Abstract
Natural populations respond to selection pressures like increasing local temperatures in many ways, including plasticity and adaptation. To predict the response of ectotherms like lizards to local temperature increase, it is essential to estimate phenotypic variation in and determine the heritability of temperature-related traits like average field body temperature (T b) and preferred temperature (T p). We measured T p of Uta stansburiana in a laboratory thermal gradient and assessed the contribution of sex, reproductive status and throat color genotype to phenotypic variation in T b of adult lizards. Females had higher T p than males. However, they temporarily preferred lower temperature when gravid than when nongravid. Using a nested half-sib design for genetic crosses in the laboratory, we estimated relative contributions of additive genetic variation and maternal effects to T p of hatchlings. Our results show that maternal effects, but not additive genetic variation, influence T p of hatchlings in U. stansburiana. Maternal T p and the presence or absence of blue throat color alleles significantly influenced T p of hatchlings. We discuss ecological and evolutionary consequences of these maternal effects in the context of rapid climate change and natural selection that we measure on progeny survival to maturity as a function of maternal T p.