General trends in the thermoregulation of lacertid lizards: a meta-analysis

Temperature plays a big role in evolution, particularly in ectotherms. In addition, the thermoregulation ability may be crucial for lizards to buffer the impact of climate change. Many factors are known to affect lizards’ thermoregulation, probably interacting in a complex model of costs and benefits. Here we integrated previous research on lacertid lizards to assess the importance of different factors in their thermoregulation. We conducted meta-analyses of the three most used effect sizes: (1) difference of means between body and air temperatures, (2) correlation between body and air temperatures, and (3) effectiveness of thermoregulation. We considered habitat, climate, body size, season, altitude, and insularity as potential moderators of the heterogeneity of effect sizes. Seasonality had the greatest effect on body temperature regulation, with a minimum intensity of thermoregulation for summer. Then, altitude plays also an important role, with a direct relationship between altitude and the degree of thermoregulation. Finally, body size may interact with season, but this needs further consideration. In conclusion, season and altitude explain the greatest heterogeneity of effect sizes, and their effects should be considered in detail in future studies. These results improve the understanding about the relative importance of the evolutionary forces that drive the adaptation of lizards to temperature.