The effect of short-term weather fluctuations on temperatures inside lizard nests, and on the phenotypic traits of hatchling lizards

Can short-term stochastic variation in local weather conditions modify the thermal conditions inside lizard nests, and thus (potentially) the developmental rates, hatching success, and phenotypic traits of hatchlings from these nests? This hypothesis requires that (i) natural nests are poorly buffered thermally, such that ambient regimes affect temperatures inside the nest, and (ii) short-term thermal variations modify attributes of the offspring. Field data on natural nests of the sub-alpine skink Bassiana duperreyi confirm the existence of this first effect, and laboratory experiments substantiate the latter. Exposure to warmer-than-usual temperatures for 2 weeks during the 9- to 16-week incubation period doubled hatching success, and significantly modified hatchling phenotypes (hatching dates, offspring size and locomotor performance). The proportion of development completed prior to this exposure influenced the degree of response. Exposure to a brief 'window' of higher-than-usual temperatures soon after oviposition had more effect on hatching time, egg survival and hatchling phenotypes than if the exposure occurred later in development. Thus, minor variations in weather conditions during incubation may have substantial effects on reptile populations.