Sexual size dimorphism (SSD) is common in both plants and animals, current evidence suggests that it reflects the adaptation of males females to their different reproductive roles. When species are compared within a clade, SSD frequently found vary with body size. This allometry detected as β ≠ 1, where slope model II regression log(male size) on log(female size). Most frequently, exceeds indicating increases larger sex, but decreases larger, trend formalized “Rensch's rule.” Exceptions...

Summary 1. Researchers frequently take repeated measurements of individuals in a sample with the goal quantifying proportion total variation that can be attributed to among vs. within individuals. The is known as repeatability and most estimated intraclass correlation coefficient (ICC). our study provide guidelines for determining size (number number per individual) required accurately estimate ICC. 2. We report range ICCs from literature 95% confidence intervals these estimates. introduce...

SECTION I: MACRO-PATTERNS: EXPLAINING BROAD-SCALE PATTERNS OF VARIATION IN SEXUAL SIZE DIMORPHISM II: MICRO-PATTERNS: CASE STUDIES AND EVOLUTIONARY PROCESSES WITHIN AMONG SPECIES III: PROXIMATE DEVELOPMENTAL GENETIC MECHANISMS

Rensch's rule states that sexual size dimorphism (SSD) increases with body (hyperallometry) in taxa which males are the larger sex and decreases (hypoallometry) those females larger. We use independent contrasts method to assess validity generality of within 21 animal taxa. Allometry is estimated as slope major axis regression for log(female size) versus log(male size). consistent significant 33% examined across a diverse range invertebrate vertebrate Significant allometry inconsistent...

Many species of insects exhibit wing dimorphism, one morph having fully developed wings and the other reduced being incapable flight. These dimorphisms provide visible manifestations migratory polymorphisms. Since winged individuals do not, in principle, have to fly, existence forms with suggests that there is a tradeoff between flight capability fitness components. Comparisons life histories morphs demonstrate this most commonly expressed as decrease age first reproduction increased...

A prominent interspecific pattern of sexual size dimorphism (SSD) is Rensch's rule, according to which male body more variable or evolutionarily divergent than female size. Assuming equal growth rates males and females, SSD would be entirely mediated, rule proximately caused, by differences in development times, bimaturism (SBM), with the larger sex developing for a proportionately longer time. Only subset seven arthropod groups investigated this study exhibits rule. Furthermore, we found...

Sexual size dimorphism (SSD) typically increases with body (hyperallometry) in taxa which males are the larger sex and decreases (hypoallometry) females larger. We demonstrate commonality of these trends, both indicate greater evolutionary divergence male than female strong covariation between sexes. postulate that components allometry evolve response to sexual selection on coupled genetic correlations for females, we argue this hypothesis can be generalized sex. For such taxa, predict...

Within any given clade, male size and female typically covary, but often varies more than size. This generates a pattern of allometry for sexual dimorphism (SSD) known as Rensch's rule. I use SSD among populations the water strider Aquarius remigis (Hemiptera, Gerridae) to test hypothesis that rule evolves in response selection on secondary traits an alternative it is caused by greater phenotypic plasticity body males. Comparisons three reared under two temperature regimes are combined with...

Because areas suitable for growth and reproduction are often ephemeral, a primary selective force in the evolution of migratory behavior insects is need to colonize new habitats. However, both migration itself flight capability reduce present reproductive success. Thus long-term fitness benefit migration, colonization habitats, balanced by short-term reduction fitness, result being that variation ability preserved population. Migration but one component wide suite functionally connected...

Abstract We addressed the general hypothesis that life history differences among eastern populations of North American water strider, Aquarius remigis (Heteroptera: Gerridae), along a north‐south gradient are manifestations genetic differentiation due to natural selection. raised offspring two field‐caught from each three latitudes in common laboratory environment at 20° C and photoperiods. Nearly all Quebec (PQ) individuals (ca. 46° N) entered diapause reproduce following spring (univoltine...

Sexual size ratios (mean female length divided by mean male length) of 12 species temperate waterstriders in the subfamily Gerrinae (Hemiptera, Gerridae) are analyzed to test both potentially nonadaptive and adaptive hypotheses for evolution sexual dimorphism. Females tend be larger than males, regression on (both log-transformed) reveals significant hypoallometry Both explanations this allometry discussed. Of these, only a model is consistent with available data. Two closely related genera,...

Abstract Lande’s (1980b, Evolution34: 292–305) equations for predicting the evolution of sexual size dimorphism (SSD) through frequency-dependent selection, and frequency-independent natural were tested against results obtained from a stochastic genetic simulation model. The SSD evolved faster than predicted, due to temporary increases in variance brought about by directional selection. Predictions magnitude at equilibrium very accurate weak With stronger selection total response was greater...

Males of some cannibalistic species spiders and insects appear to sacrifice themselves by allowing the female eat them, adaptive significance such drastic terminal reproductive investment has recently been demonstrated for a spider. Typically, kill male, but it suggested that males in orb-weaving spider genus Argiope may die copula without 'collaboration'. Here, we provide first experimental evidence our knowledge programmed sudden death after onset copulation aurantia. Our observations...

Sexual size dimorphism (SSD) is often attributed to sexual selection, particularly when males are the larger sex. However, selection favoring large common even in taxa where females sex, and therefore not a sufficient explanation of patterns SSD. As part more extensive study evolution SSD water striders (Heteroptera, Gerridae), we examine 12 populations Aquarius remigis. We calculate univariate multivariate gradients from samples mating single males, for two sexually dimorphic traits (total...

Abstract Sexual size dimorphism is assumed to be adaptive and expected evolve in response a difference the net selection pressures on sexes. Although demonstration of sexual neither necessary nor sufficient explain evolution dimorphism, generally major evolutionary force. If contemporary important maintenance then we expect see concordance between patterns dimorphism. We examined wild, acting male body size, components waterstrider Aquarius remigis , as part long term study examining two...

Demographic processes associated with the onset of breeding in spring are examined a population deer mice, Peromyscus maniculatus. Many mice both sexes disappear from at this time. The disappearance males appears to result dispersal light-weight, subordinate animals. females, however, be due mainly mortality early-breeding females. consequences difference between for limitation densities discussed. Two hypotheses relating those females presented, and possible experimental test these is described.

Abstract Despite substantial progress for women in science, remain underrepresented many aspects of the scholarly publication process. We examined how gender diversity editors and reviewers changed over time six journals ecology evolution (2003–2015 four journals, 2007–2015 or 2009–2015 other two), several peer review process differed between female male reviewers. found that five were either absent very poorly represented as handling at beginning our dataset. The representation increased...

Sexual size dimorphism (SSD), the difference in body between males and females, is common almost all taxa of animals generally assumed to be adaptive. Although sexual selection fecundity alone have often been invoked explain evolution SSD, more recent views indicate that sexes must experience different lifetime pressures for SSD evolve maintained. We estimated acting on male female adult (total length) components waterstrider Aquarius remigis during three phases life history. Opposing...