Sexual size and shape dimorphism in Turkish common toads (Bufo bufo Linnaeus 1758)

Abstract

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.

Ladies in armor: A micro‐computed tomographic study of skin calcification in European toads (genus Bufo)

“…Also, body size could associate with sexual dimorphism in skin thickness (VanBuren et al, 2019). We found that the level of head skin calcification was positively related to skull size which coincided with a marked, female biased sexual size dimorphism (Arntzen, 1999; Lüscher et al, 2001; Čađenović et al, 2013; Ivanović et al, 2022; Dursun et al, 2022). Yet, the calcification level of the head skin and the parotoids cannot be solely explained by size.…”

“…We expected higher level of skin calcification in B. spinosus than in B. bufo. As there is a pronounced sexual dimorphism in the skull size of both species B. bufo and B. spinosus (Arntzen, 1999;Lüscher et al, 2001;Čađenovi c et al, 2013;Ivanovi c et al, 2022;Dursun et al, 2022), we expected that sexual dimorphism would be confirmed for the level of calcification as well.…”

“…The species may also differ in the amount of keratinization in epidermis (Arntzen et al, 2013; Čađenović et al, 2013). Both species show a significant sexual size dimorphism with females being larger than males (Arntzen, 1999; Lüscher et al, 2001; Dursun et al, 2022; Ivanović et al, 2022).…”

Sexual Dimorphism in the Chinese Endemic Species Hynobius maoershanensis (Urodela: Hynobiidae)

“…Sexual dimorphism in the body shape of amphibians can be divided into three types: (a) female adults are larger than male adults, (b) male adults are larger than female adults and (c) there is no difference in the size of male and female adults [5,12]. The first of these is the most prevalent type and favours improvement in reproductive output [12,17,41]. In previous studies, urodelans, such as Paramesotriton guangxiensis [42], Paramesotriton fuzhongensis [42] and Cynops orientalis [43], and anurans, such as Hyla eximia [44], Charadrahyla sakbah [45], Crossodactylus schmidti [46] and Microhyla beilunensis [47], among others, have been shown to belong to the first type, i.e., the female adult is larger than the male adult.…”

“…Sexual dimorphism in body size is often associated with the reproductive behaviours of animals [14,15]. In amphibians, the larger body size in females may be related to the ability to produce more offspring [16,17], whereas the larger size in males may aid in finding mates or caring for offspring [8,14]. For example, in male-biased SSD poison frogs, males often provide more care than females, Animals 2022, 12, 1712 2 of 10 such as egg attendance and tadpole transport [14].…”