Above: Faith Deckard presenting her research on how muscle physiology may explain variation in social behavior among Caribbean anoles.
Marathon runners and elite sprinters, like Usain Bolt, have dramatic differences in their muscle physiology that allow them to specialize in their respective track-and-field events. Whereas sprinters have lots of muscle fibers that produce high force but fatigue quickly, marathon runners have lots of muscle fibers that produce less force but allow much longer activity because of their reliance on aerobic respiration. Might this be true for our beloved Caribbean anoles, too? Faith Deckard of Michele Johnson’s lab at Trinity University tried to answer that very question. She studied six species of anoles in the Dominican Republic to test whether anoles that have higher rates of dewlap extension and extend their dewlap for a longer duration have dewlap muscles with a higher proportion of slow-twitch muscle fibers that can be used for endurance. Surprisingly there was no significant correlation between the two behavioral traits and the proportion of slow-twitch fibers! However, this scrutinizing attendee feels pretty strongly that there is a relationship that is just yet to be teased apart statistically. The raw data Faith presented looked very convincing to me, so we’ll see what the future holds for this question. Faith’s results are a very interesting clue to the still-elusive mechanisms that underlie anole behavioral diversity.