Gammarus aequicauda (Amphipoda) and two different prey species: Is the ability of a predator to learn important?

Abstract

Individual experience contributes to total functional biodiversity in every aquatic ecosystem. However, the learning ability and individual memory of crustaceans are issues that remain poorly understood. The influence of individual experiences on the feeding behavior of the predator Gammarus aequicauda (Amphipoda) was studied experimentally. The predator was acclimated and allowed to feed on one of the alternative prey – chironomid larvae Baeotendipes noctivagus or anostracan parthenogenetic Artemia in studies from 3 to ten days. They were then placed in a vessel with both species of prey. We then measured the time spent on the main stages of the feeding process: searching for food before capturing prey, prey handling time, and subsequent digestion. If experiments were conducted in the presence of both prey species, the feeding behavior characteristics (searching and handling time) of G. aequicauda, which had previously fed on chironomid larvae, differed significantly from those of Gammarus, which had previously fed on Artemia. Acclimation of G. aequicauda to feed on chironomid larvae can significantly reduce the time spent on searching, capturing, and handling of chironomids. Acclimation of G. aequicauda to feed on Artemia led to smaller changes in time spent on capturing, and handling of Artemia. The effects of experience on foraging efficiency increased in both variants of acclimation.