The Curious Case of the Left-Sided Dewlap: Directional Asymmetry In the Curaçao Anole, Anolis lineatus.

We examined asymmetry in the color of the dewlap of Anolis lineatus from Curaçao. We confirmed previous reports that one side of the dewlap appears more yellow in color than the other and, contrary to previous work, demonstrate a directional bias such that the left side is usually the more yellow side. At one site surveyed twice in 3.5 years, the proportion of left- and right-sided males changed significantly. A behavioral experiment failed to find a significant tendency for males to direct the more yellow or more orange side of the dewlap to other individuals while displaying.