Prey requirements and immature development of the ground dwelling wasp Cerceris fumipennis

Emerald ash borer (EAB: Agrilus planipennis) is an invasive beetle from Asia and is currently found in 22 states in the US.  EAB has caused the loss of hundreds of millions of ash trees and cost municipalities and industry tens of millions of dollars. Several state and federal projects are utilizing the ground dwelling, predatory wasp Cerceris fumipennis as a biosurveillance tool for monitoring EAB. The use of C. fumipennis for biosurveillance is currently limited to areas where the wasp is naturally occurring.  The development of C. fumipennis mobile colonies would allow the wasp to be more widely utilized.  A poor understanding of the wasp’s growth and phenology hampers the development of mobile colonies.  This study is aimed at understanding the in-ground phenology and prey requirements of immature wasps.  During the 2012–2014 summer field seasons nests were excavated at four different locations in central Maine.  The contents of each nest were assessed relative to prey contents, wasp instar and weight, and nest structure.  We found overlapping life stages within individual nests indicating that the wasps are completely provisioning a cell before starting on the next cell.  Nutritional needs varied by site but a relationship was found between the estimated weight of provisioned beetles and the resulting size of pupa.  Prey fidelity and prey species composition is discussed.  This research will provide the basics for moving forward in the development of mobile colonies, which could significantly increase the use of C. fumipennis as a tool to locate EAB.