Local adaptation of developmental time and starvation resistance in eight Drosophila species of the Philippines

Abstract

The ecological trade-off between developmental time and starvation resistance, acting in a heterogeneous environment, can promote the coexistence of competing species. Heterogeneity results from variation in the vegetation that influences both abiotic (e.g. temperature, humidity) and biotic (e.g. fruit availability during the year) aspects of the environment. In this study, we investigated whether differences between collection sites have led to local differentiation of the two life-history traits underlying the coexistence model: developmental time and starvation resistance. Drosophila were collected from four collection sites, ranging from grassland to secondary forest, along a transect of 15 km. The microclimatic and vegetation differences among these collection sites were considerable. For developmental time, different species showed similar genetic responses to the (habitat) differences between the different collection sites. The shortest developmental times were found in the secondary forest populations and the agricultural area populations, the longest in the grassland populations, and the forest edge populations were intermediate. However, there was no correlation between the habitat ranking based on disturbance and canopy cover, and the ranking of the developmental times. Furthermore, the data did not confirm the generality of the positive correlation between developmental time and starvation underlying the coexistence model. © 2006 The Linnean Society of London, Biological Journal of the Linnean Society, 2006, 87, 115–125.