Meeting Abstract
Climate change is causing increases in temperature mean and variance. Organisms may respond to temperature changes during development, but few studies have examined physiology of early life stage as a mechanism to mediate the impacts of climate change. Using the dung beetle Onthophagus taurus, we investigated the potential of metabolic depression in an early life stage to buffer beetles from climate change. Specifically, we examined the effects of increasing temperature mean and variation on metabolism of pupae and fitness of adults using body size as a proxy. We reared beetles in nine incubation treatments using a full factorial design: three averages (22, 24, 26°C) and three fluctuations (±2, ±4, ±8°C) in temperature. At pupation, we measured thermal sensitivity of metabolism (TSM), the relationship between temperature and metabolic rate. We reared beetles to adulthood and measured body size. The relationship between temperature and metabolic rate was affected by developmental incubation; temperature mean and variation interact to influence pupae TSM (p= 0.002). Beetles reared in the warmest, most variable treatment exhibited significant metabolic depression across temperatures and significantly smaller body size. Thus, the reduction in energetic costs showed a tradeoff with body size. These findings suggest plasticity in early life stages can help beetles cope with thermal environments during development, but this may come at a cost to fitness later in life.
