The effect of 1-pentadecene on Tribolium castaneum behaviour: Repellent or attractant?

Abstract

BACKGROUND Movement of the red flour beetle, Tribolium castaneum (Herbst) (Coleoptera: Tenebrionidae), in stored products is mediated by food volatiles and other semiochemicals. RESULTS In two-way olfactometer assays, T. castaneum was more attracted to wheat bran previously infested with conspecifics than to uninfested bran. Chemical analysis showed that 1-pentadecene was present in the headspace of T. castaneum-infested wheat bran, but not detectable in the headspace of uninfested bran. An olfactometer was used to test the effect on T. castaneum behaviour of 1-pentadecene, and of volatiles from wheat bran with and without 1-pentadecene. The lowest concentration of 1-pentadecene exhibited an attractive effect, compared to the control (n-hexane). Slightly higher concentrations showed a neutral effect, while the highest concentrations repelled T. castaneum. Wheat bran with a low 1-pentadecene concentration was more attractive than wheat bran alone, whereas higher concentrations of 1-pentadecene were repellent. CONCLUSION The results provide important information on intraspecific, semiochemical-mediated behaviour in T. castaneum, which could potentially be used to develop new methods to monitor the flour beetles in stored products.