March 16, 2021
Rachel Harman presents at Entomology Seminar March 16
Rachel Harman will present "Habitat fragmentation and range margin effects on dispersal and interactions between competitors" at the next Entomology Seminar from 4-5 p.m. Tuesday, March 16, via Zoom. Harman is a new postdoc in the Kim Lab in entomology and recently completed her doctorate with Jim Cronin at Louisiana State University.
Dispersal is a fundamental process that affects local and regional dynamics, including population persistence, range expansion, and interspecific interactions. Changes in these dynamics are of particular interest in anthropogenically modified landscapes as organisms’ behavior often changes in disturbed environments. For my talk, I will outline how fragmentation affects dispersal and the interactions of insects within the local patch and regional landscape. I was able to detect nonlinear, u-shaped density-dependent emigration, which is a rare but ecologically important form. At the patch level, I assessed inner-habitat movement and emigration by Ischnodemus conicus (Van Duzee), a marsh blissid bug. To assess movement at the landscape level, I took a novel approach of studying range expansion with populations selected for dispersal, competition, and fecundity traits in a three-way tradeoff using the flour beetle species Tribolium castaneum (Herbst) and T. confusum (DuVal)). Typically, this tradeoff is assessed by manipulating just one trait; however, I additionally applied concurrent selection pressures of dispersal and competition to better represent an evolving range core and front. Overall, my research evaluates insect movement at multiple scales, from individuals within a patch to communities in a landscape and examines previous research while suggesting improvement for the future.