Hi!

Modern insecticides target nicotinic acetylcholine receptors (nAChRs) found in the neurons of all animals. Because of the evolutionary differences between mammals and insects, insecticides are believed to be safe for humans and other animals. They are still, however, generalist neurotoxins that target all insect species.
nAChRs are complex structures. Each receptor is built out of five protein subunits, but insect genomes usually encode for 10-15 subunits. Functional receptors, therefore, can be composed out of various combinations of nAChR subunits, acquiring different functions and properties, including affinity to insecticides.
If the usage of the main target receptor varies between species, then we have a basis to believe that their reactions to insecticides will also be different. Therefore, we cannot extrapolate the results of insecticide exposure from one species to another.
We showed that the usage of nAChR subunits varies between two species of bees, the honey bee and the bumble bee, between their body parts, castes, and developmental stages. Such findings shed a new light on the molecular processes that guide the reactions to commonly used insecticides.

The current insecticide safety assessment process has three main flaws:
1. Testing is limited to mesaurements of survival of individual insects. However, intoxication by insecticides can significantly reduce an insect's ability to pollinate, reproduce, and survive in the wild, even if the insect is still alive.
2. Testing uses high doses of insecticides over short periods of time, which does not accurately reflect the long-term, chronic exposure to small doses of insecticides that often occurs in agricultural landscapes.
3. Testing only focuses on the honey bee (Apis mellifera) or a few other species, and toxicity measurements are then extrapolated to thousands of other wild pollinators. This ignores the complex differences in life histories and physiologies among pollinating insects.

In my research, I use high-resolution molecular approaches to understand how these flaws limit our understanding of the negative effects of insecticides. I measure gene expression levels in key tissues, such as the brain or muscles, after exposing insects to different doses of insecticides. I also experiment on various species of insects that are frequently omitted in safety assessments but are important pollinators of many plants, including solitary bees, flies, and butterflies.
Transcriptomic and genomic approaches allow me to uncover the molecular mechanisms behind the detoxification of insecticides and their adverse effects in different insect species, and to directly compare them, which is not possible using more traditional toxicology assays.