Attraction of Yellowjackets ( Vespula spp.) to Heptyl Butyrate in Washington State (Hymenoptera: Vespidae)

Abstract

During 2 years of trapping with artificial attractants in the Pullman, Washington, area, 6 species of Vespllla were collect~d. Two species, V. atropilosa (Sladen) and V. pensylvanica (Saussure), were collected in large numbers. V. atropilosa was more strongly attracted to heptyl butyrate than was V. pensylvanica. Most queens and workers collected in attractant traps were V. atropi/osa. Use of artificial attractant traps for controlling yellowjackets is discussed in relation to species composition. The importance of appropriate timing is emphasized and related to the seasonal buildup and decline of worker yellowjacket populations. Davis et al. (]967, 196!\, 1969) and McGovern ct al. (1970) reported attraction of yellowjacket (Ve.l'pllla spp.) workers to synthetic organic compounds. The western yellowjacket, VesplI/a pensy/-vanica (Saussure), was the most abundant species attracted during August and September tests conducted in California and Oregon. Effectiveness of artificial attractants in conjunction with protein baits for yellowjacket control was discussed by Wagner and Reierson (1969). Wagner and Reierson (1971) reported that Ve.l'plI/a queens were attracted during May and June in California, but they did not specify the species involved. Reierson (personal communication) indicated all queens were V. pensy/vanica. Starting in late April 1971, we set out attractant traps in the Pullman, Wash., area to determine which species of Ve.l'pll/a queens were attracted to synthetic organic compounds. Our results showed that queens of V. atropi/o.l'a (Sladen) were strongly attracted during May and June. We follow the taxonomy of Miller (1961) and consider V. atropi/osa a valid species. This paper reports the species of Vespu/a attracted to heptyl butyrate in the Pullman area, and it discusses the importance of timing when attractant traps are used to control yellowjacket queens and workers.