Meeting Abstract
Hibernation provides a highly programmed means of escaping the metabolic and food availability challenges associated with seasonality, but the ability of small mammalian hibernators to adjust their timing of seasonal dormancy in response to extreme weather events is unclear. Here, we show that arctic ground squirrels in Northern Alaska exhibited sex-dependent plasticity in the spring-time physiology and phenology of hibernation-end in response to a series of late spring snowstorms in 2013 that resulted in the latest date of snow-melt on record. Females and non-reproductive males responded to the >1 month delay in snow-melt by extending heterothermy or re-entering hibernation after several days of euthermy, leading to a >2-week delay in reproduction compared to surrounding years. Females increased the frequency of arousal episodes and assessed above ground conditions, presumably the extent of snow-cover, before committing to above-ground activity and reproduction. In contrast, reproductive males neither extended nor re-entered hibernation and emerged from hibernation normally, likely because seasonal gonadal growth and development and subsequent testosterone release prevents a return to torpor. Our findings reveal intriguing differences in responses of males and females to climatic variability that can generate a phenological mismatch between the sexes.
