Differences in male and female traits (sexual dimorphism [SD]) are widespread in animals. Dimorphism in morphological characters evolves under the effect of environmental and genetic factors and is shaped by natural and sexual selection. In this study, intersexual differences in size and shape in common toad, Bufo bufo, populations in Turkey were investigated. For this, linear measurements of 27 body‐related morphometric characters in a sample of 140 individuals (70 males and 70 females) were compiled. The data were analyzed using univariate and multivariate statistical methods. The results show SD in body size with females having larger body size, a trait related with fecundity and thus probably under sexual selection. Body shape differences, which are associated with head width and dorsal head, are likely to prey size. Male‐biased differences observed in nasal characters and tympanum may also be associated with sexual selection (male–male competition). Our findings are consistent with previous studies of major of Anura and support a role for selection pressures acting differentially upon individuals from both sexes, resulting in the evolution of sexually dimorphic traits.
AbstractThe Bufo bufo species group includes four species distributed in the western Palearctic: B. bufo, B. eichwaldii, B. spinosus and B. verrucosissimus. Both B. bufo and B. verrucosissimus are known to occur in Turkey, but their range boundaries and the taxonomic status of B. verrucosissimus are still uncertain. In this study, we analyzed the variation in a set of morphological characters and in two mitochondrial and two nuclear DNA markers to address these questions. Phylogenetic analyses of sequence data support two main clades of common toads in Turkey, corresponding to B. bufo and B. verrucosissimus. The latter is subdivided into two allopatric subclades including populations along the Mediterranean and Black Sea coast, respectively. Discriminant analysis of morphological data showed separation among groups as defined by molecular analyses. We discuss these results and their implications for the evolutionary history of common toads in Turkey.
Sexual dimorphism, i.e., differences in morphology between sexes of a species caused by intersexual differences in the strength or direction of sexual or natural selection, is prevalent throughout the animal kingdom. Contrary to differences in body size, little is known about sexual shape dimorphism in anurans. Here we investigated intersexual shape differences in Bufo verrucosissimus (Pallas, 1814) by taking 27 linear measurements to characterize body morphology of 23 males and 23 females. Relative to their overall body size, males had longer limbs and larger eyes, while females displayed larger parotoid glands and had wider heads. We speculate that these intersexual differences may have arisen due to differences in natural and sexual selection regimes acting on males and females, especially during foraging, mate searching, or intrasexual competition.
In this study, we described age structure, body size, body mass and the relationships among these parameters for a population of P. caucasicus from Lake Borçka Karagöl, Artvin, Turkey. The mean SVL with standard error was 45.87 mm ± 0.55 (range: 39.98-50.28 mm) and the mean weight with standard error 8.81 g ± 0.39 (range: 6.10-11.47 g) in females whereas 48.16 mm ± 0.45 (range: 43.64-54.78 mm) and 11.32 ± 0.25 (range: 9.56-14.80 g) in males, respectively. We found a significant male-biased difference reflecting sexual dimorphism and statistically significant positive relationships between these variables. According to the results, the age ranged between 2-5 years in females and 2-6 years in males. The mean age distributions significantly differed between the sexes (females: 3.28 years ± 0.19; males: 3.94 years ± 0.20). The mean ages and maximal ages were found identical to the previously reported results from Turkey, but the mean ages were higher than in Georgian populations. Von Bertalanffy growth models demonstrated similar curves, and the growth rate was faster up to 3 years in both sexes. To conclude, this study was the first to determine age structure and growth patterns in Borçka Karagöl population and weight data for P. caucasicus was presented for the first time in the literature.
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