The beetle-hunting habits of ground nesting wasps in the genus Cerceris Latreille have been recently exploited as a survey technique for exotic and native Buprestidae, particularly Agrilus planipennis Fairmaire (the emerald ash-borer). While such methods have been developed for the wide-ranging eastern Cerceris fumipennis Say, the survey potential of western buprestid-hunting Cerceris spp. has not been explored. Cerceris californica Cresson is the most well-studied of the western buprestid feeders, and the only one known to occur in Washington state. Here we report the results of surveys conducted in Washington in 2012–2013 for C. californica colonies, and numbers of buprestid beetles collected from monitored colonies. Eight C. californica colonies were found through visual search of 228 baseball fields and sandy clearings, but only four were large enough to monitor. Fifty-four beetles were recovered from the four colonies, comprising five native species. Four of these are new prey records for C. californica, and one (Chrysobothris quadriimpressa Gory & Laporte) is newly recorded from Washington. Cerceris californica colonies do not appear to be large or common enough in Washington to be a significant exotic buprestid survey strategy. However, even the limited monitoring resulted in more buprestid captures than nearby purple sticky traps, and monitoring C. californica nests may be a locally useful supplement for general buprestid surveys.
