Larval food stress differentially affects flight morphology in male and female speckled woods (Pararge aegeria)

1. Adaptive plasticity in flight morphology can be of great importance for organisms, in order to deal with changing environments. When different demands are imposed to this morphology, different responses to environmental changes can be expected. 2. The aim of this study is to examine whether males and females of Pararge aegeria, which show different flight behaviours, respond differently to larval food stress. 3. In a food-stress experiment, larvae of 35 families were reared on host plants subjected to a drought-stress treatment with three groups: a control group, a low-stress group and a high-stress group. 4. Individuals from stress treatments significantly differed in wing morphology; they had lower wing loadings, and stressed females tended to have more pointed wings than females of the control group. 5. The difference in phenotypic response to food stress between both sexes may indicate that males and females benefit from different changes in morphology. In females, an increase in dispersal capacity may entail fitness benefits, whereas male morphology is mainly shaped by mate-location strategy.