Genetic variation for oviposition behavior in Drosophila melanogaster. II. Oviposition preferences and differential survival.

Several behavioral traits connected with oviposition were studied in Drosophila melanogaster strains which ahd been kept on regular and ethanol-supplemented food. All strains preferred food with a low agar content for oviposition, though this tendency was more pronounced in an ethanol-adapted strain. Oviposition on regular and ethanol-supplemented food was tested both under choice and no-choice conditions. Though dependent on the alcohol dehydrogenase genotype adapted strains in general preferred ethanol food, while control strains preferred regular food. There was a strong tendency for oviposition on the vertical sides, when food blocks were offered. This tendency was more pronounced in the ethanol adapted strains. For egg insertion (for which the genetic basis was analyzed in the preceding paper; Kamping and van Delden, 1990), it was shown that inserted eggs laid on ethanol food hatched more often than noninserted eggs. The adaptive significance of the genetic differences in oviposition behavioral traits is discussed.