The study of phenotypic evolution should be an integrative endeavor that combines different
approaches and crosses disciplinary and phylogenetic boundaries to consider complex …

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 …

Relationships between morphology, physiology, or biochemistry, on the one hand, and
behavior and ecology, on the other, have been widely documented, as this volume attests …

" The objectives of comparative physiology are:(1) to describe the diverse ways which
different kinds of animals meet their functional requirements;(2) to elucidate evolutionary …

We examined the hypothesis that increased aggression results in decreased survivorship.
We tested this hypothesis by increasing aggression of free-living male lizards Sceloporus …

The challenge hypothesis (JC Wingfield, RE Hegner, BG Ball, and AM Duffy, 1990, Am. Nat.
136, 829–846) proposes that in birds, reptiles, and fish,“the frequency or intensity of …

One of the primary assumptions of the immunocompetence hypothesis is that testosterone is
immunosuppressive. Although many studies in birds and mammals have supported this …

Physiological capacities may constrain behavioural options and hence have important
ecological consequences. We tested the hypothesis that social dominance is related to …

Extensive research has focused on territorial aggression during the breeding season and
the roles of circulating testosterone (T) and its conversion to 17β–oestradiol (E2) in the brain …

Fitness tradeoffs are difficult to examine because many fitness variables are correlated and
vary in the same direction. Phenotypic manipulation circumvents many of these difficulties …