Predation and prey preference of the exotic snail Anentome helena on two freshwater snails: implications for species invasion

Abstract

Aim: The aim of the present study was to estimate the probable impact of predation of the exotic snail Anentome helena on two co-occurring freshwater snails, Racesina luteola and Physella acuta, in the laboratory set-up. Methodology: In the initial experiment, the predatory efficiency of A. helena was observed using R. luteola and P. acuta as prey, separately, under varying prey and predator densities. In the following experiment, the prey snails were provided in both conspecific and heterospecific conditions with different predator densities to deduce the prey preference of A. helena, if any. Results: The experiments show that A. helena can consume a considerable number of R. luteola and P. acuta. The predation rate of A. helena varied significantly (p< 0.0001) with different sizes of prey, prey and predator densities. Although the predation rate differed among conspecific and heterospecific prey conditions, A. helena did not demonstrate any significant prey preference towards any of the prey. Interpretation: The study revealed that the chance dispersal of predator A. helena from household aquaria to natural habitats may directly impact the population of the freshwater snail R. luteola and P. acuta.