Sexual dimorphism in ecologically relevant traits is ubiquitous in animals. However, other types of intraspecific phenotypic divergence, such as trophic polymorphism, are less common. Because linkage to sex should often lead to balancing selection, understanding the association between sex and phenotypic divergence could help explain why particular species show high morphological variability. T...

BACKGROUND Sexual dimorphism represents a group of morphologic characteristics that differentiate a male from a female. Among these dimorphic traits, tooth size has been evaluated in various populations for its interest in anthropologic and forensic applications. Recent studies have shown that dental dimorphism is population-specific and that the most dimorphic tooth is the mandibular canine. I...

1. The evolution of sexual dimorphism presents a challenge because males and females must express two phenotypes from the same underlying genome. In vertebrates, one solution to this challenge is to link the expression of shared traits to sex steroids. However, even ‘male-biased’ steroids such as testosterone (T) circulate at biologically significant levels in females, raising the question of w...

Sexual dimorphism, i.e. the distinct recognition of only two sexes per species, is the phenotypic expression of a multi-stage procedure at chromosomal, gonadal, hormonal and behavioral level. Chromosomal--genetic sexual dimorphism refers to the presence of two identical (XX) or two different (XY) gonosomes in females and males, respectively. This is due to the distinct content of the X and Y-ch...

Sexual size dimorphism is widespread among animals; males are larger than females in most birds and mammals whereas the opposite is true among invertebrates, amphibians and reptiles (Andersson 1994, Fairbairn 1997). These taxonomic differences have influenced the terminology and prevailing hypotheses for dimorphism. Although sexual size dimorphism is often described as “normal-” or “reversed-” ...

Differences in selective pressures and the energetic cost of gametes gonochoristic corals should vary with sex colony, which may lead to sexual dimorphism. Coral colonies are composed subunits (corallites) that create a complex morphological architecture. If corallite features distinct between sexes, then degree coordinated change among these also (phenotypic modularity). This study tested for ...

Within the large order of bats, sexual size dimorphism measured by forearm length and body mass is often female-biased. Several studies have explained this through the effects on load carrying during pregnancy, intrasexual competition, as well as the fecundity and thermoregulation advantages of increased female body size. We hypothesized that wing shape should differ along with size and be unde...

Symmetry and masculinity in human faces have been proposed to be cues to the quality of the owner. Accordingly, symmetry is generally found attractive in male and female faces and femininity is attractive in female faces. Women’s preferences for male facial masculinity vary in ways that may maximise genetic benefits to women’s offspring. Here we examine sameand opposite-sex preferences for both...