Daisy Horr, an undergraduate researcher at Trinity University, discusses how bark anole behavior varies across several different social contexts.
Animals often use diverse behavioral repertoires to adjust to new, unexpected, or changing conditions very quickly. While it may seem like individuals could always use the best behavior for any given situation, we know that instead behaviors are often related within an individual. In other words, an individual’s behaviors are not always independent and may represent an underlying “behavioral syndrome” or correlated set of behavioral responses to related environmental conditions. These behavioral syndromes are also sometimes called “personalities” (though application of this word to animals can be a bit controversial!). So, for instance, an individual that has a “bold” behavioral syndrome might take little time to explore a new habitat or consume a novel food item more quickly, but also be more likely to stay active in the presence of a predator rather than hiding (the safer option!).
While anoles have been the focus of much behavioral research, we still lack an understanding of the diverse behavioral phenotypes, including behavioral syndromes, which are displayed by a variety of anole species. The bark anole, Anolis distichus, is native to Hispaniola but also found in southern Florida where it has been introduced. While small, bark anoles can be quite feisty, and are known for their dramatic display behavior in the presence of male and female conspecifics.
Male bark anoles demonstrate pushup displays prior to engaging in combat.
Taking advantage of the bark anole’s willingness to put on a show, Daisy Horr, an undergraduate student and McNair Scholar in Michele Johnson’s lab at Trinity University, led a group of fellow researchers in assessing whether these anoles show behavioral syndromes. To do this, Daisy and her collaborators measured the degree to which male bark anole behaviors were repeatable across three different contexts: trials with another male present, trials with a female present, and solo trials in which no other anoles were present. They measured variables quantifying movement as well as display behaviors such as pushups and dewlap extensions during these trials. The team also wanted to see whether the measured behavioral traits were linked to morphological and physiological variables.
Daisy and colleagues found no support for the idea that behavior was linked to morphology, including size of the body, head, and dewlap, and mass of the whole body, the liver, and fat pads (structures holding fat as energy reserves), or the hematocrit of the lizards, a metric quantifying how many red cells are present in the blood. Bark anoles did show some level of behavioral consistency, however. Movement behaviors were quite repeatable even between trials with and without conspecifics. Display behaviors, however, including pushups and displays, were repeatable within, but not across contexts. This work suggests that bark anoles have consistent behavioral syndromes in some contexts. Looking forward, research into behavioral syndromes in anoles could offer insights into how behavior may vary with habitat use, ability to invade novel environments, or selection on behavior itself!
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