Heritability of water-loss rate in Drosophila melanogaster

Twenty-eight isofemale lines of Drosophila melanogaster newly collected from Brownsville, Texas were used to study the genetic component of water loss rates. Two standard laboratory stocks were used to determine basic water balance features of D. melanogaster. The laboratory stocks show greater loss rates at low humidities than at high ones, but neither age nor strain differences are evident. Crosses within and among the isofemale lines, both from standard cultures and from highly Inbred lines, show that there is a genetic component of water loss rate, which is greater in males than in females. Regressions of offspring on midline parent values gave heritability estimates of a water loss rate of 0.33 for males, and 0.17 for females.