Sexual size dimorphism in the American rubyspot: male body size predicts male competition and mating success

2007 ◽  
Vol 73 (6) ◽  
pp. 987-997 ◽  
Author(s):  
M.A. Serrano-Meneses ◽  
A. Córdoba-Aguilar ◽  
V. Méndez ◽  
S.J. Layen ◽  
T. Székely
Keyword(s):  
Body Size ◽  
Mating Success ◽  
Sexual Size Dimorphism ◽  
Male Competition ◽  
Male Body ◽  
Size Dimorphism ◽  
Male Body Size

Effects of body size and mass on running speed of male yellow-pine chipmunks (Tamias amoenus)

2002 ◽  
Vol 80 (9) ◽  
pp. 1584-1587 ◽  
Author(s):  
Albrecht I Schulte-Hostedde ◽  
John S Millar
Keyword(s):  
Body Size ◽  
Mating Success ◽  
Sexual Size Dimorphism ◽  
Small Male ◽  
Male Body ◽  
Running Speed ◽  
Size Dimorphism ◽  
Male Body Size ◽  
Tamias Amoenus ◽  
Yellow Pine

Male-biased sexual size dimorphism in mammals is usually attributed to the success of large males in intrasexual combat for mates. However, mating success may be determined by contests that are not combative. In the mating chase of the yellow-pine chipmunk (Tamias amoenus), a mammalian species with female-biased sexual size dimorphism, fast males may have an advantage in acquiring matings with estrous females. However, the effects of intraspecific variation in body size on running speed are not obvious; heavy individuals may run more slowly than light individuals because excess mass can be a hindrance to locomotion, but individuals that are structurally large may run faster than small individuals because of longer stride length. We examined the effects of both body mass and structural size on running speed in male yellow-pine chipmunks using manipulated runs in which male chipmunks were chased over a known distance. Structurally large male chipmunks had faster running speeds than small males, potentially giving large males an advantage when chasing estrous females. However, small male chipmunks are known to be aggressively dominant over large males. This leads to a potential trade-off in male body size between two behavioural components of mating success (running speed and dominance) that may constrain the evolution of male body size, ultimately leading to female-biased sexual size dimorphism.

scholarly journals Sneaker Males Affect Fighter Male Body Size and Sexual Size Dimorphism in Salmon

2016 ◽  
Vol 188 (2) ◽  
pp. 264-271 ◽  
Author(s):  
Laura K. Weir ◽  
Holly K. Kindsvater ◽  
Kyle A. Young ◽  
John D. Reynolds
Keyword(s):  
Body Size ◽  
Sexual Size Dimorphism ◽  
Male Body ◽  
Size Dimorphism ◽  
Male Body Size

Geographic variation in body size and sexual size dimorphism of North American Ratsnakes (Pantherophis spp. s.l.)

2018 ◽  
Vol 96 (11) ◽  
pp. 1196-1202 ◽  
Author(s):  
Brett A. DeGregorio ◽  
Gabriel Blouin-Demers ◽  
Gerardo L.F. Carfagno ◽  
J. Whitfield Gibbons ◽  
Stephen J. Mullin ◽  
...  
Keyword(s):  
Body Size ◽  
Large Scale ◽  
Sexual Size Dimorphism ◽  
Size Variation ◽  
Sexually Dimorphic ◽  
Male Body ◽  
Complex Species ◽  
Size Dimorphism ◽  
Body Size Variation ◽  
Female Body Size

Because body size affects nearly all facets of an organism’s life history, ecologists have long been interested in large-scale patterns of body-size variation, as well as why those large-scale patterns often differ between sexes. We explored body-size variation across the range of the sexually dimorphic Ratsnake complex (species of the genus Pantherophis Fitzinger, 1843 s.l.; formerly Elaphe obsoleta (Say in James, 1823)) in North America. We specifically explored whether variation in body size followed latitudinal patterns or varied with climatic variables. We found that body size did not conform to a climatic or latitudinal gradient, but instead, some of the populations with the largest snakes occurred near the core of the geographic range and some with the smallest occurred near the northern, western, and southern peripheries of the range. Males averaged 14% larger than females, although the degree of sexual size dimorphism varied between populations (range: 2%–25%). There was a weak trend for male body size to change in relation to temperature, whereas female body size did not. Our results indicate that relationships between climate and an ectotherm’s body size are more complicated than linear latitudinal clines and likely differ for males and females.

scholarly journals Sexual selection on size and shape in Japanese beetles (Popillia japonica)

2020 ◽  
Vol 31 (4) ◽  
pp. 1073-1083 ◽  
Author(s):  
Clint D Kelly
Keyword(s):  
Sexual Selection ◽  
Body Size ◽  
Mating Success ◽  
Insect Pest ◽  
Popillia Japonica ◽  
Female Size ◽  
Male Body ◽  
Japanese Beetle ◽  
Size Dimorphism ◽  
Selection For

Abstract The mobility hypothesis argues that species in which males compete for mates in scrambles often exhibit female-biased size dimorphism because smaller male body size should increase male mobility and success in searching for mates. Sexual dimorphism can be further exaggerated if fecundity or sexual selection concurrently selects for larger female size. Scramble competition can select for trait characteristics that optimize locomotion; for example, long and slender wings should be favored if aerial speed is important to mating success. I tested these predictions in the scrambling Japanese beetle (Popillia japonica), a female-biased size dimorphic insect pest that is invasive to North America. Multivariate selection analyses support the prediction that smaller body size and larger wings in males benefit their mating success. My analyses also revealed significant selection for larger wings in females but, contrary to prediction, direct sexual selection favors smaller body size in females. These results support the mobility hypothesis and partially explain the evolution of female-biased size dimorphism in this species. Sexual selection favored rounder bodies in females and more tapered bodies in males, whereas, in both sexes, the effect of wing shape appears less important to fitness than wing size.

scholarly journals Disruptive sexual selection on male body size in the polyphenic black scavenger fly Sepsis thoracica

2018 ◽  
Vol 29 (3) ◽  
pp. 769-777 ◽  
Author(s):  
Juan Pablo Busso ◽  
Wolf U Blanckenhorn
Keyword(s):  
Sexual Selection ◽  
Body Size ◽  
Reproductive Success ◽  
Mating Success ◽  
Directional Selection ◽  
Disruptive Selection ◽  
Simultaneous Occurrence ◽  
Male Body ◽  
Male Body Size ◽  
Starting Point

Abstract Sexual selection has 2 main components, female preference and male–male competition, which can lead males to adopt alternative reproductive tactics to optimize their reproductive success. Two traits that significantly influence reproductive success are body size and coloration, as they can facilitate access to females through male contests or as female attractors. We investigated whether, and if so which mechanism of sexual selection contributes to the maintenance, and possibly even the establishment, of 2 almost discrete male morphs in the polyphenic black scavenger fly Sepsis thoracica (Diptera: Sepsidae): small and black, or large and amber. We performed 2 complementary laboratory experiments to evaluate the mating success of the different male morphs and the behaviors (of both males and females) presumably mediating their mating success. We found evidence for intraspecific disruptive sexual selection on male body size that is mediated by male–male interactions, and significant positive directional selection on body size that interacted with (directional) selection on coloration, likely contributing to the origin and/or maintenance of the threshold relationship between the 2 traits in this species. The simultaneous occurrence of disruptive selection and polyphenism in S. thoracica supports the role of sexual selection in the intraspecific diversification of coupled traits (here body size and coloration), which could be a speciation starting point.

Is bigger better? Male body size affects wing-borne courtship signals and mating success in the olive fruit fly,Bactrocera oleae(Diptera: Tephritidae)

2015 ◽  
Vol 23 (6) ◽  
pp. 869-880 ◽  
Author(s):  
Giovanni Benelli ◽  
Elisa Donati ◽  
Donato Romano ◽  
Giacomo Ragni ◽  
Gabriella Bonsignori ◽  
...  
Keyword(s):  
Body Size ◽  
Mating Success ◽  
Fruit Fly ◽  
Bactrocera Oleae ◽  
Olive Fruit Fly ◽  
Male Body ◽  
Olive Fruit ◽  
Male Body Size ◽  
Courtship Signals
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