Colony distribution and prey diversity of Cerceris fumipennis (Hymenoptera, Crabronidae) in British Columbia

Abstract

Cerceris fumipennis Say, 1837 (Hymenoptera: Crabronidae) is a wasp that provisions its subterranean nests with jewel beetles (Coleoptera: Buprestidae). At 3 newly discovered colonies in British Columbia (BC), C. fumipennis prey were collected by excavating the subterranean nests, using sweep nets to capture paralyzed prey in the grasp of a female returning to her nest, or collecting prey discarded at the nest entrance. In total, 9 species were collected: Acmaeodera idahoensis Barr, Agrilus crataegi Frost, Agrilus granulatus populi Fisher, Anthaxia (Haplanthaxia) caseyi caseyi Obenberger, Chrysobothris laricis Van Dyke, Chrysobothris leechi Barr, Phaenops drummondi (Kirby), Phaenops gentilis (LeConte) and Phaenops intrusa (Horn). Anthaxia caseyi caseyi was the smallest beetle (4.2 mm) while C. leechi was the largest (12.0 mm). The average size of all buprestid prey taken by females from all 3 colonies was 8.8 mm. These represent the first prey records for C. fumipennis in BC and with the exception of P. drummondi are new prey records for this wasp. A single Harpalus affinis (Schrank) (Coleoptera: Carabidae) was discovered within a brood cell containing Acmaeodera spp. elytra, but it is unclear if this beetle was placed in the cell by a female wasp.