Variation in Cell Number in a Population ofBembix Americana(Hymenoptera: Sphecidae)

摘要

This paper reports the results of observations made during thesummers of 1971 and 1972 on a small group ofBembix americanaFabricius nesting in a vacant lot in Seattle, Washington. This population was judged to be intermediate tocomataParker andspinolaeLepeletier at the subspecific level (H. E. Evans, pers. comm.).Probably no North American digger wasp has been more thoroughlystudied thanB. americana(Evans 1957, 1966; Evans andMatthews 1968). However there has only been one report of this.species making nests with more than a single call (Parker 1925).Evans (1966) notes the uniqueness of this account and the difficultyof accurately digging out nests in dense colonies. Nevertheless inthe course of my work I discovered that some of the wasps in Seattlewere making multi-celled nests. The evidence for this is presentedhere as well as data on the nest building behavior of marked femalesover a period of time.