Original paper

Predation by macroinvertebrates on Heterocypris incongruens (Ostracoda) in temporary ponds: impacts and responses

Vandekerkhove, Jochen; Namiotko, Tadeusz; Hallmann, Ewelina; Martens, Koen

Abstract

We conducted laboratory experiments to assess the potential impact of different macroinvertebrate taxa on populations and individuals of the ostracod Heterocypris incongruens (Ramdohr, 1808) a common inhabitant of temporary ponds. Our data show that nymphs of the emperor dragonfly (Anax imperator Leach, 1815) and adults of the pigmy backswimmer (Plea minutissima (Leach, 1817)), and to a lesser extent adults of the common backswimmer (Notonecta glauca Linnaeus, 1758), can dramatically reduce population densities of H. incongruens, and potentially also alter the size structure of the populations. Direct and indirect interactions among predators significantly reduced the predation efficiency of predators when multiple predatory species were combined. In consequence, predation pressure estimates should not be based on predator densities in biotically diverse systems. We also demonstrate that the predation pressure on H. incongruens is reduced through behavioral adaptations, such as migration to the open water and reduction of swimming activity. These behaviors are induced by taxon-specific chemical cues.

Keywords

predationostracodshydroperiodmacroinvertebratesbehaviorpredator-induced defenseshabitat selectionmigration