MORPHOLOGICAL TRAITS OF COMMON TOAD Bufo bufo ...

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104 Natura Montenegrina, 6/2007 Ventral side – abdominal part: 10a - round warts, 10b - oval warts, 10c - kidneylike warts; 11a – very protuberant warts, 11b – protuberant warts, 11c – drawn in warts; 12a – very marked thornlike ends of warts; 12b – medium marked thornlike ends of warts; 12c – weakly marked thornlike ends of warts; Trait Warts shape Condition a) round b) oval c) reniform a)very convex Warts convexity b) convex c) inverted Prominence of thornlike warts endings a)very prominent b)averagely prominent c)weakly prominent Table 1. Analysed qualitatie traits in Bufo bufo Statistical Analysis Programme package STATISTICA (version 5.0) has been used for statistical analysis of data. For morphometric characters basic parameters of descriptive statistics have been separately calculated by genders: medium value ( x ), error of medium value (SE), standard deviation (SD), minimal (min) and maximal (max) values traits as well as coeficient of variation (CV). Analysis of sexual dimorphism has been performed on basic data (untransformed measures for every property), as well as on standardized residuals on eight traits (L, Lpa, F, T, P, n, Lc, Ltc). Regression of every property on body length (L) and use of standardized residuals from such a regression provides for the elimination of the impact of body size. Comparison of differences between the genders on basic data and on standardised residuals has been performed by the use of Tukey Test for the samples of uneven size. For the establishment of the significance of differences in respect of morphometric characters between the genders analysis of variance (ANOVA) has been used. Absolute and relative frequences (%) of the conditions of qualitative traits have been established. Qualitative traits have been analysed also through the corresponding analyses.
105 Čađenović & Vukov: MORPHOLOGICAL TRAITS OF COMMON TOAD BUFO BUFO . . . RESULTS AND DISCUSSION Morphometric Characters Former data on values of morphometric characters of the species Bufo bufo are rather insufficient, or, some of them have been given only descriptively. That is why we have presented here the average values for a large number of characters that have not been previously analyzed and data about that do not exist in the literature. Basic parameters of morphometric characters descriptive statistics have been presented separately by sexes in the table 2. The smallest male of the sample of the population from Biogradsko Lake is 64.28, and the largest one 82.54 mm. The smallest female is 90.94 mm, and the largest 109.94 mm. Obtained values of body size of common toad from Biogradsko Lake are within the limits of the so far recorded values from other parts of areal of the species. (R a d o v a n o v i ć , 1951; A r n o l d and B u r t o n , 1978; Đ urović et al, 1979 etc). Sexual dimorphism has been analyzed in scope of population (localities) by application of Tukey test for samples of unequal size (“Unequal N HSD Tukey” test). This test has shown an expressed sexual dimorphism, where the females have higher average values of analyzed traits (Table 2). On basis of calculated parameters of descriptive statistics, separately by sexes and on basis of compared differences between the sexes, it has been established that the females have statistically higher values of all the characters, especially when the word is about L – body length, Lpa – length of front extremity, Lc – head length, Ltc – head width, Lg – length of salivary glands, weigth. With the population of Biogradsko Lake a great number of traits that have been demonstrating sexual dimorphism by the analysis of basic data where the size has been included, indicate the absence of sexual dimorphism for the largest number of characters when body size is excluded. The charactereistics which demonstrate the presence of sexual dimorphism also after the eliminating body size are T- length of tibiofibula and F – length of femur. Females are bigger than males in a large number of amphibian species (S h i n e , 1979; M i a u d et al., 1999; K h o n s u e et al.., 2001a, 2002b; M o n n e t and C h e r r y , 2002). That has been especially expressed with tailless amphibians in which females are bigger than males with 90% of species (S h i n e , 1979). This has also been established in this paper for studied population from Biogradsko Lake, as well as for the populations of the remaining part of the areal of distribution of this species (G i t t i n s et al., 1980; H e m e l a a r , 1988). The most common explanation of sexual dimorphism in body size is the advantge the females have in respect of eggs production (H a l l i d a y and V e r r e l l , 1986; C v e t k o v i ć et al., 2003). Namely, there is a positive correlation in many groups between body length and fecundity (C u m m i n s , 1986; B e r v e n , 1988; S i n s c h , 1998; G i b b o n s and M c C a r t h y , 1986). Assumption is that the selection, owing to a pointed correlation of body length
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MORPHOLOGICAL TRAITS OF COMMON TOAD Bufo bufo ...

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