ABS 2022
Convergent evolution in behavior and physiology in Anolis lizards
Michele A. Johnson. Trinity University, San Antonio, Texas, United States

Most animal behaviors require movement, and movements occur when signals from the brain reach the muscles that facilitate the movement. While motivation to perform a behavior is necessary, motivation and its underlying neural mechanisms are generally not sufficient to produce a behavior; the physiological ability to produce a movement is also required. Variation in behaviors may thus be due to differences in the brain, in physiological traits of peripheral tissues, or (likely) both. I will describe a series of studies exploring how variation in muscular morphology and neuroendocrine traits are associated with variation in social behavior, using lizards in the diverse and speciose genus Anolis. We find that muscle fiber size, number, and type; androgen receptor expression in muscle fibers; and morphology of the neuromuscular junction are associated with the evolution of different behavioral traits in anole lizards. Combined with previous studies of brain and hormonal traits in anoles, these results suggest that the production and evolution of social behavior requires a complex interplay of mechanisms, resulting in a variety of potential targets for selection on behavior.