Protocol: An absolute egg-to-adult viability assay in Drosophila melanogaster

Measures of organismal fitness must take into account reproductive output and survivorship across life-history stages. In Drosophila melanogaster , a laboratory model system, these traits are often quantified with egg-laying assays and egg-to-adult viability. While several protocols for automated egg counting exist, these methods typically preclude directly analyzing phenotypic distributions in resulting adults. Here, we digitally score eggs from photographs taken under standard laboratory culturing conditions (cornmeal media in polystyrene vials) using a method compatible with scoring surviving adults. This absolute measurement of egg-to-adult viability, that also allows investigation of survivorship biases, was applied to three commonly used laboratory strains.