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Di Cerbo A.R.,Centro Studi Faunistica Dei Vertebrati | Biancardi C.M.,Centro Studi Faunistica Dei Vertebrati
Amphibia Reptilia | Year: 2012

In this study, we explored the level and pattern of sexual size dimorphism and sexual shape dimorphism in two closely related Bombina species that have low levels of sexual dimorphism in body size and shape. We applied an experimental protocol to explore sexual variations in morphological traits, including a preliminary evaluation of the measurement error. Mean measurement error (MME) and measurement error index (MEI) were estimated on each of the eleven morphometric variables to exclude any possible subjective factor in measuring and to perform, for the first time, an objective functional and statistical evaluation of sexual size differences in the two species. Even if statistically significant, each difference that lies below the level of uncertainty of the measure could not be reliable. Therefore, statistically significant differences in head shape have been rejected, due to an average difference between males and females smaller than the possible MME. We detected significantly longer distal segments of the hind limbs in males, which could account for their use in mating behaviour (e.g. scramble competition, water-wave communication). However, major and more reliable evidences of sexual dimorphism have been found on forelimb measures (MEI > 1), in particular humerus length and amplexus, which are significantly larger in males than in females. These results indicate a mating related sexual dimorphism, when larger and stronger forelimbs can give an advantage during coupling as well as during male-male fighting. The mean measurement error values and formulas provided in this work could be applied to future morphometric studies on Bombina species. © Koninklijke Brill NV, Leiden, 2012. Source


di Cerbo A.R.,Centro Studi Faunistica Dei Vertebrati | Biancardi C.M.,Centro Studi Faunistica Dei Vertebrati
Acta Herpetologica | Year: 2010

The tadpoles of Yellow-bellied toad (Bombina variegata) can be easily recognized from other Italian anuran species, except those of B. pachypus (though the two congeneric species are allopatric). In this paper we report morphometric data on B. variegata tadpoles from a Lombard population living near a torrent at 450 m a.s.l. On a sample of 264 tadpoles (stages 19-44, according to Gosner, 1960) we measured the following five variables: snout-vent length, tail length, maximum tail height, total length and weight. We found a slight allometric relationship between snout-vent length and tail length, while, as expected, the weight is nearly proportional to the cube of linear measures. According to literature data, our results point to highly constant proportions during the development phases up to prometamorphic stages. Te ratio between snout-vent length and tail length was about 0.75 during the whole growing phase, while from stage 42 the proportion increases as the resorption of the tail starts. © Firenze University Press. Source


Di Cerbo A.R.,Centro Studi Faunistica Dei Vertebrati | Biancardi C.M.,Centro Studi Faunistica Dei Vertebrati
Acta Theriologica | Year: 2013

Camera trapping has been widely applied to studies of medium to large terrestrial mammals, but its application to small arboreal mammals has hardly been tested. We employed camera trapping and other conventional monitoring methods during a mammal survey in a Site of Community Importance located within the Adda North Regional Park (Lombardy, Italy). Camera trapping was particularly successful for monitoring arboreal mammals, allowing the first detection of presence of the invasive grey squirrel (Sciurus carolinensis) in an area occupied by indigenous red squirrels (Sciurus vulgaris) and the collection of a large amount of data on squirrels and common dormice (Muscardinus avellanarius). When triggered, cameras were set to record short video clips (10 to 40 s). More than 400 events were recorded and analysed, mainly from the autumn and winter months. The daily activity pattern of both species displayed a trend from two to three activity peaks in summer to a unimodal pattern in winter, with the peaks of the two species temporally separated. Camera trapping could be a useful method also when applied to monitoring small mammals, particularly endangered arboreal or invasive alien species. For instance, the monitoring of the spread of S. carolinensis is particularly important, where the early detection of new population can be crucial for the conservation of indigenous European species. Camera trapping can be an effective addition to traditional survey methods. It provides a simple non-invasive technique for collecting a large amount of data per device with limited human effort. © 2012 Mammal Research Institute, Polish Academy of Sciences, Białowieża, Poland. Source

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