Remarkable sexually dimorphic features ofConiceromyia(Diptera: Phoridae): evolution in the light of phylogeny and comparative evidence about their function

Abstract

AbstractConiceromyia is a genus of 100 species of phorid flies mostly distributed in the Neotropical region. The genus is distinguishable based on several male-exclusive features in different parts of the body, many of which are unique among the Phoridae. In addition, many species of Coniceromyia have nearly identical morphology of their male copulatory apparatus (i.e. hypopygium). The co-occurrence of these unusual characteristics suggests an evolutionary correlation between them. To investigate this possible correlation and to understand other aspects of the evolution of these puzzling male-exclusive characters, we performed the first phylogenetic analysis of Coniceromyia, based on morphological and molecular data. Ancestral state reconstructions and comparative analyses then allowed us to infer the evolution of these characters and search for general evolutionary patterns and correlated histories. We demonstrate that these male-exclusive features varied from highly homoplastic to uniquely derived on the phylogenetic history of Coniceromyia. For some characters, we found evidence of a biased evolution favouring gains over losses of the feature, but no male characteristics were significantly correlated with hypopygium morphology. The evolutionary patterns of the male-exclusive features and comparative evidence with other better known groups suggest possible functions for these features related to sexual selection.