Do gravid female Anolis nebulosus thermoregulate differently than males and non-gravid females?

Abstract

In lizards, the role of gravid oviparous females in controlling the temperature experienced by developing embryos prior to oviposition has been rarely examined. In particular, relatively little is known about the effect of gravidity on the thermal ecology of female Anolis lizards. Here we examine the thermal ecology of Anolis nebulosus from Nayarit, Mexico, with a particular goal of comparing the thermal ecology of gravid females to that of non-gravid females and males. The thermal efficiency (E) of gravid female A. nebulosus (E=0.782) was higher than in males (E=0.464), and to a lesser extent, non-gravid females (E=0.637), despite no significant differences observed in body, air, operative, or set point temperatures among males, gravid females, and non-gravid females. Gravid females had smaller differences between body temperatures and set point temperatures (db), but did not differ in the difference between operative temperature and set point temperature (de). Gravid females used sun-shade and shaded microhabitats proportionately more than males and non-gravid females, and rarely used sunny microhabitats. Our results suggest that gravid A. nebulosus are using a different and more efficient thermoregulatory strategy than other adults in the population. Such efficient thermoregulation is possibly related to females attempting to provide a thermal environment that is conducive to the development of embryos in eggs prior to oviposition.