Preliminary systematics of the ant-like leaf beetles (Tenebrionoidea: Aderidae) and the evolution of sexual dimorphism

The ant-like leaf beetles (Aderidae) are a relatively small tenebrionoid family consisting of approximately 1,200 species parsed into 45 genera that inhabit all continents except Antarctica. These beetles are intriguing from a natural history perspective as many species inhabit cave systems and some species are social parasites of termites. Though observations of these beetles raise interesting questions regarding insect behavior, chemical ecology, and social insect structure, work on the group has been inhibited by the chaotic nature of the current classification and the absence of a phylogeny for the Aderidae. Additionally, the metafemoral hairs of aderid taxa have traditionally and recurrently been used to define subfamilies, tribes, and subtribes. Unfortunately, reliance on these characters has resulted in further taxonomic confusion as most species are sexually dimorphic, but there are also many species where both sexes possess metafemoral hairs and species where both sexes lack metafemoral hairs. Have sexually dimorphic metafemoral hairs arisen once or multiple times? Has dimorphism evolved through the gain of hairs in males or the loss of hairs in females? To what degree do these sexually dimorphic characters convey phylogenetic signal? A preliminary phylogenetic hypothesis for the Aderidae is presented based on nuclear (ArgK, CAD1) and mitochondrial (CO1, 16S) molecular markers. The monophyly and current relationships of the subfamilies and tribes are assessed. The metafemoral hair characters are mapped onto the preferred phylogeny and evaluated within this phylogenetic framework.