Predator related oviposition site selection of aquatic beetles(Hydroporus spp.) and effects on offspring life-history

摘要

Theory predicts that natural selection should favour females that are able to correctly assess the risk of predation and then use that information to avoid high-risk oviposition sites to reduce the risk of offspring predation. Despite the potential significance of such behaviour on individual fitness, population dynamics and community structure, relatively few studies of oviposition behaviour connected to the risk of predation have been carried out. However, some recent studies suggest that oviposition site selection in response to risk of predation may be a common phenomenon, at least among amphibians and mosquitoes. A vast majority of previous studies have, however, neglected to investigate how the offspring are affected, in terms of fitness related parameters, by the maternal oviposition site choice. In an outdoor artificial pond experiment the oviposition site selection of female aquatic beetles (Hydroporus spp.) was tested in relation to the presence or absence of a predatory fish (Perca fluviatilis). In addition, the authors monitored how the oviposition site selection affected the behaviour, growth and food resource of the progeny. It is shown that free-flying females of the aquatic beetles Hydroporus incognitus and H. nigrita prefer to oviposit in waters without fish compared with waters with fish. Larval activity of Hydroporus spp. was unaffected by fish presence. These results indicate that beetle larvae from females that do lay eggs in waters with fish show increased growth compared with larvae in waters without fish. This difference in growth is explained by a higher per-capita food supply in the presence of a fish predator. This finding may have important implications for the understanding of how the variance of oviposition site selection in a population is sustained