Study Sheds Light on Chemicals That Insects Use to Communicate and Survive

Method devised by UC Riverside scientists isolates new chemicals that could be exploited to control pest species

By Iqbal Pittalwala on January 13, 2015

Most insects, such as the Argentine ant seen here, are covered with a thin layer of hydrocarbon molecules as a waterproofing barrier. Photo credit: Mike Lewis, CISR, UC Riverside.

RIVERSIDE, Calif. Most insects are covered with a thin layer of hydrocarbon molecules as a waterproofing barrier. Embedded in this layer are compounds that the insects use as chemical signals for a wide variety of functions such as communicating species and sex. In insects such as ants that live in colonies, they also differentiate the different castes (e.g., workers, queens, and drones).

But isolating these chemicals and determining their absolute configuration and functions has been a challenge because the chemicals occur in complex mixtures which are hard to separate.

Now a team of entomologists and chemists at the University of California, Riverside has devised a straightforward method for purifying these compounds that could result in new green methods of controlling pest species, like ants, by disrupting the organization of their colonies.

The researchers devised a technique that combined known fractionation methods with reverse phase high performance liquid chromatography powerful tools in analysis. Specifically, they used their method to isolate 36 pure hydrocarbon molecules from the complex blends of 20 randomly chosen species in nine insect orders, so that these compounds could be conclusively identified, and the effects of the individual chemicals could be tested.

Jocelyn Millar is a professor of entomology and chemistry at UC Riverside. Photo credit: Millar Lab, UC Riverside.

In so-called social insects that live in large colonies, such as ants and bees, these chemicals have additional functions, explained Jocelyn G. Millar, a professor of entomology and chemistry, whose lab led the research team. The queen in these colonies, for example, uses the chemicals to preventher workers from laying eggs of their own, ensuring that she remains the only reproducing female in the colony.

The efforts of his research team were complicated by the fact that these chemicals can occur in right-handed (R) or left-handed (known as S, from sinistro, the Latin word for left) forms. Moreover, Millar and his colleagues did not know whether some insects produce the R form and others produce the S, or whether they all produced one form.

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Study Sheds Light on Chemicals That Insects Use to Communicate and Survive