Growth, maturity, and sexual dimorphism in the wood turtle, Clemmys insculpta

1990 ◽  
Vol 68 (4) ◽  
pp. 672-677 ◽  
Author(s):  
Jeffrey E. Lovich ◽  
Carl H. Ernst ◽  
John F. McBreen
Keyword(s):  
Body Size ◽  
Sexual Dimorphism ◽  
Carapace Length ◽  
Sexual Size Dimorphism ◽  
Von Bertalanffy ◽  
Size Dimorphism ◽  
Adult Females ◽  
Body Sizes ◽  
Von Bertalanffy Growth Model ◽  
Wood Turtle

Growth in the wood turtle (Clemmys insculpta) is described using the von Bertalanffy growth model and nonlinear regression. Growth in both sexes is similar until about 160 mm plastron length. Males grew at a faster rate after this size. Males appear to mature at a larger size and later age than females, although age-specific body size is highly variable. Sexual size dimorphism, in carapace length, is pronounced, with males attaining mean body sizes significantly larger (1.07–1.10 times) than those of adult females. Plastron length is an inappropriate measure of sexual size dimorphism because of the development of plastral concavity in males. Females tend to predominate in samples, possibly owing to differential maturity of the sexes. The direction of sexual size dimorphism may be maintained by intrasexual competition among males for access to females. Data for several adults captured at intervals of from 9 to 20 years support the concept of indeterminate growth.

scholarly journals A skeletochronological estimate of age and growth in a large riparian frog from Madagascar (Anura, Mantellidae, Mantidactylus)

Herpetozoa ◽  
2019 ◽  
Vol 32 ◽  
pp. 39-44 ◽  
Author(s):  
Fabio M. Guarino ◽  
Angelica Crottini ◽  
Marcello Mezzasalma ◽  
Jasmin E. Randrianirina ◽  
Franco Andreone
Keyword(s):  
Growth Rate ◽  
Body Size ◽  
Sexual Size Dimorphism ◽  
The Body ◽  
Age And Growth ◽  
Growth Trajectories ◽  
Growth Coefficient ◽  
Size Dimorphism ◽  
Adult Females ◽  
Similar Growth

We characterized the body size (as snout-vent length), age, sexual size dimorphism, and growth rate in a population of one of the larger riparian frog from Madagascar (Mantidactylusgrandidieri) from a rainforest patch close to Vevembe, SE Madagascar. We identified a significant female-biased sexual size dimorphism. Age was estimated using phalangeal skeletochronology and was significantly higher in females than in males. Modal age class turned out to be 4 years in both sexes but a large percentage of adult females (75%) fell in the 5–6 years-old classes, while no male exceeded 4 years. We here report M.grandidieri as a medium-long-lived anuran species. Von Bertalanffy’s model showed similar growth trajectories between the sexes although the growth coefficient in females (k = 0.335) was slightly but not significantly higher than in males (k = 0.329).

Interpopulational variation in sexual dimorphism, reproductive output, and parasitism of Liophis miliaris (Colubridae) in the Atlantic forest of Brazil

2006 ◽  
Vol 27 (1) ◽  
pp. 37-46 ◽  
Author(s):  
Lígia Pizzatto ◽  
Otavio Marques
Keyword(s):  
Body Size ◽  
Sexual Dimorphism ◽  
Atlantic Forest ◽  
Reproductive Output ◽  
Sexual Size Dimorphism ◽  
The Other ◽  
Female Body Size ◽  
Body Sizes ◽  
Northern Atlantic ◽  
Males And Females

AbstractSexual maturity, sexual dimorphism, reproductive output, and parasitism of the colubrid snake Liophis miliaris were compared among populations inhabiting four regions of Brazil: (1) northern coastal Atlantic forest, (2) southern coastal Atlantic forest, (3) northern inland Atlantic forest (4) southern inland Atlantic forest. Females delayed maturity and attained larger body sizes than males in all regions. Males and females from northern Atlantic forest were smaller and attained maturity with a smaller body size than males of other regions. The sexual size dimorphism index ranged from 0.19 to 0.23 and was lowest in the northern Atlantic forest. There was no sexual dimorphism in head length in any of the populations studied. Clutch size was similar in all populations and increased with maternal body size. The reproductive frequency was lower in the northern coastal Atlantic forest and in contrast to the other regions, tended to increase with female body size. The nematoda Ophidiascaris sp. and cystacanths of Oligacanthorynchus spira (Acanthocephala) occurred equally in both sexes. Fewer snakes from the northern coastal Atlantic forest were infested by parasites compared to the other regions and parasitism apparently did not influence reproduction.

scholarly journals Size- and sex-specific predation on dung flies by amphibian and arthropod predators – size match matters

2019 ◽  
Author(s):  
Wolf U. Blanckenhorn ◽  
Gabriele Cozzi ◽  
Gregory Jäggli ◽  
Juan Pablo Busso
Keyword(s):  
Body Size ◽  
Sexual Size Dimorphism ◽  
Rana Temporaria ◽  
Large Body ◽  
Mechanistic Study ◽  
Mating Activity ◽  
Size Dimorphism ◽  
Arthropod Predators ◽  
Body Sizes ◽  
Predation Rates

Because predator-prey interactions in nature are multifarious, linking phenomenological predation rates to the underlying behavioural or ecological mechanisms is challenging. Size- and sex-specific predation has been implicated as a major selective force keeping animals small, affecting the evolution of body size and sexual size dimorphism. We experimentally assessed predation by various amphibian (frogs and toads) and arthropod predators (bugs, flies, spiders) on three species of dung flies with similar ecology but contrasting body sizes, sexual size dimorphism and coloration. Predators were offered a size range of flies in single- or mixed-sex groups. As expected based on optimal foraging theory, some anurans (e.g. Bufo bufo) selected larger prey, thus selecting against large body size of the flies, while others (Bombina variagata and Rana esculenta) showed no such pattern. Small juvenile Rana temporaria metamorphs, in contrast, preferred small flies, as did all arthropod predators, a pattern that can be explained by larger prey being better at escaping. The more mobile males were not eaten more frequently or faster than the cryptic females, even when conspicuously colored. Predation rates on flies in mixed groups permitting mating activity were not higher, contrary to expectation, nor was predation generally sex-specific. We conclude that the size-selectivity of predators, and hence the viability selection pattern exerted on their prey, depends foremost on the relative body sizes of the two in a continuous fashion. Sex-specific predation by single predators appears to contribute little to sexual dimorphism. Therefore, the mechanistic study of predation requires integration of both the predator’s and the prey’s perspectives, and phenomenological field studies of predation remain indispensable.

Pythons in the pergola: the ecology of 'nuisance' carpet pythons (Morelia spilota) from suburban habitats in south-eastern Queensland

2001 ◽  
Vol 28 (6) ◽  
pp. 573 ◽  
Author(s):  
S. Fearn ◽  
B. Robinson ◽  
J. Sambono ◽  
R. Shine
Keyword(s):  
Body Size ◽  
Food Habits ◽  
Sexual Size Dimorphism ◽  
Activity Patterns ◽  
Dietary Composition ◽  
Seasonal Activity ◽  
Size Dimorphism ◽  
South Eastern ◽  
Two Cities ◽  
Body Sizes

Carpet pythons (Morelia spilota) are large (to >4 m, 11 kg) non-venomous snakes that are widely distributed across mainland Australia. In many parts of their range, viable populations persist even in highly disturbed urban and suburban habitats. Over a six-year period, we collected 258 ‘nuisance’ pythons from two cities (Brisbane and Ipswich) in south-eastern Queensland. Most of these snakes were reported by members of the general public, often after the snakes had consumed domestic pets or cage-birds. We provide data on seasonal activity patterns, body sizes, sexual size dimorphism, reproduction and food habits of these snakes. Snakes were active and fed year-round, primarily on domestic and commensal birds and mammals. Dietary composition shifted with body size: one small snake consumed a lizard, intermediate-sized snakes took mostly mice, rats and parrots, and large snakes fed on larger items such as cats, brushtail possums and poultry. Adult male pythons engaged in combat bouts during the breeding season, and (perhaps as an adaptation to enhance success in such bouts) grew larger and were more heavy-bodied than conspecific females.

Sexual dimorphism in a freshwater atyid shrimp (Decapoda: Caridea) with direct development: a geometric morphometrics approach

Zootaxa ◽  
2016 ◽  
Vol 4196 (1) ◽  
pp. 120 ◽  
Author(s):  
DANIELA ELIANA SGANGA ◽  
LUCAS RAUL FERNANDEZ PIANA ◽  
LAURA SUSANA LÓPEZ GRECO
Keyword(s):  
Sexual Dimorphism ◽  
Geometric Morphometrics ◽  
Mating System ◽  
Abdominal Segment ◽  
Sexual Size Dimorphism ◽  
Centroid Size ◽  
Caridean Shrimp ◽  
Size Dimorphism ◽  
Adult Females ◽  
Ornamental Species

Neocaridina davidi is a caridean shrimp that has gained popularity in recent years as an ornamental species. Using geometric morphometrics, we investigated sexual dimorphism in carapace and second abdominal segment shape of N. davidi. Adult females displayed a more elongated carapace and a longer rostrum than males. However, male carapace shape was similar to that of juvenile females. The second abdominal pleura was more elongated and wider in adult females than in males. Significant differences were found in centroid size for the carapace and the second abdominal segment between sexes, which is consistent with sexual size dimorphism. These results support the hypothesis of a “pure search” mating system in N. davidi, where small males search actively for receptive females, and after insemination they continue searching. 

scholarly journals Sexual Size Dimorphism in Stone Marten (MARTES Foina, Erxl. 1777) from Sarnena Sredna Gora Mts (BULGARIA)

2019 ◽  
Vol 17 (4) ◽  
pp. 318-322
Author(s):  
S. Peeva
Keyword(s):  
Body Size ◽  
Sexual Dimorphism ◽  
Sexual Size Dimorphism ◽  
Tail Length ◽  
Stone Marten ◽  
Martes Foina ◽  
Size Dimorphism

Sexual dimorphism in body size measurements of 65 stone martens was investigated in winter periods (10.12.- 01.03) 2013 to 2017. There was found sexual dimorphism in body size of Stone Marten from Central Bulgaria: males were larger than females. The tail length (with or without hairs) did not depend on sex. The sexual dimorphism in the most variable linear parameters of the species varied from 2.76% to 10.63%. Male stone martens were 23.37% heavier than females.

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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