Wing shape is influenced by environmental variability in Polietina orbitalis (Stein) (Diptera: Muscidae)

ABSTRACT

ABSTRACT We measured variation and covariation in wing morphology in six populations of the fly Polietina orbitalis (Stein) (Diptera: Muscidae) to test for geographic morphological structure. Additionally, we examined the role of environmental variables in determining geographic variation in wing shape. We sampled five populations in the state of Paraná, southern Brazil (Colombo, Fênix, Guarapuava, Jundiaí do Sul and Ponta Grossa), and one in Paraguay (Mbaracayú). We choose 15 landmarks to describe the wing shape and size and 19 environmental variables to describe the local environmental conditions. Our results showed that P. orbitalis wing shape, but not size, varies geographically. A canonical variate analysis showed the existence of two clusters of populations based on wing shape. These groups compare populations in which the wing is slender with groups in which the wings are broad. These shape differences were correlated with variation in elevation, precipitation and temperature but were not allometric. Taken together, these results suggest that wing shape differences in P. orbitalis populations are due to a plastic response to local environmental conditions.