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Wyszukujesz frazę "Borczyk, Bartosz" wg kryterium: Autor


Wyświetlanie 1-8 z 8
Tytuł:
Sexual dimorphism and allometry in the head and body size of two viperid snakes (genus Vipera)
Autorzy:
Bury, Stanisław
Borczyk, Bartosz
Puszkiewicz, Przemysław
Opis:
Sexual dimorphism in the size and shape of the body and head is the result of manifold selective pressures acting on organisms. In snakes, sexual size dimorphism is common and has been well-studied. However, intersexual differences in relative head size and shape have attracted far less attention. Similarly, the allometric properties of head shape and size in snakes are poorly known. Here, we analyse sexual dimorphism in two viperid species: European adder Vipera berus (Linnaeus, 1758) and Steppe viper Vipera renardi (Christoph, 1861). We measured body length, tail length and several head characteristics: head length, head width, head height, pileus length, interorbital distance and internarial distance. Our findings were that males and females of both species did not differ in body length (SVL), but that males tended to have significantly longer tails; there were also significant differences in head characteristics - males tended to have higher heads, and larger internarial and interorbital distances. The head dimensions displayed negative allometry when compared against SVL but when scaled against head length, dimensions like head height and head width exhibited positive allometry. We argue that these differences may be related to sexual selection and that the wider heads may also serve as antipredatory signal.
Dostawca treści:
Repozytorium Uniwersytetu Jagiellońskiego
Artykuł
Tytuł:
Sexual dimorphism and skull size and shape in the highly specialized snake species, Aipysurus eydouxii (Elapidae: Hydrophiinae)
Autorzy:
Kusznierz, Jan
Borczyk, Bartosz
Bury, Stanisław
Paśko, Łukasz
Opis:
Snakes exhibit sexual dimorphism in both head size and shape. Such differences are often attributed to different reproductive roles and feeding habits. We aim to investigate how sexual dimorphism is displayed in the highly specialised fish-egg-eating snake, Aipysurus eydouxii , by analysing two complementary features: body size and skull morphology. We used data on body length, weight, and skull shape from 27 measurements of 116 males and females of A. eydouxii . We investigated both sexual dimorphism and allometric (multivariate and bi-variate) properties of skull growth in the analysed data set. We found that although there was female-biased sexual size dimorphism in body length, females were not heavier than males, contrary to what is commonly observed pattern among snakes. Moreover, females tend to possess relatively smaller heads than males. However, we only found very subtle differences in skull shape reflected in nasal width, mandibular fossa, quadrate crest and quadrate length. We suggest that the feeding specialisation in A. eydouxii does not allow for an increase in body thickness and the size of the head above a certain threshold. Our results may be interpreted as support for prey-size divergence as a factor driving skull dimorphism since such species in which the sexes do not differ in prey size also shows very subtle or no differences in skull morphology.
Dostawca treści:
Repozytorium Uniwersytetu Jagiellońskiego
Artykuł
Tytuł:
Is the blue-spotted phenotype more widespread in the eastern slow worm Anguis colchica (Nordmann, 1840) than the western slow worm Anguis fragilis Linnaeus, 1758 and does it correlate with the male body size? : a case study from Central Europe
Autorzy:
Borczyk, Bartosz
Skórzewski, Grzegorz
Najbar, Bartłomiej
Zając, Bartłomiej
Bury, Stanisław
Kurek, Katarzyna
Kolanek, Aleksandra
Opis:
The blue-spotted phenotype in a slow worm can be considered as an alternative colour morph or a second- ary sexual characteristic. This phenotype is known to entail an elevated predation risk; thus, its continuous presence in a population must be balanced by additional and positive fitness consequences. In this study, we show that blue-spotted males are characterised by a greater snout-vent length (SVL) than typical speci- mens. Importantly, the SVL of blue-spotted males reaches the magnitude of the average female size. This indicates that the presence of blue spots may involve a correlated positive effect on growth and body size. The greater body size of the blue-spotted males could enhance their survival and mating success, and thus facilitate the continued presence of a high fraction of this morph within the population. In addition, we found that the blue-spotted phenotype is more common in the eastern than the western slow worm, and the proposed fitness consequences of the blue-spotted phenotype might enhance its tendency to spread in the eastern Anguis lineage.
Dostawca treści:
Repozytorium Uniwersytetu Jagiellońskiego
Artykuł
Tytuł:
Phylogeography and contact zones of the common grass snake in Poland (Squamata: Natricidae: Natrix natrix)
Autorzy:
Mitrus, Sławomir
Zając, Bartłomiej
Fritz, Uwe
Skawiński, Tomasz
Criado‐Flórez, Andrea
Kolenda, Krzysztof
Najbar, Bartłomiej
Jablonski, Daniel
Pabijan, Maciej
Prusak, Beata
Bury, Stanisław
Borczyk, Bartosz
Kurek, Katarzyna
Opis:
Until now, the genetic identity of common grass snakes (Natrix natrix) in Poland remained poorly understood. This study presents the first comprehensive phylogeographic analysis for Poland using mitochondrial DNA sequences (cyt b and ND4 + tRNAs) and 13 nuclear microsatellite loci. A total of 982 individuals from Poland and adjacent countries were analysed. Three mitochondrial lineages were identified, with partially overlapping distributions. A Bayesian cluster analysis of microsatellite data revealed three genetic clusters corresponding to distinct mitochondrial lineages and the subspecies N. n. natrix, N. n. vulgaris, and N. n. scutata, respectively, albeit with extensive admixture. The mitochondrial lineage of the nominotypical subspecies occurs in the centre and west of the country, the lineage of N. n. vulgaris mainly in the south and southeast, and the lineage of N. n. scutata mainly in the very east. However, Poland represents a complex hybrid zone, with widespread admixture and many individuals with mitonuclear discordance, indicating extensive gene flow. Nuclear genomic signatures of N. n. scutata were found to be widely distributed, also far beyond the occurrence of the respective mitochondrial lineage in eastern Poland. This provides evidence for a dynamic hybrid zone moving from the east to the west and for a westward expansion of N. n. scutata. The present phylogeographic pattern reflects complex postglacial range dynamics, namely the admixture of N. n. natrix, a Central European survivor during the last glaciation, with the postglacial invaders N. n. vulgaris from the southeast and N. n. scutata from the east.
Dostawca treści:
Repozytorium Uniwersytetu Jagiellońskiego
Artykuł
    Wyświetlanie 1-8 z 8

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