Effect of Selection on Oviposition Site Preference in Drosophila melanogaster

A divergent selection program for gregarious oviposition behaviour was carried out for 112 generations on cage population of D. melanogaster. Gregarious oviposition was measured using five different indices: number of occupied tubes, percentage of eggs in the preferred tube, mean variance ratio, Charlier coefficient of disturbance and k parameter of the negative binomial distribution. All these statistics showed similar tendencies, but k seemed to be the most sensitive indicator of intensity of aggregation. The high aggregation line showed a rapid initial response but little change later. In contrast, the low aggregation line showed a steady but slow response to selection. The realized heritability for the low line in generations 67-73 was 0�11 � 0�04.