What effect does social rank have on display rate in Anolis carolinensis? Can individual display patterns predict social status? Deep Shukla, a graduate student at Georgia State University in Walt Wilczynski’s lab, addressed these questions during Tuesday’s poster session at SICB 2015. Green anoles often form dominance hierarchies in conditions with limited resources (such as those in captivity). Deep predicted that competition for these resources might also cause behavioral variation in display use between dominant and subordinate anoles. Using a mirror to induce display behavior and a female to induce courtship behavior, Deep counted the number of pushups performed by size-matched male anoles in isolation. He then housed two males together for 7 days to allow males to establish a dominance hierarchy within the cage. After the weeklong cohabitation, Deep again measured display frequency levels for each male.
In the baseline trials Deep found that the males who later were identified as dominant and subordinate males did not differ in the frequency of aggressive or copulatory displays. After cohabitation, display use frequency declined for both dominant and subordinate lizards overall, but dominant lizards showed higher levels of aggression relative to subordinates. Deep also found that aggressive behavior was correlated with copulatory display before cohabitation; however, this result disappeared after cohabitation. These results suggest that dominance hierarchies in anoles can alter display behavior use based on social rank! This is exciting because it means that dominance hierarchies may be established and maintained in complex ways. Deep is interested in exploring these relationships further by measuring brain metabolic activity and morphology before and after the establishment of dominance hierarchies. Given his preliminary data, it seems likely that there will be interesting differences in the brain that accompany this suite of behavioral changes!
Note: This post was written by Bonnie Kircher, a graduate student studying anole development in Marty Cohn’s lab at the University of Florida.