Genomics of speciation, hybridization, and conservation

What are the first genes to change during the formation of new species? How do novel mating signals and behavior evolve? We seek to understand the genetic architecture of traits that create reproductive isolation among populations. We want to know how male and female preferences co-evolve and how multiple barrier traits become coupled together within the genome, possibly within rearrangements. Ongoing work uses the European corn borer moth (Ostrinia nubilalis). Populations of this sweet corn pest can vary in mating pheromone, male pheromone preference, and the seasonal timing of mating. Some of these traits are associated with a large rearrangement on the sex chromosome.

Our research also focuses on factors that determine hybridization rates among species and the maintenance or loss genetic diversity in threatened or declining species. Hybridization is a double-edged sword: beneficial for genetic diversity but it can lead to loss of species-species traits through genetic swamping. Ongoing conservation genetics projects include studying the genetic diversity and documenting extant subspecies of the Frosted Elfin butterfly, Callophrys irus. We are studying the hybridization patterns among North American elfin butterflies (subgenus Incisalia) more broadly, focusing on Eastern pine (C. niphon) and brown elfin (C. augustinus).

Temperature effects on reproduction and genetic change in warming climates

Plasticity and learning also play an important role in speciation process. If mating traits or preferences depend on the environment, shifts in the environment could weaken reproductive isolation and increase hybridization. We seek to quantify the effect of the environment on reproduction and mating behavior to predict how future environmental changes may influence overall biodiversity. We are studying life-stage specific effects of elevated temperature on reproduction using Ostrinia nubilalis as a model for other Lepidoptera. We are exploring the mechanisms associated with adaptive and maladaptive plasticity in reproduction using differences in gene expression and DNA methylation. Other collaborative projects look at genetic changes associated with warming climates (adaptation to temperature, increased hybridization) in both invertebrates and vertebrates.

Other past research topics:

Cascade reinforcement– contact between species leading to further changes in mating traits
Chromosomal rearrangements in speciation
Mate choice, predation, and hybridization