Predators promote trait diversification in prey

Abstract

Predator-prey interactions have a major influence on species diversification. The performance and fitness of prey species are heavily dependent on their antipredator responses to specific predators. In nature, predators are distributed heterogeneously across different habitats. Because different predators vary in their predation strategies, a change in the top predators can dramatically alter preys’ defensive traits. Larval Leucorrhinia ancestrally came from lakes dominate with predatory fish (fish lakes). However, they shifted their habitats from fish lakes into lakes with only large invertebrate predators (dragonfly lakes) several times. In this thesis, I examined a series of antipredator traits (burst-escape behavior related traits, behaviour, growth rate, ontogenetic pattern and morphological traits) in order to understand how different predation regimes drive prey trait diversification in European Leucorrhinia species. We found a clear diversification pattern in most antipredator traits. However, unique pattern of traits was also found in growth rate related physiological traits. Eventually, we got a full picture of antipredator traits in Leucorrhinia system. These research I have presented is critical for improving our understanding of adaptive trait plasticity and its widespread occurrence across species and community types. Moreover, the facts that the larval stage is restricted in its distribution and that the adults have a high dispersal ability make odonates as an important model bridging ecology and evolution. My results indicate that it might be possible to disentangle the forces behind natural selection (e.g. directional selection, stabilizing selection) by using Leucorrhinia species.