Thermal plasticity due to parental and early-life environments in the jacky dragon (Amphibolurus muricatus).

Abstract

Developmental plasticity creates marked variation in individual phenotypes when the environment is patchy, such as when the thermal environment varies. Plasticity may occur in response to the environment experienced during an individual's lifetime or to the environment experienced by parents (transgenerational plasticity), and may be adaptive if it enhances fitness. In particular, plasticity in thermal traits, such as preferred temperatures and thermal limits, may improve performance and fitness based on temperatures in the local environment. This study examined the influence of parental and offspring thermal environments (duration of access to a basking lamp) on offspring thermal traits (preferred temperatures and panting threshold) in jacky dragons (Agamidae: Amphibolurus muricatus). Long-bask parental environments led, indirectly, to higher preferred temperatures of offspring due to increased offspring body mass compared to offspring of short-bask parents. The increase in median temperature preference was associated with a higher voluntary minimum body temperature and a narrower preference range, suggesting tradeoffs in thermal behavior and a matching of offspring preferences to the parental environment. Parental thermal treatment did not influence offspring panting threshold. Instead, the panting threshold tended to be higher in offspring that were reared in the long-bask treatment compared to those in the short-bask treatment, suggesting longer basking environments increased thermal tolerance. Parental and offspring thermal environment did not exhibit any interactive effect on thermal traits. The results indicate that thermal environments experienced by lizards can have both transgenerational and within-generation impacts on thermal traits, thus influencing how populations respond to fluctuating or changing climates.