Scincella lateralis (Little Brown Skink) is a fossorial species of reptile distributed throughout much of the subtropical climate zone. The cost of thermoregulating for the Little Brown Skink is higher than that of other larger lizards as it is unable to exercise physiological control of its conductance due to its small size. Therefore, smaller lizards would have to depend on behavioral thermoregulatory strategies. As thermoconformers, the Little Brown Skink could spend less time on behavior strategies and allocate resources more appropriately. Thermoconformity was found to be the most advantageous for the Little Brown Skink, inhabiting regions where temperatures were invariant throughout the year. Competing thermoregulatory models (thermoregulation vs. thermoconforming) in the Little Brown Skink have been thoroughly discussed; however, our research design hopes to expand the scope of the discussion and move the consensus towards a decisive conclusion. We conducted two studies as part of this project: 1) to record field active body temperatures and 2) to determine the species’ critical thermal minimum temperature.
Results/Conclusions
We discovered that Little Brown Skinks are most likely thermoconformers according to our two-tailed T-test; it provided statistical evidence that substrate temperatures and cloacal temperatures were not significantly different. Additional evidence of thermoconformity is seen in the coefficient of determination, showing that ~77% of variation in cloacal temperature is related to substrate temperature. The random distribution of points found in the scatterplot of residuals further indicates thermoconformity. The overall righting temperatures of the Little Brown Skinks ranged from 20.8 - 28.6 C with snout-to-vent lengths of individual lizards ranging from 2.3 - 4.5 cm. The coefficient of determination was 0.10, which does not support a strong relationship. However, the trend line shows a slight negative slope, which could offer some support for a decreasing critical thermal minimum with increasing body length. In conclusion, thermal biology shows great diversity in ecological strategies, and thermoregulating or thermoconforming behavioral adaptations will vary based on environmental conditions. Our data supports thermoconformity in the Little Brown Skink.