Hybrids between two species are generally less fit than the parental species, and the mechanisms underlying their fitness reductions can manifest through different traits and at different life history stages. For example, hybrids can have physiological, behavioral, or ecological defects, resulting in postzygotic isolation between their parental species. However, mechanisms of postzygotic isolation other than sterility and inviability have remained largely uninvestigated. Isolated studies have found that other postzygotic defects are not only possible but might be widespread. Here, we study a fundamental animal behavior - the ability of individuals to find food - and test the rate at which it breaks down in hybrids. We measured the ability of hybrids from 94 pairs of Drosophila species to find food and show that hybrids are generally less successful than their parental species. We then show that the ability of hybrid offspring to locate food decreases with increasing genetic divergence between the parental species. Our findings quantify the rate that hybrid dysfunction evolves across the diverse radiation of Drosophila and highlight the need for future investigations of the genetic and neurological mechanisms that affect a hybrid's ability to find a suitable substrate on which to feed and breed.

hybrid_food_choiceZip file containing raw data as well as scripts used for the analyses. Perl scripts were used to load the data into a MySQL database, and R scripts were used for the analyses and to generate the paper figures.