'Foraging' for a place to lay eggs: A genetic link between foraging behaviour and oviposition preferences

<div><p>Gravid female arthropods in search of egg-laying substrates embark on foraging-like forays: they survey the environment assessing multiple patches, tasting each with their tarsi and proboscis, and then, if interested, they deposit an egg (or eggs). In fruit flies, <i>Drosophila melanogaster</i>, allelic variation in the <i>foraging</i> gene (<i>for</i>) underlies the rover/sitter foraging behaviour polymorphism. Rover flies (<i>for</i>^R) are more active foragers (both within and between food patches) compared to sitters (<i>for</i>^s). In nematodes, <i>Caenorhabditis elegans</i>, a mutation in <i>egl-4</i>, the ortholog of <i>for</i>, leads to aberrations in egg laying. Given this and the notion that females may ‘forage’ for a place to oviposit, we hypothesized that <i>for</i> may underlie egg-laying decisions in the fruit fly. Indeed, when given a choice between patches of low- and high-nutrient availability, rovers lay significantly more eggs on the low-nutrient patches than sitters and also a sitter mutant (<i>for</i>^s2). We confirm the role of <i>for</i> by inducing rover-like oviposition preferences in a sitter fly using the transgenic overexpression of <i>for</i>-mRNA in the nervous system.</p>