Wasp Size and Prey Load in Cerceris fumipennis (Hymenoptera, Crabronidae): Implications for Biosurveillance of Pest Buprestidae

The relationship between predator and prey size was studied in the buprestid hunting wasp Cerceris fumipennis Say in eight widely distributed nesting aggregations in North Carolina, USA. Initial work indicated a significant linear relationship between wasp head width and wasp wet weight; thus, head width was used to estimate wasp body mass in subsequent studies. Prey loads of hunting females was studied by measuring the head width of the wasp, then identifying and weighing the prey item brought back to the nest. There was significant variation in wasp size among nesting aggregations; the average estimated wasp body mass in one site was double that in another. Prey weight varied with wasp weight, but larger wasps had a slight tendency to carry proportionally larger prey. Beetles captured by large wasps (≥120 mg) were significantly more variable in weight than those taken by small wasps (<80 mg). All but the smallest wasps could carry more than their own body weight. Prey loads ranged from 4.8⁻150.2% of wasp weight. Evidence suggests that small wasps bring back more of the economically important buprestid genus Agrilus and thus would be most efficient in biosurveillance for pest buprestids.