David L. Clark, Ph.D.
Directed Student Presentations and Achievements
Ms. Anna Springsteen, Comparison of Reflectance Patterns Between Flower-Dwelling and Ground-Dwelling Crab Spiders
Abstract: Crab spiders (Thomisidae), are sit-and-wait predators and can be found in a variety of habitats, including flowers and leaf litter. The objectives of this study were to compare reflectance spectra of a brightly colored, flower-dwelling crab spider (Misumena vatia) to the reflectance spectra of a brown, ground-dwelling crab spider (Xysticus elegans). Reflectance spectra were used to determine how well each blended with their respective substrate and light environments. Reflectance spectra of spider body parts and vegetation structures were gathered in the lab using a 400 um reflectance probe and full spectrum deuterium light source. Results suggest that M. vatia match the spectral properties of the white and yellow flowers they were found on. The ground-dwelling spider, X. elegans, did not match flowers, but did match leaf litter and bark. Interestingly, X. elegans was often found on flowers in field, suggesting that it might be quite conspicuous. However, closer inspection of reflectance spectra of X. elegans body parts suggests they may be cryptic on flower backgrounds in the spectral range that corresponds to insect visual systems.