Chemical Ecology of Insects

If the chemical analysis of plants is the bread and butter of our research group, then the analysis of insect metabolites is the icing on this demanding cake. Plants in general are better chemists than humans, but insects may further complicate the tasks of a phytochemist by modifying the plant metabolites. These processes may be related to detoxification or sequestration. Insects may use the modified metabolites for their own defense against their predators, i.e. the sequestered new metabolites should be then more efficient toxins than the original plant-derived molecules.

The above processes may be species or genus specific, since different insect lineages are found to metabolize compounds of same host plants differently. This way accurate chemical analysis of the formed metabolites may reveal the defensive armory of individual species. This in turn enables us to understand the complex tritrophic interactions of plants, herbivores and their predators. It is not unexpected that harmful plant compounds can be modified in insects, and the harmful compounds are turned into useful ones. But do we understand these processes so that we can claim that the shift from harmful to useful has taken place?

To understand in detail the metabolism of plant compounds has been crucial for us at the Natural Chemistry Research Group. We have learned a lot by using many species of insect herbivores as metabolic models, both in vivo and in vitro. This way we have reached a level where we can claim to understand polyphenol metabolism in insects way better than what is generally known of polyphenol metabolism e.g. in ruminants or in the case of certain compounds even in humans. In a way this is highly surprising, but now we can use our expertise gained with insects to understand polyphenol metabolism in larger organisms, be they e.g. mammals such as ruminants, koalas or primates.