Degree of anisogamy is unrelated to the intensity of sexual selection

Scientific Reports, Journal Year: 2021, Volume and Issue: 11(1)

Published: Sept. 30, 2021

Abstract Males and females often display different behaviours and, in the context of reproduction, these are labelled sex roles. The Darwin–Bateman paradigm argues that root differences is anisogamy (i.e., size and/or function gametes between sexes) leads to biased sexual selection, parental care body size. This evolutionary cascade, however, contentious since some underpinning assumptions have been questioned. Here we investigate relationships anisogamy, dimorphism, difference intensity selection using phylogenetic comparative analyses 64 species from a wide range animal taxa. results question first step paradigm, as extent does not appear predict selection. only significant predictor relative inputs males into offspring. We propose ecological factors, life-history demography more substantial impacts on contemporary roles than gametic investments sexes.

Language: Английский

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Sexual dimorphism driven by intersexual resource competition: Why is it rare, and where to look for it?

Journal of Animal Ecology, Journal Year: 2021, Volume and Issue: 90(8), P. 1831 - 1843

Published: March 24, 2021

Abstract Sexes often differ more obviously in secondary sexual characteristics than traits that appear naturally selected, despite conceivable benefits to intersexual niche partitioning. Genetic constraints may play a role limiting sex‐specific evolution; however, it is not clear why this limit should apply selected those under selection; the latter routinely produces dimorphism. We ask whether ecological factors and/or features of mating system dimorphism resource use, or conversely, what conditions are most permissible ones for differences. The scale competition and spatial variation availability can help predict sexually dimorphic niches lack thereof. investigate when might fail evolve even if genetic covariation between sexes posed no constraint. Our analytical model incorporates first aspect interactions (scale competition). It followed by simulations explore broader conditions, including multiple resources with habitat heterogeneity, correlations non‐Gaussian resource‐use efficiency functions. recover earlier known favourable evolution partitioning sexes, such as narrow individual low degrees also show considerations alter picture. Sexual divergence occurs readily local groups small different occur reliably across habitats. Polygyny (medium‐sized large groups) diminish prospects present. Habitat heterogeneity typically disfavours but lead polymorphism within sex, beneficial specialize be very competitive one habitat, at cost performance other. conflict usually used explain behaviours. models highlight introducing (achieved switching from monogamy polygamy) responsible monomorphism. Under monogamy, males benefit specializing consume other feeds female best. makes disregard benefit, both compete profitable resource, leading overlapping niches.

Language: Английский

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Sexual selection moderates heat stress response in males and females

Functional Ecology, Journal Year: 2022, Volume and Issue: 36(12), P. 3096 - 3106

Published: Oct. 18, 2022

A widespread effect of climate change is the displacement organisms from their thermal optima. The associated stress imposed by has been argued to have a particularly strong impact on male reproduction but evidence for this postulated sex-specific response equivocal.One important factor that may explain intra- and interspecific variation in responses sexual selection, which predicted magnify negative effects stress. Nevertheless, empirical studies exploring interplay selection heat are still scarce.We tested experimentally an interaction between red flour beetle

Language: Английский

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Rapid evolution of ecological sexual dimorphism driven by resource competition

Ecology Letters, Journal Year: 2022, Volume and Issue: 26(1), P. 124 - 131

Published: Nov. 10, 2022

Sex differences in ecologically important traits are common animals and plants, prompted Darwin to first propose an ecological cause of sexual dimorphism. Despite theoretical plausibility Darwin's original notion, a role for resource competition the evolution dimorphism has never been directly demonstrated remains controversial. I used experimental Drosophila melanogaster test hypothesis that can drive sex diet. Following just three generations adaptation, offspring from flies evolved low-resource, high-competition environments show elevated diet preference compared both ancestor populations on high-resource availability. This increased was result divergence male sucrose intake female yeast consistent with differential nutritional requirements sexes. These results provide real-time direct evidence driven by competition.

Language: Английский

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Allele frequency dynamics under sex-biased demography and sex-specific inheritance in a pedigreed jay population

Genetics, Journal Year: 2024, Volume and Issue: 227(3)

Published: May 9, 2024

Abstract Sex-biased demography, including sex-biased survival or migration, can alter allele frequency changes across the genome. In particular, we expect different patterns of genetic variation on autosomes and sex chromosomes due to sex-specific differences in life histories, as well effective population size, transmission modes, strength mode selection. Here, demonstrate role that history played shaping short-term evolutionary dynamics We used a 25-year pedigree genomic dataset from long-studied Florida Scrub-Jays (Aphelocoma coerulescens) directly characterize relative roles demography inheritance genome-wide trajectories. gene dropping simulations estimate individual contributions future generations model drift immigration known pedigree. quantified differential expected males females over time, showing impact dispersal monogamous system. Due female-biased dispersal, more autosomal is introduced by female immigrants. However, male-biased transmission, Z male Finally, partitioned proportion variance change through time contributions. Overall, most births. Males make similar change, but higher chromosome. Our work shows importance understanding demographic processes characterizing wild populations.

Language: Английский

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Pre‐Copulatory Sexual Selection Predicts Sexual Size Dimorphism: A Meta‐Analysis of Comparative Studies

Ecology Letters, Journal Year: 2024, Volume and Issue: 27(9)

Published: Sept. 1, 2024

Size differences between males and females are common across the tree of life (termed sexual size dimorphism; SSD), have fundamental implications for ecology, history behaviour both sexes. Conventionally, SSD is thought to evolve in response sex-specific selection but more recent work suggests that ecological processes can also promote sex-differences size. Here, we provide a global test role evolution dimorphism using data from 77 comparative studies spanning major classes animal kingdom. We show intense typically correlates with male-biased species. Importantly, pre-copulatory not post-copulatory predicts SSD, suggesting pervasive premating male-male competition female choice drive sex body Collectively, our findings suggest plays SSD.

Language: Английский

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Ecology, sexual dimorphism, and jumping evolution in anurans

Journal of Evolutionary Biology, Journal Year: 2023, Volume and Issue: 36(5), P. 829 - 841

Published: May 1, 2023

Sexual dimorphism (SD) is a common feature of animals, and selection for sexually dimorphic traits may affect both functional morphological organismal performance. Trait evolution through natural can also vary across environments. However, whether the performance distinct between sexes rarely tested in phylogenetic comparative context. Anurans commonly exhibit sexual size dimorphism, which jumping given effects body on locomotion. They live wide variety microhabitats. Yet relationships among performance, ecology remain underexamined anurans. Here, we explore microhabitat use, size, males females to determine drivers patterns Using methods predicting anatomical measurements, describe how fecundity associated with have likely shaped female We found that magnitude (where are about 14% larger than males) was much lower muscle volume, where had 42% more (after accounting size). Despite these sometimes-large averages, t-tests failed show statistical significance SD any variable, indicating species tend be closely related. While did not microhabitats, velocity energy differed Overall, our findings indicate differences sex-specific reproductive roles, jumping-related morphology, all important determinants has led incredible ecophenotypic diversity

Language: Английский

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Observable variations in human sex ratio at birth

PLoS Computational Biology, Journal Year: 2021, Volume and Issue: 17(12), P. e1009586 - e1009586

Published: Dec. 2, 2021

The human sex ratio at birth (SRB), defined as the between number of newborn boys to total newborns, is typically slightly greater than 1/2 (more girls) and tends vary across different geographical regions time periods. In this large-scale study, we sought validate previously-reported associations test new hypotheses using statistical analysis two very large datasets incorporating electronic medical records (EMRs). One represents over half (∼ 150 million) US population for 8 years (IBM Watson Health MarketScan insurance claims) while another covers entire Swedish 9 30 (the National Patient Register). After testing more 100 hypotheses, showed that neither dataset supported models in which SRB changed seasonally or response variations ambient temperature. However, increased levels a diverse array air water pollutants, were associated with lower SRBs, including industrial agricultural activity, served proxies pollution. Moreover, some exogenous factors generally considered be environmental toxins turned out induce higher SRBs. Finally, identified signals either all cases, effect sizes modest but highly statistically significant owing datasets. We suggest it was unlikely have arisen from sex-specific selection mechanisms, they are still useful purpose public health surveillance if can corroborated by empirical evidences.

Language: Английский

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Can diet niche partitioning enhance sexual dimorphism?

Ecology and Evolution, Journal Year: 2022, Volume and Issue: 12(12)

Published: Dec. 1, 2022

Classic evolutionary theory suggests that sexual dimorphism evolves primarily via and fecundity selection. However, evidence are beginning to accumulate suggesting resource competition can drive the evolution of dimorphism, ecological character displacement between sexes. A key prediction this hypothesis is extent divergence sexes will be associated with dimorphism. As stable isotope ratios animal tissues provide a quantitative measure various aspects ecology, we carried out meta-analysis examining associations isotopic body size Our models demonstrate large amounts between-study variation in (ecological) nonrandom may traits study subjects. We, therefore, completed meta-regressions examine whether We found modest but significantly positive across species differences sexes, increased strength when opportunity for dietary was greatest. results, further ecologically mediated selection, not directly related reproduction, contribute

Language: Английский

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Effects of time spent in pregnancy or brooding on immunocompetence

Ecology and Evolution, Journal Year: 2024, Volume and Issue: 14(1)

Published: Jan. 1, 2024

Sexes of a species may show different characteristics beyond the differences in their sexual organs and such dimorphism often occurs level immune response when exposed to pathogens (immunocompetence). In general, females have increased longevity relative males, which is associated with higher immunocompetence. However, males immunocompetence some species, as pipefishes seahorses. Experimental evidence suggests that this could be because rather than females, carry fertilized eggs birth these species. This observation an increase related parental investment not particular sex. We use state-dependent life-history theory study optimal offspring production parent immunocompetence, varying time spends brooding or pregnancy within breeding cycle. When dependent on parent's survival for large part cycle, we predict investments immunity longer life expectancies.

Language: Английский

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