ATTRACTION OF APIS MELLIFERA L. (HYMENOPTERA: APIDAE) TO VOLATILE COMPOUNDS

Anethole and the commercial Trece Japanese beetle lure (1022: 1 1,2-phenylethylproprionate: eugenol: geraniol) exposed in Treci Japanese beetle traps attracted honey bees, Apis rneliifera L. Other floral lures and fatty acids tested did not attract honey bees. The development of food-type lures as attractants for Japanese beetle, Popilla japonica Newman (Ladd and Klein 1982) has stimulated interest in the potential of such compounds as lures for other scarabs. One drawback with the use of Japanese beetle traps is that beneficial insects may also be attracted to the traps. Hamilton et a/. (1970) and Caron and Morse (1972) reported that some chemical lures of Japanese beetle will also attract honey bees, Apis mellifera L. Unfortunately, they did not expose all their lures at the same time and place in a test with a unified experimental design. Tests by Ladd el ol. (1974) showed that honey bees were attracted to anethole and anethole + eugenol(9:l). Ladd and Tew (1983) demonstrated that honey bees were attracted to anethole but not to several other Japanese beetle lures. In testing volatile compounds as attractants for melolonthine beetles, we found that honey bees were attracted to both anethole and a commercial Japanese beetle lure. We exposed lures in Trdce Japanese beetle traps hung 1 m above ground on steel rods 10 m apart at 2 sites near Bundaberg, southeastern Queensland. Lures were exposed for 7 d at each site during OctoberNovember 1989. We tested the following compounds, maker and purity in parentheses: anethole (Fluka, >98%), eugenol (Fluka, >98%), citral (Fluka, 97%), citronellal (Fluka, 85-m%), geraniol (Fluka, >94%), eucalyptus oil (Sheldon Drug Company, purity unspecified), hexanoic acid (BDH, > 98.5%), pentanoic acid (BDH, >98%), and the standard Trece Japanese beetle floral lure (1022:l I, 2-phenylethylproprionate: eugenol: geraniol). All except eucalyptus oil are attractive to various scarabs (Fleming 1969). Lures were evaporated from pieces of sponge placed in the same position as the standard lure and 5 mL of the undiluted lure were added to each sponge each 2-3 d. Standard TrecC lures were not replaced during each test. Ten traps (9 lures and 1 unbaited control) were placed in sugarcane fields and replicated 3 times in a randornised block design at each site. Weekly catches of honey bees were counted in the laboratory, data were analysed using analysis of variance, and means separated using the least significant difference test. Raw data were not normally distributed (P < 0.01, Shapiro-Francia statistic) and were transformed using In(X+ 1) before the analyses (Steel and Torrie 1960). In both tests, anethole attracted significantly (P < 0.01) more honey bees than did the unbaited traps (Table 1). This is consistent with the results of Ladd et al. (1974) and Ladd and Tew (1983) that anethole in Japanese beetle traps attracts honey bees.