scholarly journals SEXUAL SIZE DIMORPHISM AND EGG-SIZE ALLOMETRY IN BIRDS

Evolution ◽  
1994 ◽  
Vol 48 (3) ◽  
pp. 671-678 ◽  
Author(s):  
Patrick J. Weatherhead ◽  
Kevin L. Teather
2012 ◽  
Vol 58 (2) ◽  
pp. 236-243 ◽  
Author(s):  
Laigao Luo ◽  
Yilian Wu ◽  
Zhuyuan Zhang ◽  
Xuefeng Xu

Abstract Sexual size dimorphism (SSD) has long attracted the attention of biologists, and life-history variation is thought to play an important role in the evolution of SSD. Here we quantified SSD and female reproductive traits to identify potential associations between SSD and female reproduction in the white-striped grass lizard Takydromus wolteri. In a population from Chuzhou, China, the largest male and female were 53.0 mm and 57.5 mm in snout-vent length (SVL), respectively. Females were larger in SVL and abdomen length, whereas males were larger in head size and tail length. Females produced up to five clutches of eggs during the breeding season, with large females producing more clutches and more eggs per clutch than small ones. As a result, large females had a higher annual fecundity and reproductive output. Egg size was positively correlated with maternal SVL in the first clutch, but not in subsequent clutches. These results suggest that T. wolteri is a species with female-biased SSD, and that fecundity selection, in which large females have higher fecundity due to their higher capacity for laying eggs, is likely correlated with the evolution of SSD in this species [Current Zoology 58 (2): 236–243, 2012].


Evolution ◽  
1994 ◽  
Vol 48 (3) ◽  
pp. 671 ◽  
Author(s):  
Patrick J. Weatherhead ◽  
Kevin L. Teather

2006 ◽  
Vol 2 (2) ◽  
pp. 206-208 ◽  
Author(s):  
Terje Lislevand ◽  
Gavin H Thomas

In bird species where males incubate but are smaller than females, egg size may be constrained by male body size, and hence ability to incubate the eggs. Using data from 71 such shorebird species, we show that egg size decreases as the degree of female-biased sexual size dimorphism increases, after controlling for female body mass. Relative egg size was not related to mean clutch size. However, when controlling for mating system, the relationship between female-biased sexual size dimorphism and relative egg size was only significant in polyandrous species. The relatively small eggs of socially polyandrous shorebirds have previously been explained as an energy-saving strategy associated with the production of multiple clutches. Our findings suggest that egg size evolution is better explained by male incubation limitation in these birds.


2008 ◽  
Vol 29 (2) ◽  
pp. 149-160 ◽  
Author(s):  
Otavio Augusto Vuolo Marques ◽  
Ronaldo Fernandes ◽  
Roberta Richard Pinto

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.


Author(s):  
Rachael Y. Dudaniec ◽  
Alexander R. Carey ◽  
Erik I. Svensson ◽  
Bengt Hansson ◽  
Chuan Ji Yong ◽  
...  

Biologia ◽  
2015 ◽  
Vol 70 (9) ◽  
pp. 1228-1233 ◽  
Author(s):  
Ehsan Sanaei ◽  
Marjan Seiedy ◽  
Farzaneh Momtazi

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.


2021 ◽  
Vol 53 (1) ◽  
Author(s):  
Hasan Baneh ◽  
Mostafa Ghaderi-Zefrehei ◽  
Raana Pouryaei ◽  
Ajoy Mandal

2021 ◽  
Vol 34 (4) ◽  
pp. 594-603
Author(s):  
Gergely Katona ◽  
Balázs Vági ◽  
Zsolt Végvári ◽  
András Liker ◽  
Robert P. Freckleton ◽  
...  

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