Genetic variation for oviposition behavior in Drosophila melanogaster. I. Quantitative genetic analysis of insertion behavior.

The genetic basis of egg insertion behavior was analyzed in two Drosophila melanogaster strains (N and E strain), which were homozygous for the Slow allele of the alcohol dehydrogenase locus. The E strain had been selected for increased tolerance to ethanol. This study originated from the observation that nearly all of the eggs laid by females of the E strain were inserted, while in the control strain (N strain) which was kept on regular food, considerable variation for egg insertion occurred. Crosses between the E and the N strains were made, and quantitative genetic tests were performed. It was shown that the inheritance of egg insertion is polygenic, some of the genes are probably sex linked, and in-laying is partly dominant over on-laying. The heritability of the trait, derived from mother-daughter regression analysis, was .59 +/- .18. The repeatability was high. Bidirectional selection in the E strain was unsuccessful, but an asymmetrical response to selection was obtained in the N strain and in lines derived from crosses between the N and the E strains. Selection for in-laying was more successful than for on-laying. The realized heritability in the former lines was .35 +/- .10.