Future directions in hydrocarbon research

The research on insect hydrocarbons as semiochemicals has taken a huge leap forward in the past three decades. A crude citation search using the terms “hydrocarbon” and “pheromon” (Thompson ISI) dating from 1965 to 1982, when the first large review of the chemical ecology of hydrocarbons was published (Howard and Blomquist, 1982), revealed 10 citations. A comparable search from 1983 to 2005, the publishing year of the second review by the same authors (Howard and Blomquist, 2005), and using the same terms, revealed 483 citations. Despite the explosion of knowledge regarding all facets of hydrocarbon biology, we are only now beginning to understand their complex role in communication. Here we attempt to indicate some areas of future hydrocarbon research that are expected to enhance our understanding of these structurally simple but biologically important molecules. The ubiquitous occurrence of hydrocarbons and their multifaceted function in insects present the biggest challenge: Hydrocarbons provide an excellent model system for studying the evolution of semiochemicals by co-option, but also present an immense challenge to research. The ubiquitous occurrence of hydrocarbons in the epicuticle and tissues that possess cuticular intima has facilitated their isolation and structure elucidation, but is also one of the major obstacles in deciphering their role in communication. Other confounding factors include the fact that in most cases they occur as highly complex mixtures and, at least for cuticular hydrocarbons, multifaceted functions have been assigned to them.