Seasonal dynamics and overwintering strategy of the tachinid fly (Diptera: Tachinidae), Ormia ochracea (Bigot) in southern California

We present the first data on the seasonal abundance of an acoustically orienting parasitoid fly, Ormia ochracea (Bigot), in southern California. Peak population abundance of the parasitoid lags peak population abundance of its primary local host species the field cricket Gryllus lineaticeps Stål, by about six weeks. We also examined pupal diapause as a potential overwintering mechanism. Taken together our results suggest (1) that O. ochracea lacks a highly effective pupal diapause, (2) that spring adult field cricket species are safe from the fly, and (3) that most of the late fall flies die without reproducing.