Trophic Niche Partitioning between Sympatric Naja naja and Ptyas mucosa: Crowdsourced Data in Application to Community Ecology

Abstract

Abstract. Spectacled Cobras (Naja naja) and Oriental Ratsnakes (Ptyas mucosa) frequently share habitats and presumably occupy a similar trophic niche. We present a dietary synopsis of both species as well as niche metrics based on feeding events retrieved from crowdsourced data. Our analysis suggests a high importance of ophiophagy in the diet of N. naja, which occasionally feeds on mammals and frogs, but rarely on other taxa. Ptyas mucosa preyed most frequently on frogs and occasionally on snakes and mammals. The relative importance of shared prey items was generally high and confirmed overlap of their trophic niches. Interspecific trophic competition could serve as a noninvasive conservation tool. In particular, adult N. naja may avoid areas in which size-equivalent or size-superior P. mucosa are present, potentially offering new perspectives on common conservation practices for this medically significant snake. Methodological biases because of low detection probability of subterranean predation events and a bias in ophiophagous events in data retrieved from social media cannot be ruled out. Two key issues need to be considered when using crowdsourced data to assess trophic niche partitioning: 1) choosing an appropriate level of prey identification as a base for meaningful comparison and 2) ensuring relative spatial homogeneity of data origins over the common range. When considering the trade-off between data quality and quantity for comparative analysis, crowdsourcing is a valuable but supplementary resource for studies of niche partitioning in sympatric species. The presented data expand the known dietary spectrum of both snake species by 42 previously unpublished trophic interactions.