Growth Rates, Maturation and Sexual Size Dimorphism in a Population of Grass Snakes, Natrix natrix, in Southern Sweden

Oikos ◽  
1983 ◽  
Vol 40 (2) ◽  
pp. 277 ◽  
Author(s):  
Thomas Madsen
Keyword(s):  
Growth Rates ◽  
Sexual Size Dimorphism ◽  
Southern Sweden ◽  
Size Dimorphism ◽  
Natrix Natrix

Environmentally determined juvenile growth rates dictate the degree of sexual size dimorphism in the Sardinian brook newt

2014 ◽  
Vol 29 (1) ◽  
pp. 169-184 ◽  
Author(s):  
Claudio Angelini ◽  
Giuseppe Sotgiu ◽  
Giulia Tessa ◽  
Jon Bielby ◽  
Stefano Doglio ◽  
...  
Keyword(s):  
Growth Rates ◽  
Sexual Size Dimorphism ◽  
Juvenile Growth ◽  
Size Dimorphism

Sexual size dimorphism of walleye (Stizostedion vitreum vitreum)

2003 ◽  
Vol 60 (11) ◽  
pp. 1345-1352 ◽  
Author(s):  
Bryan A Henderson ◽  
Nicholas Collins ◽  
George E Morgan ◽  
Andre Vaillancourt
Keyword(s):  
Growth Rates ◽  
Sexual Size Dimorphism ◽  
Growth Efficiency ◽  
Stizostedion Vitreum ◽  
Relative Importance ◽  
Male Fitness ◽  
Size Dimorphism ◽  
Before And After ◽  
Males And Females ◽  
Epaxial Muscle

Sexual size dimorphism of walleye (Stizostedion vitreum vitreum) is achieved by females having higher growth rates than males before and after maturation, resulting in females with greater asymptotic sizes. Mercury (Hg) concentrations in epaxial muscle by age and weight for 31 populations of walleye were used to evaluate the relative importance of differences in consumption and activity in generating sexual size dimorphism. Growth efficiency by sex, age, and maturity is estimated by a ratio of annual increments in weight (g) to annual increments of Hg (mg), using the pooled changes in weight and Hg loadings of males and females from all lakes. The higher growth rates of females arise from greater consumption and higher growth efficiency. Growth efficiency of both sexes is similar before maturity, but the growth efficiency of mature males is substantially lower than that of either immature males or mature females. We propose that the inferior growth efficiency of males is a function of the greater activity of males, particularly during the spawning season when scramble competition for fertilization is likely to produce substantial increases in male fitness as a result of increased efforts to find and spawn with females.

Influence of forced renesting and hand-rearing on growth of young captive American Kestrels

1982 ◽  
Vol 60 (1) ◽  
pp. 89-96 ◽  
Author(s):  
David M. Bird ◽  
Paul C. Laguë
Keyword(s):  
Growth Rates ◽  
Sexual Size Dimorphism ◽  
Falco Sparverius ◽  
Tarsus Length ◽  
Size Dimorphism ◽  
American Kestrels ◽  
Body Weights ◽  
Catch Up

During 1974 to 1977, 78 pairs of captive American Kestrels (Falco sparverius) were forced to renest and the hatchlings from the artificially incubated first clutches were hand-reared to fledging age. Sexual size dimorphism, i.e., heavier females, became evident at some undetermined point between the 6th and 12th day of growth. Overall, hand-reared kestrels exhibited significantly slower growth rates and smaller body weights on the 24th day than did parent-raised birds. They did tend to "catch up" to the parent-raised ones, as there were no significant differences later with respect to juvenile and adult weights. Antebrachium and manus length, tarsus length and diameter, and skull width were significantly smaller in hand-reared kestrels.

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.

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