Olfactory response to beetle-produced volatiles and host-food attractants by Oryzaephilus surinamensis and O. mercator

A two-choice, pitfall olfactometer which utilizes a petri plate with suspended glass vials was employed to test the response of Oryzaephilus surinamensis (L.) and O. mercator (Fauvel) to various volatile stimuli. Male and female beetles of both species were attracted to pentane extracts of Porapak Q trapped volatiles from beetles, frass, rolled oats, and brewer's yeast over a wide range of stimulus concentrations. For both species, male and female frass contained attractive volatiles in addition to those from unused growth medium. This result and the attractiveness of volatiles from beetles suggest that both sexes produce an aggregation pheromone. Additionally, interspecific attraction to beetle and frass volatiles was demonstrated.