Composition of volatile compounds in male and female Tenebrio molitor and Leptinotarsa decemlineata before and after the application of insecticides

Abstract

Some insects can be used as food, while others can affect the destruction of crops and the reduction of food reserves. The studies described in this article showed quantitative and qualitative changes in the composition of volatile compounds contained in adult Tenebrio molitor and Leptinotarsa decemlineata insects after applying insecticides. The samples were prepared by SPME and the final determinations were carried out by GC/MS. The volatile compounds that were present only in the insects after the application of insecticides (or in a larger quantities) could be due to the insecticides, as an insect defense response to these insecticides. For example, in adult T. molitor insects, the percentage of alkanes ranged from 38.63 to 59.05% (male), and from 38.89% to 60.20 (female), depending on the insecticide used and the time elapsed since its application. In contrast, in L. decemlineata, the percentage of alkanes ranged from 43.84 to 61.85% (female), and from 42.41 to 60.11% (male). The results of the present study can be useful in understanding the i defense strategies of insects against insecticides.