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Within any given clade, male size and female size typically covary, but male size often varies more than female size. This generates a pattern of allometry for sexual size dimorphism (SSD) known as Rensch's rule. I use allometry for SSD among populations of the water strider Aquarius remigis (Hemiptera, Gerridae) to test the hypothesis that Rensch's rule(More)
Trade-offs are a core component of many evolutionary models, particularly those dealing with the evolution of life histories. In the present paper, we identify four topics of key importance for studies of the evolutionary biology of trade-offs. First, we consider the underlying concept of 'constraint'. We conclude that this term is typically used too(More)
A prominent interspecific pattern of sexual size dimorphism (SSD) is Rensch's rule, according to which male body size is more variable or evolutionarily divergent than female body size. Assuming equal growth rates of males and females, SSD would be entirely mediated, and Rensch's rule proximately caused, by sexual differences in development times, or sexual(More)
Sexual size dimorphism (SSD) is often attributed to sexual selection, particularly when males are the larger sex. However, sexual selection favoring large males is common even in taxa where females are the larger sex, and is therefore not a sufficient explanation of patterns of SSD. As part of a more extensive study of the evolution of SSD in water striders(More)
Males of some cannibalistic species of spiders and insects appear to sacrifice themselves by allowing the female to eat them, and the adaptive significance of such drastic terminal reproductive investment has recently been demonstrated for a spider. Typically, the female has to kill the male, but it has been suggested that males of some species in the(More)
We artificially selected for body size in Drosophila melanogaster to test Lande's quantitative genetic model for the evolution of sexual size dimorphism. Thorax width was used as an estimator of body size. Selection was maintained for 21 generations in both directions on males only, females only, or both sexes simultaneously. The correlated response of(More)
Sexual dimorphism (SD) is a defining feature of gonochorous animals and dioecious plants, but the evolution of SD from an initially monomorphic genome presents a conundrum. Theory predicts that the evolution of SD will be facilitated if genes with sex-specific fitness effects occur on sex chromosomes. We review this theory and show that it generates three(More)
Male genital morphology in insects and arachnids is characterized by static hypoallometry and low intrapopulational levels of phenotypic variation relative to other male traits. The one-size-fits-all model of genital evolution attributes these patterns to stabilizing sexual selection. This model relies on the assumption that the observed patterns of(More)
Ridley (1983) proposed that three factors are necessary and sufficient for the development of positive assortative mating (homogamy) in natural populations. These factors are 1) a correlation between male size and success in competition for mates (intrasexual selection), 2) a correlation between female size and fecundity, and 3) prolonged pairing. In the(More)
This paper considers the developing role between VRML and cartography and attempts to add context to it. It does not intend to provide an exhaustive list of geographic VRML applications. Rather it offers examples that illustrate the range of types of cartographic representation that have been developed, and illustrates that whilst VRML could be considered(More)