Body Size, Size Variation, and Sexual Size Dimorphism in Early Homo

2012 ◽  
Vol 53 (S6) ◽  
pp. S409-S423 ◽  
Author(s):  
J. Michael Plavcan
Keyword(s):  
Body Size ◽  
Sexual Size Dimorphism ◽  
Size Variation ◽  
Size Dimorphism ◽  
Early Homo

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 Body size variation and sexual size dimorphism across climatic gradients in the widespread treefrogScinax fuscovarius(Anura, Hylidae)

2017 ◽  
Vol 43 (1) ◽  
pp. 35-45 ◽  
Author(s):  
Javier Goldberg ◽  
Darío Cardozo ◽  
Francisco Brusquetti ◽  
Diego Bueno Villafañe ◽  
Andrea Caballero Gini ◽  
...  
Keyword(s):  
Body Size ◽  
Sexual Size Dimorphism ◽  
Size Variation ◽  
Size Dimorphism ◽  
Body Size Variation

scholarly journals Modeling sexual differences of body size variation in ground beetles in geographical gradient (The case study in Pterostichus oblongpunctatus Fabricius, 1787)

2020 ◽  
Vol 13 (3) ◽  
pp. 149-161
Author(s):  
Raisa A Sukhodolskaya ◽  
Anatoly A Saveliev ◽  
Nadezhda L Ukhova ◽  
Iraida G Vorobyova ◽  
Igor A Solodovnikov ◽  
...  
Keyword(s):  
Body Size ◽  
Sexual Size Dimorphism ◽  
Ground Beetle ◽  
Geographical Location ◽  
Size Variation ◽  
Ground Beetles ◽  
Mean Values ◽  
Size Dimorphism ◽  
Body Size Variation

Fleshing out the mechanisms of Bergmann rule, we found saw-tooth pattern in body size variation in ground beetle Pterostichus oblongopunctatus. We sampled beetles in 2010 – 2018 at the forest undisturbed plots on the broad territory in Russia and Belarus. Investigating regions covered territory, extending to 3 degrees latitude and 31 degrees longitude. We measured six traits in every of 3294 caught individuals. ANOVA showed that geographical location and sex affected significantly body size of the species studied. Mean values of each trait changed significantly from one studied region to another in females and males as well. Sexual size dimorphism in species was female-biased. We performed models in R to estimate the steepness of body size variation in both sexes. In overwhelming majority of cases that parameter was equal in both sexes. So the hypothesis, that male′s variation is steeper in latitude gradient was not confirmed.

Body size, sexual size dimorphism, and Rensch's rule in adult hydropsychid caddisflies (Trichoptera: Hydropsychidae)

2003 ◽  
Vol 81 (12) ◽  
pp. 1956-1964 ◽  
Author(s):  
Jason E Jannot ◽  
Billie L Kerans
Keyword(s):  
Body Size ◽  
Sexual Size Dimorphism ◽  
Interspecific Interactions ◽  
Size Variation ◽  
Rensch’S Rule ◽  
Size Dimorphism ◽  
Selective Pressures ◽  
Rensch's Rule ◽  
Phylogenetic Inertia ◽  
Males And Females

Body size influences most biological processes from metabolic rates to the outcome of interspecific interactions. Within a species, sexual size dimorphism (SSD) reflects either differential selection on body size of males and females or phylogenetic inertia. Among taxa, SSD should decrease as body size increases when females are the larger sex — a pattern known as Rensch's rule. We examined body size, SSD, and Rensch's rule among 29 species of adult hydropsychid caddisflies (Trichoptera: Hydropsychidae) and 12 closely related caddisfly species. Females were almost always larger than males in all species examined. Body size variation among genera was greater than variance among species. In contrast, the greatest variance in SSD was among species within a genus. Contrary to Rensch's rule, the degree of SSD did not change as body size increased among genera. Observed body size patterns suggest that hydropsychid caddisfly species within a genus may be subjected to similar selective pressures during the larval stage, but this issue remains to be investigated. In addition, our data suggest that hydropsychids may violate Rensch's rule, a pattern not often reported. Our data provide a basis for proposing and testing hypotheses about the ecology and evolution of hydropsychid caddisflies.

scholarly journals Modeling Sexual Differences of Body Size Variation in Ground Beetles in Geographical Gradient (The Case Study in Pterostichus oblongopunctatus Fabricius, 1787)

2020 ◽  
Author(s):  
Raisa Sukhodolskaya ◽  
Anatoliy Saveliev ◽  
Nadezhda Ukhova ◽  
Iraida Vorobyova ◽  
Igor Solodovnikov ◽  
...  
Keyword(s):  
Body Size ◽  
Sexual Size Dimorphism ◽  
Ground Beetle ◽  
Size Variation ◽  
Ground Beetles ◽  
Mean Values ◽  
Size Dimorphism ◽  
Body Size Variation ◽  
Pterostichus Oblongopunctatus

Concretizing the mechanisms of Bergmann rule, we found saw-tooth pattern in body size variation in ground beetle Pterostichus oblongopunctatus. We sampled beetles in 2010 – 2018 at the forest undisturbed plots on the broad territory in Russia. Investigating regions covered territory, extending to 3 degrees latitude and 19 degrees longitude. We measured six traits in every of 3294 caught individual. ANOVA showed that latitude, and sex affected significantly body size of the species studied. Mean values of each trait changed significantly from one studied region to another in females and males as well. Sexual size dimorphism in species was female-biased. We performed models in R to estimate the steepness of body size variation in both sexes. In overwhelming majority of cases that parameter was equal in both sexes. So the hypothesis, that male′s variation is steeper in latitude gradient was not confirmed.

scholarly journals A uni- and multivariate analysis approach to reveal sexual size dimorphism in Iranian populations of Hypera postica (Coleoptera: Curculionidae)

Biologia ◽  
2015 ◽  
Vol 70 (9) ◽  
pp. 1228-1233 ◽  
Author(s):  
Ehsan Sanaei ◽  
Marjan Seiedy ◽  
Farzaneh Momtazi
Keyword(s):  
Body Size ◽  
Sexual Size Dimorphism ◽  
Egg Laying ◽  
Morphological Divergence ◽  
High Fecundity ◽  
Hypera Postica ◽  
Size Dimorphism ◽  
Female Body Size ◽  
Divergence Pattern ◽  
Iranian Populations

Abstract Body size dimorphism between genders is a commonly observed phenomenon in insects, usually manifested in larger female body size. Sexual Size Dimorphism (SSD) varies from species to species, the degree and direction influenced by certain evolutionary pressures. Intraspecific variation in SSD may also occur between populations. The Hypera postica (Gyllenhal, 1813) is a well-known alfalfa plant pest that shows a degree of morphological divergence in its populations. The female alfalfa weevils are very fecund and have a larger body size compared to males. To improve our knowledge on magnitude and direction of SSD in alfalfa weevil, we studied 200 specimens of H. postica from four Iranian populations (Karaj1, Karaj2, Tuyserkan and Jovein). 10 morphological variables from three external anatomic parts (pronotum, elytra and rostrum) and 45 ratio characters were statistically analyzed in order to determine the amount of SSD in Iranian populations. In addition we investigated for morphological divergence pattern in mentioned populations. The results of this study show that a low degree of morphological divergence occurs in Iranian populations. Measured variables indicate that the SSD pattern of H. postica is compatible with the Rensch’s rule, and is related to high fecundity of females and a lack of strong sexual selection. Also it is mentioned that the larger rostrum in females may correspond to its unique role in egg laying.

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