to 55 mm and females measure up to 70 mm. They are known to breed in the Western Ghats during the southwest monsoon ranging from June to September.
We were unsuccessful in determining the identity of the Scutigera sp. as they are an under-studied taxon in India. However, most members of Scutigera sp. are common in the forests and in households in both the Western Ghats and other parts of India and like other members of the genus, have venom glands. The anuran we spotted did not show any signs of movement and was possibly bitten.
Predation poses a strong constraint on anuran (frogs and toads) populations. Anurans are known to be most vulnerable to invertebrate predators either when they are breeding or while they are juveniles. There is only one report that is over a decade old, synthesizing the predation of anurans and lists a diverse community of 68 species of anurans being predated in 300 instances by at least 57 species of invertebrates (Toledo, 2005. Herpetological Review 36: 395–400).
We seldom notice predation events and we know little about even the broad categories of predators, particularly among invertebrates. This observation emphasizes the need to document behaviors and interactions among predators and prey among amphibians and across life stages. Predation poses significant pressures on the fitness of an organism and is known to be a key driver of the evolution of reproductive behaviour such as parental care among amphibians.
The Western Ghats of India has a rich diversity of amphibians where new species continue to be described. Natural history forms the basis for understanding ecology. There is great potential to undertake experimental studies to understand how predation affects larval amphibians and may help in uncovering predator avoidance mechanisms.