DEVELOPMENT TIME AND PUPATION BEHAVIOR IN THE DROSOPHILA-MELANOGASTERSUBGROUP (DIPTERA, DROSOPHILIDAE)

This study is an in-depth analysis of intersexual, intraspecific, and interspecific variability in larvopupal developmental time, pupation s ite preference, and larval and pupal survival of a number of isofemale lines of the species Drosophila mauritiana, D. melanogaster, D. seche llia, D. simulans, D. teissieri, and D. yakuba. There was no significa nt sex differences in pupation height, but females eclosed significant ly earlier than males in all species. In addition, the suggestion of a strong negative correlation between larval developmental time and pup ation height could not be confirmed in this study. The hypothesis that differences in pupation height provide a basis for niche partitioning between closely related species with overlapping distributions was te sted by three planned orthogonal contrast analyses of variance. First, the two species D. teissieri and D. yakuba, with largely overlapping distribution, were significantly different in pupation height. Second, the two allopatric, nonoverlapping island species D. mauritiana and D . sechellia did not significantly differ in pupation height. However, the absence of a significant difference in the final contrast between the two cosmopolitan species D. melanogaster and D. simulans, which ar e often found together, makes us cautious to accept the hypothesis.