Attraction ofOryzaephilus surinamensis (L.) andOryzaephilus mercator (Fauvel) (Coleoptera: Cucujidae) to some common volatiles of food.

Responses by adultOryzaephilus surinamensis (L.) andOryzaephilus mercator (Fauvel) to various food volatiles were assessed by means of a two-choice, pitfall olfactometer. The individual experimental stimuli, all potential products of lipid oxidation, had a range of attractive doses of ≤ 1000-fold over the test dose ranges of 0.001-100 gmg, or 0.01-1000 gmg. Of 13 aliphatic C3-C14 aldehydes and benzaldehyde tested forOryzaephilus spp., 10 C3-C10 aliphatic aldehydes and benzaldehyde showed some attractiveness for both species. ForO. mercator, nonanal had the lowest lower threshold for positive response at 0.01 μg. The addition of small amounts of nonanal or of a 1∶1∶1 mixture of hexanal, octanal, and nonanal to small amounts of cucujolide aggregation pheromones enhanced response by mixed-sexO. mercator to the pheromones. Eleven aliphatic C2-C9 free fatty acids showed some attractiveness for bothOryzaephilus spp. Isovaleric acid and valeric acid had the lowest lower thresholds for positive response at 0.1 μg forO. mercator andO. surinamensis, respectively. Four olefinic oat volatiles were found to possess various degrees of attractiveness for bothOryzaephilus spp. The data suggest that food volatiles in this study might be used byOryzaephilus spp. as host-finding kairomones in nature.