Attractiveness of infested and uninfested whole wheat grain and coarse wheat meal odors to coleopteran storage insect pests

Abstract

Using a two-way olfactometer, the effects of the whole wheat grains and coarse wheat meal odors on the primary Sitophilus granarius (L.), S. oryzae (L.) and S. zeamais (Motch.) and secondary Tribolium castaneum (Herbst) and T. confusum (Du Val) stored-product pests behavior were examined. Whole wheat grains and coarse wheat meal were used in uninfested and infested form. Whole wheat grains were infested with S. oryzae adults and coarse wheat meal with T. castaneum adults. The odors of infested wheat grains depending on the insect species were 1.9 to 3 times more attractive than the uninfested wheat grains odors, except for the T. castaneum for whome the odors of infested and uninfested grains were equally attractive (p = 0.641). The greatest difference in the attractiveness of the infested and uninfested wheat grains odors was found for T. confusum (3 times longer in the arm with the odors of infested grain), and the smallest for S. granarius (1.9 times). We found that all primary and secondary stored-product pests, depending on the species, were 1.4 - 2.4 times more attracted to the odors of infested compared to the odors of uninfested wheat meal. The greatest difference in the atraction of infested and uninfested coarse wheat meal odors was recorded for the T. confusum, whose adults were 2.4 times longer in the arm with the odors of infested coarse wheat meal than in the arm with odors of uninfested wheat meal, while the smallest difference (1.4 times) was recorded for S. oryzae. The results of this study give a significant contribution to a better understanding of the storage insects behavior, which could be used in the design of new methods of monitoring of their presence in stored products.