The investigators will study the chemical mechanisms involved in the interactions between insects from the southern cone region and organisms in their environment. Their study will include the characterization of the chemical structure and biological function of substances that insects use for defense against predators, communication with conspecifics, protection of progeny and location of food. Structure elucidation will be attained by modern chromatographic (GC, HPLC) and spectroscopic (NMR, MS, IR) techniques. Biological functions will be studied by electrophysiological techniques (EAG) and field and laboratory bioassays, including predation tests for defensive substances and wind tunnel studies for volatile semiochemicals. The study will focus on species likely to produce new natural products of pharmacological value, as well as on certain local pests.