Evolution of nesting behavior in Ageniellini spider wasps (Hymenoptera: Pompilidae)

Ageniellini (Pompilidae: Pepsinae) is a cosmopolitan tribe of spider wasps notable for their unusual, specialized behaviors associated with prey capture and nesting. Females amputate the legs of their spider hosts, and some species build mud nests communally. Despite their intriguing biology, challenges with taxonomy have hindered the understanding behavioral evolution in this group. Morphology in the tribe is very uniform and genera are often incorrectly identified. Here, we reconstruct the phylogeny of Ageniellini from molecular data, and use the phylogeny to map hunting and nest-construction behavior. We sequenced three nuclear markers for 33 taxa, and coded five behavioral traits (prey transport, amputation, nest-construction, and communalism), which were mapped onto the tree using Bayesian and maximum-likelihood approaches. Preliminary results contradict previous hypotheses concerning evolutionary sequences in nesting behavior. Our analyses support conserved origin for mud nesting, which seems to be associated with communal behavior and modified morphological features. Amputation of all or some legs of prey apparently had multiple origins in the tribe, while cleptoparasitism had a single origin in the members of Poecilagenia. Communal nests are possibly the first step towards sociality, and a reconstruction of the evolutionary path to communal nesting will contribute to an understanding of steps leading to parasociality in Pompilidae in particular, and eusociality in Hymenoptera in general.