Lachance studies the evolution, biogeography, biodiversity, and systematics of ascomycetous yeasts. The objectives are to document yeast biodiversity in natural habitats at the interface of insects and plants, the process of species formation in nature, and the underlying causes of the global distribution of yeasts. The habitats include floricolous insects, particularly Coleoptera, leaf-eating caterpillars, and tree exudates and the various invertebrates that inhabit them.
One current focus of our laboratory is a group of large-spored Metschnikowia species associated with nitidulid beetles that visit flowers of Convolvulacae and other plants that produce short-lived flowers. The biogeography of these yeasts, their mechanisms of reproductive isolation, and the reconstruction of speciation events are being examined in populations whose distribution ranges across the New World and the Australian-Pacific region. Another focus is the biodiversity of ascomycetous yeasts in the Neotropics. We make extensive use of polymorphic DNA loci to study the genetic structure of yeast populations.
A recent area of interest is the nature of the interaction between yeasts, nematodes, and insects.