The negative co‐variation of life‐history traits such as fecundity and lifespan across species
suggests the existence of ubiquitous trade‐offs. Mechanistically, trade‐offs result from the …

The steroid hormone testosterone (T) plays a central role in the regulation of breeding in
males, because many physiological, morphological and behavioural traits related to …

Life history theory seeks to explain the evolution of the major features of life cycles by
analyzing the ecological factors that shape age-specific schedules of growth, reproduction …

In spite of recent interest in sexual selection in females, debate exists over whether traits that
influence female–female competition are sexually selected. This review uses female–female …

Adaptationist models of human mating provide a useful framework for identifying subtle,
biologically based mechanisms influencing cross-gender social interaction. In line with this …

Winning aggressive disputes can enhance future fighting ability and the desire to seek out
additional contests. In some instances, these effects are long lasting and vary in response to …

Hormones coordinate the co-expression of behavioral, physiological, and morphological
traits, giving rise to correlations among traits and organisms whose parts work well together …

Testosterone (T) regulates many traits related to fitness, including aggression. However,
individual variation in aggressiveness does not always relate to circulating T, suggesting …

The steroidal regulation of vertebrate neuroanatomy and neurophysiology includes a
seemingly unending list of brain areas, cellular structures and behaviors modulated by these …

Highlights•Testosterone (T) is thought to integrate phenotypes that work well
together.•However, it is not clear how such integration is generated within the organism.•T …