Pasan Lebunasin Arachchige, undergraduate student

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In the past, morphological characteristics have been the primary means to distinguish species for taxonomical purposes. But morphology alone is insufficient to identify some species. My research project explores this issue using three organisms from the spruce budworm (SBW) cryptic species complex, Choristoneura fumiferana, C. occidentalis, and C. biennis.

These SBW species are economically important forest pests that feed on and defoliate conifers. The goal of my research is to assess whether variation in their morphological characteristics is congruent with variation in their DNA. The genetic data suggests that out of the three species, two main groups exist: C. fumiferana, and a second group that shows partial separation between two subgroups, C. biennis and C. occidentalis. Studying the interactions between morphology and genetic variation will give us a better understanding of species boundaries, as well as genetic mechanisms—such as introgression, convergence, retained ancestral polymorphisms—that underlie the morphological variation between some groups of cryptic species.

I joined the Sperling lab in 2013, the summer right after my first year of undergrad. I have been a member ever since. Initially, my role was to help out around the lab and do small jobs like preparing samples for DNA extractions, then finally doing extractions myself. Little did I know, the skills I acquired from the small jobs and the results of those DNA extractions later became an important part of my current undergraduate research project. This opportunity has been an important part of my university experience, and has been a key factor in initiating the long process of becoming a scientist.