Life-history evolution in hymenopteran parasitoids : the roles of host and climate

Abstract

In this thesis I studied the relationships between parasitoids, hosts and climate from an evolutionary point of view by using hymenopteran parasitoids as a model system. A comparative approach was used to study the variation in life-history traits of species or populations from different habitats. I showed that closely related species manipulate their host behaviour differently and allocate their essential resources to different life-history traits during development. Metabolic rate and energy reserves varied strongly between species. At the population level, energy reserves were found differ substantially between different climate zones. A molecular study revealed clear genetic divergence of these populations, which partially reflected the pattern in life-history variation. To conclude, I suggest that life-history traits of parasitoids are subject to natural selection pressures from both host and cli mate. Resource allocation and host manipulation in parasitoids is species specific and highly diverged among populations to fit habitat requirements.</p