Insect oviposition site selection as a simple system to investigate the ecology and evolution of pathogen avoidance behaviour

Pedro F Vale , Cara Duffy

Pathogen avoidance is a form behavioural immunity and provides the first line of defence from infection. This article discusses insect oviposition as a tractable, mechanistically grounded model for behavioural immunity and sets a concrete research agenda linking individual egg-laying decisions to population level disease dynamics. Because egg laying decisions determine offspring exposure to pathogens and parasitoids, they provide a natural assay of infection avoidance with measurable impacts on fecundity, egg viability, larval survival and future infection outcomes. The sensory basis of pathogen related egg-laying decisions is unusually well mapped in insects such as Drosophila, spanning olfactory detection of microbe and parasitoid derived cues and gustatory detection of bacterial components. We further describe how these decisions are also shaped by ecological trade offs and social information. Egg-laying decisions are also likely heritable, opening routes to selection experiments and inference of eco evolutionary feedbacks. Together, this article outlines how insect oviposition can link cue detection to neural and immune pathways, to individual fitness and, ultimately, to population level transmission and pathogen evolution.