The overall goal of our research program is to is to investigate and elucidate the molecular mechanisms underlying how insects communicate and adapt in our changing environment. We focused on a class of compounds called cuticular hydrocarbons (CHCs) which plays dual roles in ecological divergence and mating (Chung et al. 2014, Chung and Carroll 2015). As a member of an Entomology department, we to balance our research between basic research in Drosophila species and applied research in agricultural pests. Here are some of the current projects in our laboratory:
1. CHCs and the evolution of desiccation resistance in Drosophila species: CHCs form a waxy layer on the cuticle of many insects to prevent desiccation due to water loss through the cuticle. Many Drosophila species, such as the desert Drosophila species, D. mojavensis, has evolved high desiccation resistance due to the presence of very long chained CHCs on their cuticle. We aim to elucidate the molecular basis underlying such adaptation using genetics, transgenesis and CRISPR/Cas9 experiments.
2. The evolution of sexually dimorphic CHCs in reproductive isolation: In addition to desiccation resistance, CHCs play roles as pheromones in mate recognition and sexual selection. In many Drosophila species, the evolution of sexually dimorphic CHCs play a role in reproductive isolation between closely related species. In this project, we aim to elucidate the genetic basis of sexual dimorphic CHCs in the melanogaster subgroup and determine if the evolution of these CHCs lead to speciation within this group. We have identified several oenocyte expressed genes which show sexually dimorphic expression patterns and are now characterizing these genes.
3. The evolution of insect metallothioneins: This is a new research direction in our group. Heavy metal is a serious concern in our environment. Many insects have adapted to living in heavy metal polluted environments by evolving detoxification strategies such the rapid expansion of metallothionein (Mtn) gene families. Mtns can bind metal ions and can transport these ions out of the cell, reducing toxicity. However, because of the short sequences and low complexity of these proteins, they are very difficult to identify bioinformatically. To identify Mtns from diverse insect species, we devised an innovative BLAST pipeline to identify all the members of this gene family in insects and determine their evolutionary history. We are now studying the functions of newly identified Mtn genes. (Luo et al. 2020, Proceedings of the Royal Society B)
4. Molecular identification of plant parasitic nematodes: Plant parasitic nematodes are pests in many agricultural crops and the management of these pest requires the proper identification of the species. However, many species are morphologically very similar. We teamed up with the Quintanilla lab to use molecular techniques for the identification of several plant parasitic nematodes in crops including potatoes, carrots, soybean, and sugar beets and blueberries. This research can help grower better manage these plant parasitic nematodes and increase yield. (Cole et al. 2020 Phytopathology, Darling et al. 2021, Plant Disease)