First European report of social wasps trapped in response to acetic acid, isobutanol, 2-methyl-2-propanol and heptyl butyrate in tests conducted in Hungary

Five species of social wasps were captured in trapping tests in Budapest (Hungary) that evaluated the attractiveness of acetic acid, isobutanol, 2-methyl-2-propanol, and heptyl butyrate. Both Vespula vulgaris (L.) and Vespula germanica (F.), were captured in traps baited with isobutanol, the combination of acetic acid and isobutanol, and the combination of acetic acid and 2-methyl-2propanol. V. germanica did not respond to acetic acid or to heptyl butyrate. V. vulgaris also responded to acetic acid alone, and 2methyl-2-propanol alone, but did not respond to heptyl butyrate. Both V. germanica and V. vulgaris responded more strongly to the combinations of acetic acid with isobutanol and acetic acid with 2-methyl-2-propanol, compared to any of these chemicals tested alone. Small numbers of European hornets, Vespa crabro L. were captured in traps baited with acetic acid with isobutanol, but not with any other lures. Small numbers of Dolichovespula media (Retzius) were captured in traps baited with acetic acid, and with the combination of acetic acid and isobutanol, but not with any other lures. The small numbers of Polistes nimpha (Christ) trapped were not large enough for any statistical analyses. These findings are the first European report of attracting and trapping vespid wasps with these chemicals.