Meeting Abstract
The parietal eye is a photosensitive structure with a well-developed cornea, retina, and lens, located on the top of the head in some species of lizards. In combination with the pineal complex above which it is located, the parietal eye plays a role in the secretion of melatonin which is important for the lizard to be able to regulate awake/sleep cycles as well as thermoregulation. The secretion of melatonin is dependent on the ability of the parietal eye to sense UVb rays. When the parietal eye is removed or covered, there are significant alterations in the lizard’s ability to thermoregulate both behaviorally and physiologically. Our research question focused on the effect of masking the parietal eye on normal baseline behaviors regarding light (UVb) and heat preference of the bearded dragon Pogona vitticepes and the green anole Anolis carolinensis. The objectives of our research were to observe basking behavior under UVb and infrared heat light and to determine the amount of time spent under each bulb, under normal baseline behaviors and when light detection by the parietal eye of all subjects was inhibited with a non-toxic black paint. The black paint disrupted the light signal from reaching the parietal eye, and the light information was not processed by the pineal complex, hence disrupting normal baseline behaviors. Basking time data was collected from a video camera which recorded the lizards activity during the day. Baseline behaviors including locomotor activity only before and during feeding were observed every hour for a week. Masking the parietal eye disrupted the stereotypical baseline behaviors observed in both species of lizard, demonstrating the importance of this sensory structure to the everyday physiological needs of these animals.
