The hierarchy-threshold model for host-choice in insects predicts positive genetic correlations between use of different hosts, and between host use and the number of eggs carried by females. Life history theory predicts negative covariance between reproductive capacity and lifespan; hence host use and lifespan should be negatively correlated. These predictions were tested in half-sib breeding designs with the cosmopolitan Drosophila busckii. The predictions of the hiecarchy-threshold model were met, supporting previous findings with other Drosophila. Predictions from life-history theory were not met for the population studied. © 1990 The Genetical Society of Great Britain.