Population genetics of black widows:

an evaluation of genetic variation among widow individuals, populations and species using AFLP genotyping

My name is Ashley Gohr and I am a sophomore, life sciences major at Arizona State University’s west campus.. Although this is my first semester of undergraduate research, my remaining 3 years at ASU will be dedicated to an integrative  study of black widow behavior, population ecology and population genetics.  Under the guidance of both Dr. Johnson and Dr. Geoff Morse, I will be employing amplified fragment length polymorphisms (AFLPs) to quantify genetic variation among individuals, populations and species of widow spiders.  Individual variation (both genetic and behavioral) is largely ignored in the field of behavioral ecology and we are interested in understanding how and why individual animals are different.  Population-level variation will allow us to better understand how spiders adapt to varying ecological conditions.  In particular, in collaboration with the CAP-LTER, we are trying to characterize differences (behavioral, ecological, and genetic) between urban widow populations and desert widow populations.  Urban and desert spiders live very different lives in that urban populations are more densely populated, and as a result of their coexistence with human development, encounter significantly higher abundances of prey and enemies.  We aim to document the genetic variation underlying population differentiation and the phenotypic variation used by populations to thrive in their different habitats.  Finally, the African Brown widow (Latrodectus geometricus) has been introduced to North America and proven itself an exotic, invasive pest.  Collecting from a recent introduction site in Torrance, CA., we will characterize the behavior, ecology and population genetics of this introduced population of brown widows.  We hope this will allow us to understand why brown widows are such a successful invasive species and perhaps suggest ways to control their spread that do not employ large-scale pesticide applications.  I would like to thank the Salt River Project, CAP-LTER and Barrett Honor’s College for their financial support.