Rattlesnake hunting behavior: a case study across a hybrid zone
Maag, Dylan W.
dmaag3229@sdsu.edu
Shaw, Noelle
Soni, Ashana
Department of Biology
San Diego State University
San Diego, California USA
Nikolakis, Zachary L.
Ivey, Kathleen
Department of Biology
University of Texas at Arlington
Arlington, Texas USA
Schuett, Gordon W.
Department of Biology
Georgia State University
Atlanta, Georgia USA
Chiricahua Desert Museum
Rodeo, New Mexico USA
Castoe, Todd A.
Department of Biology
University of Texas at Arlington
Arlington, Texas USA
Clark, Rulon W.
Department of Biology
San Diego State University
San Diego, California USA
The last several decades of work have demonstrated that hybridization between diverged species is relatively common occurrence. Studying hybrid zones can provide unique insight into the factors that contribute to both pre- and postzygotic isolation and yield critical insights into the processes of introgression and speciation. There is a rich literature characterizing morphology, rates of gene flow, and relative reproductive success at the population level across hybrid zones involving species with strong prezygotic isolating mechanisms. Here, we focus on a system that lacks apparent strong prezygotic mechanisms, which provides the opportunity to examine how postzygotic mechanisms related to the behavior and ecology of individuals may impact hybrids. In this study we focus on a narrow hybrid zone between two rattlesnake species, Crotalus scutulatus and Crotalus viridis, in southwestern New Mexico, and analyze their relationships between ecologically relevant behaviors and the ancestry of individuals. We used a combination of radiotelemetry and field videography to analyze individual snake hunting behaviors across habitat gradients across this hybrid zone. Individuals from all lineages (parentals and hybrids) exhibited similar rates of encounters and successful attacks toward prey (mainly nocturnal mammals). However, in contrast to hybrids and C. viridis, adult C. scutulatus hunted almost exclusively during the night, and they never encountered or struck at potential lizard prey. These findings indicate that C. scutulatus may be more of a small mammal specialist than the other lineages we studied. We discuss the potential implications of these findings in the context of hybrid zone dynamics and postzygotic isolation.