Date of Award

Spring 1999

Document Type

Restricted Thesis

Terms of Use

© 1999 Ethan J. Friedman. All rights reserved. Access to this work is restricted to users within the Swarthmore College network and may only be used for non-commercial, educational, and research purposes. Sharing with users outside of the Swarthmore College network is expressly prohibited. For all other uses, including reproduction and distribution, please contact the copyright holder.

Degree Name

Bachelor of Arts



First Advisor

Roger Latham

Second Advisor

Colin Purrington


The grass-dwelling beetle fauna of five Pennsylvania and Maryland serpentine barrens of varying sizes was sampled in effort to assess whether these areas serve as refugia for rare beetle species. A number of serpentine barrens species show an unusual disjunct distribution, with populations in Eastern serpentine barrens and Midwestern prairies, and it was hypothesized that serpentine beetle species would possess a similar distribution. The number of beetle species found in each barrens was compared with the number of serpentine-restricted plant species in the barrens and the barrens size. The distribution of the beetles captured was analyzed using detrended correspondence analysis (DCA) to search for patterns in the distribution. A total of 13 families and 44 species were collected, of which 27 were fully identified to species. Three rare beetle species new to Pennsylvania, Longitarsus arenaceus, Graphops varians, and Cephaloscymnus z. zimmermani were found in serpentine barrens. Of the 27 identified species, three possessed a disjunct distribution between Eastern serpentine barrens and the Midwest. The number of serpentine-restricted plant in each barrens did not exhibit a significant relationship with the number of beetle species in each barrens when examined using correlation analysis. A linear regression comparing barrens size and the number of beetle species captured, however, was positive and marginally significant, suggesting that the size of a barrens is the most important predictor of the number of beetle species present. DCA showed a close relationship between the three rare species new to Pennsylvania and two of the five serpentine barrens sampled, New Texas and Pilot barrens, suggesting that these barrens should receive priority for conservation purposes. Potential future research on serpentine beetle diversity is discussed.