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

Pedro F Vale , Cara Duffy

Behavioural avoidance of pathogens and parasites is a ubiquitous first line of defence, yet we lack tractable systems that connect cue detection to fitness consequences, population transmission, and coevolution. We propose insect oviposition as a model that yields general principles for avoidance across taxa. Oviposition decisions fix offspring exposure, they are governed by well‑mapped sensory and neuro‑immune pathways, and present natural trade‑offs with nutrition, competition, and search costs. Synthesising this literature, we advance a predictive framework with several testable hypotheses: (i) avoidance shows nonlinear reaction norms likely yielding stabilising selection across risk-resource mosaics; (ii) opportunity and density‑dependent costs shift optima toward intermediate avoidance and maintain genetic and social‑context dependent polymorphism (G×E and social G×E); (iii) avoidance reduces contact rates and selects on pathogen detectability and virulence when detectability covaries with pathology; and (iv) social information can amplify or override direct cues, creating frequency‑dependent dynamics. By uniting mechanism with eco‑evolutionary theory in a highly tractable system, this synthesis delivers general, testable predictions for behavioural immunity with implications for disease and pest management.