Variability of the baculum in the red fox (Vulpes vulpes) from Slovakia

Abstract

Despite a large number of studies on the variability of the baculum (os penis) in several orders of mammals, detailed data about the baculum of Vulpes vulpes are very few. The aim of this study was to investigate the data on quantitative characteristics of the size of the baculum and describe the variability of the baculum of V. vulpes from the transition region between the Eastern and Western Carpathians (Slovakia). The study presents the morphological variation in 10 traits of the baculum based on an analysis of 119 bacula of mature males collected in north-eastern Slovakia (near the town of Bardejov, Slovak Carpathians) during the years 1960-1981. According to descriptive statistics, bacula are variable in size. Moreover, a principal component analysis revealed strong positive correlation between several traits, mainly between the length of the baculum and the length of sulcus urethralis, dorsoventral thickness (proximal) and laterolateral thickness (proximal), dorsoventral thickness (distal) and laterolateral thickness (distal), dorsoventral thickness (middle) and laterolateral thickness (proximal), and the width of sulcus urethralis and laterolateral thickness (middle). These results of positive correlation between the length and width dimensions of the penis bone, especially of the proximal and distal end, could explain their relationship to protect the bone and urethra before fracture during copulation.Atlikta nemažai tyrimų apie kai kurių žinduolių būrių atstovų varpikaulius (os penis), tačiau išsamių duomenų apie rudosios lapės (Vulpes vulpes) varpikaulį yra mažai. Pristatomo darbo tikslas -išanalizuoti V. vulpes varpikaulio matmenis ir apibūdinti šio kaulo kintamumą Slovakijos regione, esančiame tarp Rytų ir Vakarų Karpatų kalnų. Pagal dešimt morfologinių požymių išmatuota 119 rudųjų lapių varpikaulių. Tyrimams buvo naudojama šiaurės rytų Slovakijoje netoli Bardejovo miesto 1960-1981 metais surinkta medžiaga. Statistinė matmenų analizė parodė, kad suaugusių lapių patinų varpikauliai yra nevienodo dydžio. Atlikus pagrindinių komponentų analizę išaiškinta stipri teigiama koreliacija tarp šių matmenų: varpikaulio ilgio ir sulcus urethralis ilgio, dorsoventralinio (proksimalinio) varpikaulio pločio ir laterolateralinio (proksimalinio) pločio, dorsoventralinio (distalinio) varpikaulio pločio ir laterolateralinio (distalinio) pločio, dorsoventralinio (vidurinio) varpikaulio pločio ir laterolateralinio (proksimalinio) pločio, taip pat tarp sulcus urethralis pločio ir laterolateralinio (vidurinio) varpikaulio pločio. Tokia koreliacija tarp varpikaulių ilgio ir pločio matmenų, ypač tarp proksimalinio ir distalinio galo, gali paaiškinti jų vaidmenį apsaugant kaulą ir šlaplę nuo lūžio kopuliacijos metu.

Morphological variation and allometry of the baculum in stoats, Mustela erminea (Carnivora, Mustelidae) from Western Carpathians

“…Similar analysis in this study confirmed that the bacular length was well correlated with head-and-body length. Positive correlations between the bacular dimensions between each other as well with the baculum weight confirmed their relationship to provide mechanical support during copulation and interact more directly with the female reproductive tract (Baryshnikov et al 2003, Čanády 2013, Čanády & Čomor 2013, Ča nády & Onderková 2016a. Reutte et al (2015) proved sexual size dimorphism in favour of males for both species (Martes martes and M. foina) for somatic measures.…”

“…The bone size served as a reliable indicator of good genes to female mates during breeding (Krawczyk et al 2011). In our previous studies of the baculum in carnivores from Western Carpathians were proved that bacular length was generally less variable than other thickness measurements (Čanády 2013(Čanády , Čanády & Čomor 2013(Čanády , Čanády & Onderková 2016a. This may be due to the ease of measurement (measurement error), because length measurements are basically error-free.…”

“…Bacular length was measured to ±0.01 mm with a digital calliper, and mass was weighed with a digital balance to ±0.01 g. All bacula were measured according to Čanády 2013Čanády , Čanády and Čomor 2013Čanády , Čanády and Onderková 2016a. The measurements collected are described in Figure 1a-b and they include: LeBa -baculum length (1-1´), DvThp -dorsoventral thickness of proximal end (2-2´), DvThd -dorsoventral thickness of distal end (3-3´), LtLtThp -laterolateral thickness of proximal end (4-4´), LtLtThd -laterolateral thickness of distal end (5-5´) and finally the WeBa -baculum weight.…”

Allometry of the baculum in the wolf (Canis lupus, Canidae) as an indicator of viability and quality in males

“…mechanically, than the latter. In addition, it should also be noted that several authors (Malecha, Krawczyk, and Hromada 2009;Schwery et al 2011;Čanády 2013;Čanády and Čomor 2013) confirmed a lower variability in the length of the penis bone and a greater variability in its thickness. These observations together with positive correlations between the measured parts of the baculum can play an important role in increasing the strength of the bone and preventing its possible fracture during copulation.…”

“…However, Bonduriansky (2007) stated that the interpretations of allometric relationships in the context of sexual selection must be carefully considered. Several data are available on baculum variability in family Canidae (Pohl 1911;Burt 1960;Harrison and Bates 1989;Lariviére and Ferguson 2002;Dixson and Anderson 2004;Gültiken et al 2004;Sharir et al 2011;Čanády 2013;Čanády and Čomor 2013;Lundy 2014). Nevertheless, all previous studies have analysed only variability in baculum size.…”