Evaluating Buprestid Preference and Sampling Efficiency of the Digger Wasp, Cerceris fumipennis, Using Morphometric Predictors

In-ground colonies of the native digger wasp, Cerceris fumipennis Say (Hymenoptera: Crabronidae), were sampled over two years in four New York State counties to characterize prey range, primarily their preying on beetles in the metallic wood-boring family, Buprestidae. These records were also used to evaluate beetle sampling efficiency by comparing collected beetles to historic county records and to identify limitations of wasp-mediated sampling in study areas. Overall, 1,530 beetles representing three families and 44 beetle species were collected from C. fumipennis. Five of these species (Agrilus cuprescens (Ménétriés) (Coleoptera: Buprestidae), A. pensus Horn, Buprestis nutalli Kirby, Chrysobothris scabripennis Gory and Laporte, Dicerca pugionata (Germar)) were new prey records for C. fumipennis. The wasps exhibited a strong preference for larger beetle genera (e.g., Dicerca, Buprestis), which accounted for 68% of beetles caught. Agrilus and Chrysobothris were the next dominant genera, accounting for 16% and 11%, respectively. A 4–19 mm prey size range is proposed, as all beetles collected were within this range despite the availability of prey outside of this range. Cerceris fumipennis caught 43% of the 42 buprestids species present in museum records from the four census counties as well as an additional 23 buprestid species that were not represented in museum records. Of the 22 buprestid species identified in museum collections that were not caught by C. fumipennis in the census counties, only one was within the proposed size range and active during the C. fumipennis flight season (late June through August). Overall, sampling C. fumipennis colonies over two summers at five sites resulted in 32% of the recorded buprestid species in New York State being caught, indicating that monitoring colonies is an efficient and viable means of quantifying buprestid assemblages.