THE HIGHLY AUTAPOMORPHIC ANDROCONIAL CHEMICAL BLENDS OF SYMPATRIC BRAZILIAN SULPHUR BUTTERFLIES (LEPIDOPTERA: PIERIDAE: COLIADINAE)

Resumen

Chemical cues play an important role in the short-range communication of butterflies, remarkably in sexual attraction and mate choice. Differentiated scale patches on the wings of male butterflies, the androconia, are involved in the emission of pheromones. Here we describe the androconial morphology of six sympatric species of Neotropical sulphurs belonging to three genera of the Colias-clade (Lepidoptera: Pieridae), which occur in northeastern Brazil. The chemical composition of secretions was comparatively investigated to determine species-specific trends that might be involved in reproductive isolation and to verify if they yield phylogenetic signal. SEM imaging showed that the androconial patches from all species are differentiated from the non-androconial male wing surface by the higher density of scales, which compared to ordinary scales also exhibit larger windows in the upper lamellae that could facilitate the release of semiochemicals. Gas chromatography – mass spectrometry analyses revealed 68 compounds exclusive to androconia, and specific chemical profiles were evidenced for each butterfly species through multivariate statistics. The majority of androconial compounds were autapomorphic and only four were dominant in more than one species. Apart from the clustering of the two species of Anteos in a single clade, our results revealed low similarity values between the investigated species and a weak correlation between genetic distances and chemical dissimilarities.