Allometric scaling and social modulation of resting metabolic rate in a eusocial mammal (Heterocephalus glaber)

Abstract

Resting metabolic rate (RMR) underpins energy allocation to survival, reproduction, and longevity, yet its drivers in highly structured social systems remain unclear. We measured RMR in 76 naked mole-rats (Heterocephalus glaber) from five colonies to test effects of body mass, sex, reproductive status, age, social rank, and colony stability in this eusocial mammal. Body mass was the strongest predictor of RMR. Nevertheless, absolute RMR values were far below those predicted for mammals of similar mass, confirming metabolic suppression in this strictly subterranean species. Social factors produced subtler patterns. Among non-breeders, males had slightly higher (but not significantly so) RMR than females despite similar body mass. Breeding females showed elevated RMR relative to non-breeding females, but not significantly so. Age and dominance rank did not influence RMR once body mass was controlled. Colony identity explained little variation overall, although one colony showed altered metabolic scaling after social conflict, suggesting colony-level metabolic plasticity associated with hierarchical instability.