Patterns and processes of genital evolution in Pentatomidae: Pentatominae (Insecta, Hemiptera)

Abstract

High interspecific variability on male genitalia is one of the most widespread phenomenon across animals. In contrast, female genitalia are severally overlooked for many groups, often assumed as invariable in studies of taxonomy, systematics and evolution. The processes responsible for such patterns are still to be fully understood, but several evidences have been pointing sexual selection as a general mechanism. In animals of polyandric mating system, the action of sexual selection seems to be quite stronger, resulting in extremely complex genitalia composed by several components whose functions go beyond sperm transfer. Due to the high functional diversity of the genitalia in polygamous animals, the action of distinct evolutionary mechanisms over different components of one genitalia should be expected (i.e. directional sexual selection, stabilizing selection or neutral evolution). However, virtually all studies of genital evolution are restricted to only one genital feature of each sex, and therefore, the hypothesis of distinct mechanisms acting over different components of one genitalia has not yet been tested. Insects of the subfamily Pentatominae are good models for studies of genital evolution because both males and females possess externally well-developed genitalia. Pentatomins are insects with complex genitalia that are broadly documented and well known from a morphological perspective. On the other hand, the evolutionary patterns and processes associated to such structures are still completely unknown within the group. The project herein aims to reconstruct the evolutionary history of Pentatominae using molecular data in order to test the hypothesis of the action of distinct mechanisms over one genitalia, and also assess the rates of evolution of female and male genitalia within the group. Furthermore, a multiple hypothesis testing will be conducted about the function and mode of operation of the genitalia in Pentatomidae. Such aspect is nearly unexplored in the subfamily, but it is crucial to the development of future hypotheses on the genital evolution of the group. (AU)