The joint effect of temperature and host species induce complex genotype‐by‐environment interactions in the larval parasitoid of <i>Drosophila</i> , <i>Leptopilina heterotoma</i> (Hymenoptera: Figitidae)

Abstract

Phenotypic plasticity and genotype‐by‐environment interactions are usually studied by testing environmental factors separately. However, several environmental factors may vary simultaneously across the geographic range of a species, and thus interact to drive phenotypic and genotypic evolution. Here, we address the question of the interaction between two environmental factors in the case of a koinobiont parasitoid of Drosophila , Leptopilina heterotoma (Hymenoptera: Figitidae). Using two allopatric parasitoid lines, we analysed the joint effect of developmental temperature and host species on two major fitness components (pre‐imaginal survival and fecundity) of emerged parasitoids. Our results indicate that both environmental factors strongly interact to shape the parasitoid phenotype. Moreover, complex genotype‐by‐environment interactions appeared that can even invert the relative fitness of the two parasitoid lines.