Anole

ddddAnolis Carolinensis serves as a well study example of anoles. It has only two morphotypes, green and brown. This species inhabits warmer clines in North America. The choice of morphotype is important for a few biological functions.

Thermoregulation:

In order to main an optimal performance temperature, anoles will change color in order to absorb or reflect light. If the temperatures are high, the anole will change to a bright green color and the opposite will occur at low temperatures (Fig. 1). Different morphotypes are found at different areas in the habitat. This is because different wavelengths of light exist depending on whether the anole is exposed to direct or shaded light (Macedonia 2001). The great advantage is that the anole can expediate basking in order to reach optimal performance temperature even in reduced light simply by changing its color to a dark brown (Macedonia 2001; Walton and Bennett 1993)

A. carolinensis uses the hormonal mechanisms mentioned in Color Changing Mechanisms in order to induce color change. The pituitary gland is stimulated by light entering from either the eyes or via photoreceptors on the skin.

Fig.1 Adapted from Taylor and Hadley 1969. Reflectance is increased in warmer temperatures, while the opposite is true for colder temperatures. MSH, added after 60 minutes, also reduces reflecatance as the melanophores move to cover iridophores.

There is some evidence that suggests that A. carolinensis will change body color depending on mood or stress level. A darked skin color suggests lower levels of androgen, which seems to correlated with successful courtship (Greenberg 1990). However, there does not seem to be much conclusive data about body coloration and communication in A. carolinensis. There is much more literature concerning the use of the dewlap, which is not covered here.

A. carolinensis do change skin color depending on the background and habitat (Hadley 1969): light green on light green background and dark brown on dark brown background. Although camouflage is definitely a useful tool, it seems that crypsis is not the main purpose for color change in this species (Taylor and Hadley 1969).