Darwin developed the theory of sexual selection to account for the evolution of weaponry,
ornamentation and other secondary sexual characters that are commonly more developed …

Methods to measure metabolites of steroid hormones from faeces have become very
popular in wildlife conservation and ecology, because they allow gathering physiological …

Sexual and asexual reproduction are found throughout the plant and animal kingdoms.
Asexual reproduction has its advantages, chief among which is that it does not require the …

Research into the lives of animals in their natural environments has revealed a rich tapestry
of complex social relationships and previously unsuspected social and mating systems. The …

For sexual selection to act on a given sex, there must exist variation in the reproductive
success of that sex as a result of differential access to mates or fertilisations. The …

When selection on males and females differs, the sexes may diverge in phenotype.
Hormones serve as a proximate regulator of sex differences by mediating sex-biased trait …

During the past several years, the noninvasive measurement of steroid metabolites from
mammalian feces and bird droppings has become more and more popular. With an …

Publisher Summary This chapter discusses the physiology, ecology, and behavior of
hormones in avian eggs. The main source of hormones found in avian eggs is the maturing …

In almost all songbird species studied males sing, but differences in female song range from
species where females have never been observed to sing to those where females sing as …

In this paper we provide a critical review of research concerned with social/environmental
mechanisms that modulate human neuroendocrine function. We survey research in four …