Phenotypic plasticity of wings in selection lines of Drosophila melanogaster

Abstract

Plasticity in wing characters was investigated in lines selected for long and short wing length and for long and short thorax length in Drosophila melanogaster. Selection lines were reared at 20°C and at 25°C. All lines were raised across a temperature range from 17.5°C to 27.5°C after several generations of directional selection. We tested whether correlated responses in wing cell size and cell number and in plasticity occurred as a result of selection on wing size or thorax size. A difference in plasticity in the lines was observed at different selection temperatures. Selection at 25°C resulted only in a change in mean values, whereas selection at 20°C led to some correlated responses in plasticity. Different results might have been obtained if more replicates of the selection lines had been started from the same population. The results show that mean size at a temperature and plasticity across temperatures are at least partly determined by different genes.