Meeting Abstract
Maternal effects are important mechanisms generating phenotypic variation in offspring with potentially adaptive consequences. Prenatal maternal effects often are mediated through maternal transmission of hormones to the developing embryo. Such effects are particularly well-studied in response to maternally derived steroid hormones. Thyroid hormones (TH), triiodothyronine (T3) and thyroxine (T4), are metabolic hormones having pleiotropic effects across several different life stages. During vertebrate development, THs are critically important for normal development, growth, and metabolism. Recently maternally-derived THs have been shown to vary among individual birds in association with some environmental characteristics including ambient temperature and reproductive timing, and among eggs within a single clutch. Therefore, although data are limited, the possibility exists that maternally-derived THs represent another mode through which adaptive plasticity could arise in offspring. Currently very few studies have examined the potential role of THs in regulating offspring phenotypes; and all studies to date have involved two taxa (birds and turtles) and even fewer have examined such effects in wild animals. We manipulated T3 concentration in eggs of the Prairie Lizard to test for variation in embryonic and hatchling phenotypes potentially related to fitness. T3 manipulation doesn’t appear to dramatically affect embryonic traits but causes sex-specific responses in several hatchling phenotypes potentially related to fitness. In addition, hatchling phenotypes show dose-specific responses. In all, it appears that maternally derived THs can potentially serve as a source of adaptive plasticity in lizards.
