Many Lepidopteran larvae synthesize fatty acid-amides (FAAs) that can elicit the release of volatile compounds from plants during herbivory. These volatiles can attract natural enemies of the feeding caterpillars. Furthermore, plants emit different blends of volatiles in response to herbivory by different caterpillar species. Specialist wasps are able to detect suitable hosts based on these specific volatile cues. Understanding these complex tri-trophic interactions and the role of FAAs in caterpillar metabolism will allow development of more ecologically sound pest control strategies.

Two key enzyme activities associated with synthesis and hydrolysis of FAAs have been identified in caterpillars. The synthase has been localized to gut tissue membranes; the hydrolase is in the lumen of the gut. These enzymes and FAAs are likely to play a role in the metabolism of some caterpillars since they have been retained through evolution despite ultimately attracting predators. To determine the significance of caterpillar FAAs, the synthase and hydrolase enzymes are being examined in several species of Lepidoptera.

In this study, the rates of FAA hydrolysis by enzymes present in the gut of several species of Lepidoptera larvae with different FAA profiles were compared. Results show that the rate of FAA hydrolysis can vary greatly between species, ranging from several minutes to several hours. Furthermore, certain types of FAAs are resistant to breakdown and may hinder the hydrolysis of other FAAs. These differences in hydrolytic rates may affect how much FAA plants are exposed to during herbivory and therefore may change the plant volatile emission profiles.