Natural Selection and Sexual Selection on Body Size in Red-Winged Blackbirds

Evolution ◽  
1987 ◽  
Vol 41 (6) ◽  
pp. 1401 ◽  
Author(s):  
Patrick J. Weatherhead ◽  
Hamilton Greenwood ◽  
Robert G. Clark
Keyword(s):  
Sexual Selection ◽  
Body Size ◽  
Natural Selection

scholarly journals Body size differences do not arise from divergent mate preferences in a species pair of threespine stickleback

2009 ◽  
Vol 5 (4) ◽  
pp. 517-520 ◽  
Author(s):  
Megan L Head ◽  
Emily A. Price ◽  
Janette W. Boughman
Keyword(s):  
Sexual Selection ◽  
Body Size ◽  
Natural Selection ◽  
Gasterosteus Aculeatus ◽  
Sexual Isolation ◽  
Mate Preferences ◽  
Species Pair ◽  
Divergent Natural Selection ◽  
Relative Contribution ◽  
Threespine Sticklebacks

Ecological speciation can be driven by divergent natural and/or sexual selection. The relative contribution of these processes to species divergence, however, is unknown. Here, we investigate how sexual selection in the form of male and female mate preferences contributes to divergence of body size. This trait is known be under divergent natural selection and also contributes to sexual isolation in species pairs of threespine sticklebacks ( Gasterosteus aculeatus ). We show that neither female nor male size preferences contribute to body size divergence in this species pair, suggesting that size-based sexual isolation arises primarily through natural selection.

scholarly journals NATURAL SELECTION AND SEXUAL SELECTION ON BODY SIZE IN RED-WINGED BLACKBIRDS

Evolution ◽  
1987 ◽  
Vol 41 (6) ◽  
pp. 1401-1403 ◽  
Author(s):  
Patrick J. Weatherhead ◽  
Hamilton Greenwood ◽  
Robert G. Clark
Keyword(s):  
Sexual Selection ◽  
Body Size ◽  
Natural Selection

Darwinian Evolutionary Theory

2018 ◽  
Author(s):  
Michael Ruse
Keyword(s):  
Sexual Selection ◽  
Natural Selection ◽  
Middle Class ◽  
Evolutionary Theory ◽  
Scientific Community ◽  
Homo Sapiens ◽  
Origin Of Species ◽  
Theory Of Evolution ◽  
Descent Of Man

Charles Robert Darwin, the English naturalist, published On the Origin of Species in 1859 and the follow-up work The Descent of Man in 1871. In these works, he argued for his theory of evolution through natural selection, applying it to all organisms, living and dead, including our own species, Homo sapiens. Although controversial from the start, Darwin’s thinking was deeply embedded in the culture of his day, that of a middle-class Englishman. Evolution as such was an immediate success in scientific circles, but although the mechanism of selection had supporters in the scientific community (especially among those working with fast-breeding organisms), its real success was in the popular domain. Natural selection, and particularly the side mechanism of sexual selection, were known to all and popular themes in fiction and elsewhere.

scholarly journals Natural selection increases female fitness by reversing the exaggeration of a male sexually selected trait

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Kensuke Okada ◽  
Masako Katsuki ◽  
Manmohan D. Sharma ◽  
Katsuya Kiyose ◽  
Tomokazu Seko ◽  
...  
Keyword(s):  
Sexual Selection ◽  
Natural Selection ◽  
Experimental Evolution ◽  
Genetic Correlations ◽  
Lifetime Reproductive Success ◽  
Fundamental Theory ◽  
Female Fitness ◽  
Male Trait ◽  
Flour Beetles ◽  
Male Specific

AbstractTheory shows how sexual selection can exaggerate male traits beyond naturally selected optima and also how natural selection can ultimately halt trait elaboration. Empirical evidence supports this theory, but to our knowledge, there have been no experimental evolution studies directly testing this logic, and little examination of possible associated effects on female fitness. Here we use experimental evolution of replicate populations of broad-horned flour beetles to test for effects of sex-specific predation on an exaggerated sexually selected male trait (the mandibles), while also testing for effects on female lifetime reproductive success. We find that populations subjected to male-specific predation evolve smaller sexually selected mandibles and this indirectly increases female fitness, seemingly through intersexual genetic correlations we document. Predation solely on females has no effects. Our findings support fundamental theory, but also reveal unforseen outcomes—the indirect effect on females—when natural selection targets sex-limited sexually selected characters.

Size does not matter for male Marbled Salamanders (Ambystoma opacum)

2015 ◽  
Vol 93 (10) ◽  
pp. 735-740
Author(s):  
D.A. Croshaw ◽  
J.H.K. Pechmann
Keyword(s):  
Sexual Selection ◽  
Body Size ◽  
Reproductive Success ◽  
Large Male ◽  
Male Mating ◽  
Ambystoma Opacum ◽  
Positive Assortative Mating ◽  
Important Trait ◽  
Breeding Groups ◽  
Gravid Females

Understanding the phenotypic attributes that contribute to variance in mating and reproductive success is crucial in the study of evolution by sexual selection. In many animals, body size is an important trait because larger individuals enjoy greater fitness due to the ability to secure more mates and produce more offspring. Among males, this outcome is largely mediated by greater success in competition with rival males and (or) advantages in attractiveness to females. Here we tested the hypothesis that large male Marbled Salamanders (Ambystoma opacum (Gravenhorst, 1807)) mate with more females and produce more offspring than small males. In experimental breeding groups, we included males chosen specifically to represent a range of sizes. After gravid females mated and nested freely, we collected egg clutches and genotyped all adults and samples of hatchlings with highly variable microsatellite markers to assign paternity. Size had little effect on male mating and reproductive success. Breeding males were not bigger than nonbreeding males, mates of polyandrous females were not smaller than those of monogamous females, and there was no evidence for positive assortative mating by size. Although body size did not matter for male Marbled Salamanders, we documented considerable fitness variation and discuss alternative traits that could be undergoing sexual selection.

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