Data from: Navigating infection risk during oviposition and cannibalistic foraging in a holometabolous insect

Deciding where to eat and raise offspring carries important fitness consequences for all animals, especially if foraging, feeding and reproduction increase pathogen exposure. In insects with complete metamorphosis, foraging mainly occurs during the larval stage, while oviposition decisions are made by adult females. Selection for infection avoidance behaviours may therefore be developmentally uncoupled. Using a combination of experimental infections and behavioral choice assays, we tested if Drosophila melanogaster fruit flies avoid infectious environments at distinct developmental stages. When given conspecific fly carcasses as a food source, larvae did not discriminate between carcasses that were clean or infected with the pathogenic Drosophila C Virus (DCV), even though cannibalism was a viable route of DCV transmission. When laying eggs, DCV-infected females did not discriminate between infectious and non-infectious carcasses. Healthy mothers however, laid more eggs near a clean rather than an infectious carcass. Avoidance during oviposition changed over time: after an initial oviposition period, healthy mothers stopped avoiding infectious carcasses. We attribute this to a trade-off between infection risk and reproduction. Laying eggs near potentially infectious carcasses was always preferred to sites containing only fly food. Our findings suggest infection avoidance contributes to how mothers provision their offspring and underline the need to consider infection avoidance behaviors at multiple life-stages.觅食与产卵选址对所有动物的适合度均具有重要影响，尤其当觅食、取食与繁殖过程会增加病原体暴露风险时。在完全变态发育的昆虫中，觅食行为主要发生于幼虫阶段，而产卵决策则由成年雌性个体完成。因此，针对病原体规避行为的选择压力可能在发育层面相互解偶联。本研究结合实验感染与行为选择实验，探究黑腹果蝇（Drosophila melanogaster）是否会在不同发育阶段规避感染环境。当以同种果蝇尸体作为食物源时，幼虫无法区分清洁尸体与感染了致病性果蝇C病毒（DCV）的尸体，尽管同类相食是DCV传播的可行途径之一。产卵过程中，感染DCV的雌性个体同样无法区分感染与未感染的尸体；但健康的雌性成虫会在清洁尸体附近产下更多卵，而非感染尸体附近。产卵阶段的规避行为会随时间发生变化：在初始产卵期过后，健康雌性成虫便不再规避感染尸体。我们将这一现象归因于感染风险与繁殖需求之间的权衡。相较于仅含有果蝇饲料的产卵位点，雌性成虫始终更倾向于在潜在感染的尸体附近产卵。本研究结果表明，病原体规避行为会影响雌性成虫为后代选择产卵位点的策略，同时也强调了需在多个生命阶段考量病原体规避行为的必要性。