Sexual Size Dimorphism Predicts the Frequency of Sexual Cannibalism Within and Among Species of Spiders

2008 ◽  
Vol 172 (3) ◽  
pp. 431-440 ◽  
Author(s):  
Shawn M. Wilder ◽  
Ann L. Rypstra
Keyword(s):  
Sexual Size Dimorphism ◽  
Sexual Cannibalism ◽  
Size Dimorphism

Mate choice and sexual size dimorphism, not personality, explain female aggression and sexual cannibalism in raft spiders

2016 ◽  
Vol 111 ◽  
pp. 49-55 ◽  
Author(s):  
Simona Kralj-Fišer ◽  
Klemen Čandek ◽  
Tjaša Lokovšek ◽  
Tatjana Čelik ◽  
Ren-Chung Cheng ◽  
...  
Keyword(s):  
Mate Choice ◽  
Sexual Size Dimorphism ◽  
Female Aggression ◽  
Sexual Cannibalism ◽  
Size Dimorphism

Sexual Size Dimorphism: Evolution and Perils of Extreme Phenotypes in Spiders

2020 ◽  
Vol 65 (1) ◽  
pp. 57-80 ◽  
Author(s):  
Matjaž Kuntner ◽  
Jonathan A. Coddington
Keyword(s):  
Equilibrium Model ◽  
Sexual Size Dimorphism ◽  
Size Variation ◽  
Sexual Cannibalism ◽  
Size Dimorphism ◽  
Terminal Investment ◽  
Dead End ◽  
Extreme Phenotypes ◽  
Context Specific ◽  
Female Gigantism

Sexual size dimorphism is one of the most striking animal traits, and among terrestrial animals, it is most extreme in certain spider lineages. The most extreme sexual size dimorphism (eSSD) is female biased. eSSD itself is probably an epiphenomenon of gendered evolutionary drivers whose strengths and directions are diverse. We demonstrate that eSSD spider clades are aberrant by sampling randomly across all spiders to establish overall averages for female (6.9 mm) and male (5.6 mm) size. At least 16 spider eSSD clades exist. We explore why the literature does not converge on an overall explanation for eSSD and propose an equilibrium model featuring clade- and context-specific drivers of gender size variation. eSSD affects other traits such as sexual cannibalism, genital damage, emasculation, and monogyny with terminal investment. Coevolution with these extreme sexual phenotypes is termed eSSD mating syndrome. Finally, as costs of female gigantism increase with size, eSSD may represent an evolutionary dead end.

Morphology and diet of two sympatric colubrid snakes, Chironius flavolineatus and Chironius quadricarinatus (Serpentes: Colubridae)

2008 ◽  
Vol 29 (2) ◽  
pp. 149-160 ◽  
Author(s):  
Otavio Augusto Vuolo Marques ◽  
Ronaldo Fernandes ◽  
Roberta Richard Pinto
Keyword(s):  
Foraging Behaviour ◽  
Sexual Size Dimorphism ◽  
Sympatric Species ◽  
Colour Pattern ◽  
Ontogenetic Variation ◽  
Brazilian Cerrado ◽  
Size Dimorphism ◽  
Snake Species ◽  
Dietary Ecology ◽  
Arboreal Habit

Abstract The morphometry and diet of two sympatric species of Chironius (C. flavolineatus and C. quadricarinatus) from Brazilian Cerrado are described. The two snake species differ in external morphology, as Chironius flavolineatus was the largest species (body, tail and eyes) whereas C. quadricarinatus the heaviest. Each species also showed marked sexual size dimorphism. In terms of dietary ecology, both species feed exclusively on frogs with a heavy preference for hylids and may have tendency to eat small items, as noticed in other colubrine species. These two snake species showed a brownish colour pattern and exhibited no ontogenetic variation, suggesting that juveniles and adults use similar substrates. Chironius flavolineatus and C. quadricarinatus present a semi-arboreal habit, with active foraging behaviour, feeding in the ground most of time. Chironius flavolineatus uses higher vegetation for resting and, based on morphological results, seems to be more arboreal than C. quadricarinatus.

Latitudinal clines in sexual selection, sexual size dimorphism, and sex‐specific genetic dispersal during a poleward range expansion

2021 ◽  
Author(s):  
Rachael Y. Dudaniec ◽  
Alexander R. Carey ◽  
Erik I. Svensson ◽  
Bengt Hansson ◽  
Chuan Ji Yong ◽  
...  
Keyword(s):  
Sexual Selection ◽  
Range Expansion ◽  
Sexual Size Dimorphism ◽  
Size Dimorphism ◽  
Latitudinal Clines

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.

Genetic analysis of sexual size dimorphism in Markhoz goat

2021 ◽  
Vol 53 (1) ◽  
Author(s):  
Hasan Baneh ◽  
Mostafa Ghaderi-Zefrehei ◽  
Raana Pouryaei ◽  
Ajoy Mandal
Keyword(s):  
Genetic Analysis ◽  
Sexual Size Dimorphism ◽  
Size Dimorphism
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