What drives the color change in green anoles?

Methods

Summary

Prior to testing, after the 3 day acclimating period, the anole will be observed from 8:00 am to 10:00 am, to get baseline data on the frequency of color change. This will be the control group.

To test increased stress levels, the anoles have to be purposefully agitated. In order to agitate them, a small red disk will be attached to a dowel rod, and placed into the middle right side of the terrarium about 8 cm from the bottom. The screen cover will be removed, and a camera slider will be sitting over the top of the cage and the end of the dowel rod will be attached to the camera slider. This ensures that the level and distance the shield is moving each time is constant. The disk will be moved using a string so the terrarium can be kept covered, thus human contact is non existent. The disk will then be pulled to the middle left side of the terrarium, in 5 seconds, pulled back in 5 seconds, and that will be repeated 3 times. Once it has been pushed forward and back 3 times, the camera slider will be pushed to the far left side of the cage (flush with the wall) so that, again, human contact is non existent during the observation period. The anole will continue to be recorded for the following 10 minutes. Any color change that occurs within the red disk moving and the following 10 minutes will be documented as stress-induced. After the 10 minute observation period, the camera slider with the red dish and dowel rod will be removed from the terrarium.

To test the effect of light levels and temperature, there will be 3 scenarios that will be tested. The first one is the ceramic heat emitter off but the light on. The next scenario is the ceramic heat emitter off and the light off. The final scenario is the ceramic heat emitter on and the light off. This is testing to see whether anoles change color to thermoregulate. Because the light is a UVB light, when it is on, it will not emit much heat, so the anole would not have a place to bask when the ceramic heat emitter is off. Therefore, if the anole changes color when the ceramic heat emitter is off and the light is on, it will be deemed for thermoregulation purposes because it senses the light, and is trying to absorb more heat from the light by turning darker.

For all stimuli, the anoles will be recorded with a video camera so that they can be observed and data can be collected without lifting the cover and disturbing the anoles. The footage will be reviewed after testing so that data can be recorded.

Pre Analysis Plan

The frequency and duration of color change will be recorded for each variable, and once all of the data is gathered, the results will be compared. The causation of the color change is not exclusive, so it can be deemed that multiple stimuli are equally responsible for the change. Color will be scored as a ratio of green to brown intensities, where a larger score indicates a greener color.