The Ecology and Nesting Behavior of the Pompilidae (Hymenoptera) of the Northeastern United States

Wasps of the family Pompilidae occur in a wide variety of situations, but individual species tend to be strongly restricted ecologically. Certain species inhabit rocky stream-beds, others the banks of sluggish streams, and numerous species sandy beaches along streams, lakes, and the ocean. Inland habitats include bare places in gardens and prairies, sand pits, and dunes; a considerable number of species also inhabit open woodlands. The species inhabiting a given situation tend to exploit their environment in different ways, most notably by preying upon different types of spiders or by exhibiting different types of nesting behavior. The more generalized Pompilidae prey upon errant spiders and capture the spider before building a nest. The nest is a simple burrow in the soil with an enlarged terminal cell. The wasp carries the spider by grasping it in the mandibles by the posterior leg-bases and walking backward. Most Pompilini adhere fairly closely to this pattern, but some genera exhibit specialized types of prey-transport, nest in unusual situations, or prey upon web-spinning spiders. Many Pepsini build multicellular nests either in the ground or in series in hollow twigs; most such wasps prepare the nest before capturing the spider. Members of the tribe Auplopodini amputate the spider's legs and walk forward, straddling the prey; most genera of this tribe construct mud cells. The present study considers 45 species of Pompilidae in some detail and concludes with a tabular comparison of certain aspects of the nesting behavior of these species as well as with a host index. Summaries of the ethology of individual genera include pertinent data on extralimital species, but the text otherwise treats only species occurring in the northeastern United States. It is impractical to draw many conclusions regarding the evolution of behavior in these wasps until many more species from other geographic regions, particularly the tropics, have been studied.