Composition of volatiles from fermenting pollen dough and attractiveness to the small hive beetle Aethina tumida, a parasite of the honeybee Apis mellifera

The response of the small hive beetle (SHB), Aethina tumida Murray, to volatiles from a pollen-based diet conditioned by the feeding of 100 adult virgin female or male SHBs (4-8 weeks old) for 1, 3, 7 or 14 days is described and compared to that of the same diet inoculated with the yeast Kodamaea ohmeri (NRRL Y-30722), isolated from the beetle. In a wind tunnel, volatiles from pollen dough conditioned by beetles of either sex for 3 or 7 days lured significantly more beetles into traps than volatiles from unconditioned dough. In contrast, trap captures with volatiles from dough conditioned for 1 and 14 days were weakly attractive. In cage bioassays, when naïve, unfed, virgin, SHBs (3-4 days old) were given a choice between yeast-inoculated pollen dough and non-inoculated dough, the responses were similar to those obtained in the wind tunnel with dough conditioned by SHBs for 3 and 7 days. Chemical analysis revealed high levels of fermentation-related products in volatiles that attracted the beetle.