Sexual dimorphism is common in animals and derives from two mechanisms: sexual selection and sexual niche divergence. These mechanisms may work together as determinants of wing shape in pigmented wings of Odonata. On the one hand, sexual selection by females tends to enlarge the wing areas of males that host pigments; on the other hand, sex-specific flight behaviours, due to differential niche selection, may promote sexual dimorphism. Both sexes of Sympetrum pedemontanum have ornamented wings with bands, but their function is poorly understood. Therefore, we studied shape and size of wings and wing bands of S. pedemontanum using geometric morphometrics to quantify the extent of sexual dimorphism. We also investigated whether sexual dimorphism in wing shape derives from the effect of sexual selection on wing ornamentation or from sexual niche separation. We found sexual dimorphism in wing shape and in the shapes of the bands, but the absence and misdirection of sexual size dimorphism and wing shape dimorphism of bands do not support the hypothesis that wings and wing bands in S. pedemontanum are subjected to sexual selection. Instead, the pattern of sexual dimorphism in wing shape seems more likely to be caused by sex-specific flight requirements.

Sexual dimorphism in wings and wing bands of Sympetrum pedemontanum (Müller in Allioni 1776)

GALLESI, MARCO MATTEO;SACCHI, ROBERTO
2015-01-01

Abstract

Sexual dimorphism is common in animals and derives from two mechanisms: sexual selection and sexual niche divergence. These mechanisms may work together as determinants of wing shape in pigmented wings of Odonata. On the one hand, sexual selection by females tends to enlarge the wing areas of males that host pigments; on the other hand, sex-specific flight behaviours, due to differential niche selection, may promote sexual dimorphism. Both sexes of Sympetrum pedemontanum have ornamented wings with bands, but their function is poorly understood. Therefore, we studied shape and size of wings and wing bands of S. pedemontanum using geometric morphometrics to quantify the extent of sexual dimorphism. We also investigated whether sexual dimorphism in wing shape derives from the effect of sexual selection on wing ornamentation or from sexual niche separation. We found sexual dimorphism in wing shape and in the shapes of the bands, but the absence and misdirection of sexual size dimorphism and wing shape dimorphism of bands do not support the hypothesis that wings and wing bands in S. pedemontanum are subjected to sexual selection. Instead, the pattern of sexual dimorphism in wing shape seems more likely to be caused by sex-specific flight requirements.
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11571/1101340
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