Studies of Oogenesis in Natural Populations of Drosophilidae. I. Relation of Ovarian Development and Ecological Habitats of the Hawaiian Species

Abstract

The fecundity potential of Drosophila populations endemic to Hawaii has been investigated by analyzing the ovarian development of species in their natural habitats. Species differ in mean number of ovarioles per fly and/or number of mature eggs per ovariole. This diversity is probably an adaptive response of the population to the larval food supply which is determined by the nature, abundance, and nutritional content for larval growth of the oviposition substrates. Three groups of species were recognized on the basis of their fecundity potential and their use of comparable ovipositing substrates: species with a low potential, breeding on flowers (pollen); species with a medium potential, breeding on decaying leaves (bacteria); and species with a large potential, breeding on decaying stems (yeast). Adaptive mechanisms in oviposition behavior (single egg or cluster oviposition) and in the development and function of ovarioles (alternating ovariole development or synchronous ovariole development) which coordinate the reproductive potential of the species with the nutritional content of their breeding substrates are discussed, as is the importance of environmental parameters in determining realized fecundity.