Data from: Linking warmer nest temperatures to reduced body size in seabird nestlings: Possible mitochondrial bioenergetic and proteomic mechanisms

Rapid reduction of body size in populations responding to global warming
suggests the involvement of temperature-dependent physiological
adjustments during growth, such as mitochondrial alterations in the
efficiency of producing metabolic energy, a process that is poorly
explored, especially in endotherms. Here, we examined the mitochondrial
metabolism and proteomic profile of red blood cells in relation to body
size and cellular energy production in nestling shearwaters (Calonectris
diomedea) developing at different temperatures. Despite not spending more
energy to thermoregulate (invariant cell metabolic rate), their
mitochondria had a higher inefficiency in coupling metabolism to energy
production, as evidenced by bioenergetic and proteomic analyses.
Mitochondrial inefficiency was positively related to cellular stress
represented by heat shock proteins, antioxidant enzymes, and markers of
mitochondrial stress. The observed temperature-related mitochondrial
inefficiency was associated with reduced beak size and body mass and was
linked to the downregulation of cellular growth factors and growth
promoters determining body size. Nestlings of warmer nests had lighter
bodies and smaller beaks at fledging. By analyzing the links between
environmental temperature, mitochondrial inefficiency, and body size we
discuss the physiological alterations that free-living birds, and probably
other endotherms, need to trigger to cope with a warming world.