CHANGES IN THE HERITABILITY OF 5 MORPHOLOGICAL TRAITS UNDER COMBINED ENVIRONMENTAL STRESSES IN DROSOPHILA-MELANOGASTER

Heritabilities and evolvabilities for morphological traits were compar ed between two environments in Drosophila melanogaster using parent-of fspring comparisons. One of the environments was favorable. The other stressful environment involved a combination of repeated cold shocks, poor nutrition, and ethanol added to the medium, which markedly decrea sed viability. For wing traits, heritabilities were relatively lower i n the stressful environment, while heritabilities for bristle traits w ere not influenced by conditions. Heritability changes were largely du e to an increase in the environmental variance under stress, whereas l evels of additive genetic variance were relatively constant. Evolvabil ities were similar between environments except for crossvein length.