Micro‐geographical scale variation inDrosophila melanogasterlarval olfactory behaviour is associated with host fruit heterogeneity

Abstract

AbstractOrganisms utilize environmental cues to deal with heterogeneous environments. In this sense, behaviours that mediate interactions between organisms and their environment are complex traits, especially sensitive to environmental conditions. In animals, olfaction is a critical sensory system that allows them to acquire chemical information from the environment. The genetic basis and physiological mechanisms of the olfactory system ofDrosophila melanogasterMeigen (Diptera:Drosophilidae) are well known, but the effects of ecological factors on the olfactory system have received less attention. In this study, we analysed the effect of environmental heterogeneity (different host fruits) on variation in larval olfactory behaviour in a natural population ofD. melanogaster. We generated half‐sib lines ofD. melanogasterderived from two nearby fruit plantations,Vitis viniferaL. (Vitaceae) (‘grape’) andPrunus persicaL. (Rosaceae) (‘peach’), and measured, using a simple behavioural assay, larval olfactory response to natural olfactory stimuli. Results indicate that patterns of variation for this trait depend on host fruit plantation where lines were collected. In fact, only lines derived from ‘grape’ showed phenotypic plasticity for larval olfaction, whereas a genotype*environment interaction was detected solely in lines derived from ‘peach’. Therefore, our results demonstrate the existence of genetic differences inD. melanogasterlarval olfactory behaviour at a micro‐geographical scale and also reveal that the trait studied presents a dynamic genetic architecture which is strongly influenced by the environment.