Variability in ventral spot patterns of frogs of the species Bombina variegata from different localities in Slovakia

Abstract

The work is focused on the study of ventral spotting of the yellow-bellied toad (Bombina variegata) depending on different localities. The individuals analysed in this study come from four localities (Rosina, Žilina, Spišská Magura and Bukovské vrchy), which are quite spatially separated. The research was based on photographs of the abdominal side of individuals captured in 2013, 2018, 2020 and 2021. Evaluation of ventral spot patterns was performed using Image-Pro Plus 6.0 software. The resulting factors, determined by the statistical method of PCA (principal components analysis), were correlated with individual morphometry of individuals, sex, location of capture. Subadults had a more yellow abdomen and less variable spots. Spatial spot analysis confirmed that individual populations of frogs differed and showed differences in colouration and abdominal spots in the compared localities. Individuals from Rosina were darker, black spots were more variable in shape, their number was higher, and yellow prevailed in the B/Y ratio. Individuals from Dubeň were darker, with a strong circularity and a lower number of black spots, and a yellow colour predominated in the B/Y ratio. Individuals from Bukovské vrchy were darker, smaller in body size, with more variable and a greater quantity of black spots. Black predominated in the B/Y ratio. Individuals from Spišská Magura were lighter, with a more pronounced circularity of black spots, a high number of black spots, and black colour predominated in the B/Y ratio. We also evaluated microsatellite variation and ecomorphological differences in B. variegata from the locality Bukovské vrchy (Carpathian primeval beech forests, Poloniny National Park). We amplified 5 microsatellite loci, of which 4 were used to perform further fragmentation analysis. The number of alleles per locus ranged from 1 to 9. The observed heterozygosity ranged from 0 to 0.925 and expected heterozygosity from 0 to 0.846. Deviation from the Hardy-Weinberg equilibrium was not detected.