Data from: Humidity affects genetic architecture of heat resistance in Drosophila melanogaster

Laboratory experiments on Drosophila have often demonstrated increased
heritability for morphological and life-history traits under environmental
stress. We used parent-offspring comparisons to examine the impact of
humidity levels on the heritability of a physiological trait, resistance
to heat, measured as knockdown time at constant temperature. Drosophila
melanogaster were reared under standard non-stressful conditions and
heat-shocked as adults at extreme high or low humidity. Mean knockdown
time was decreased in the stressful dry environment but there was a
significant sex-by-treatment interaction: at low humidity females were
more heat resistant than males, whereas at high humidity the situation was
reversed. Phenotypic variability of knockdown time was also lower in the
dry environment. The magnitude of genetic correlation between the sexes at
high humidity indicated genetic variation for sexual dimorphism in heat
resistance. Heritability estimates based on one-parent – offspring
regressions tended to be higher under desiccation stress and this could be
explained by decreased environmental variance of heat resistance at low
humidity. There was no indication that the additive genetic variance and
evolvability of heat resistance differed between the environments. The
pattern of heritability estimates suggests that populations of D.
melanogaster may have a greater potential for evolving higher thermal
tolerance under arid conditions.