Es descobreix un patró d'ossificació comú en els ungulats

Tots els vertebrats tenim un esquelet ossi. Però la formació dels ossos varia entre individus i entre espècies. Investigadors de la UAB han trobat un patró d'ossificació en els Ungulats, nom genèric de qualsevol mamífer les extremitats del qual acaben en peülles, diferent en funció de si els ossos estan sotmesos a tensions o a pressions. Aquesta nova aproximació pot ser aplicada a l'estudi de fòssils de mamífers extints i ser útil tant per establir relacions filogenètiques de parentiu com per conèixer aspectes funcionals de l'evolució dels vertebrats.Todos los vertebrados tenemos un esqueleto óseo. Pero la formación de los huesos varía entre individuos y entre especies. Investigadores de la UAB han encontrado un patrón de osificación en los Ungulados, nombre genérico de cualquier mamífero cuyas extremidades terminan en pezuñas, diferente en función de si los huesos están sometidos a tensiones o presiones. Esta nueva aproximación puede ser aplicada al estudio de fósiles de mamíferos extintos y ser útil tanto para establecer relaciones filogenéticas de parentesco como para conocer aspectos funcionales de la evolución de los vertebrados

Mismeasure of secondary sexual traits: An example with horn growth in the Iberian ibex

Monitoring programmes and studies focused on secondary sexual characters (SSCs) depend on the accuracy of measurements. However, methods of measurements of SSC, such as horns of ungulates, vary throughout the literature. Thus, the accuracy of horn growth measurements as proxies of true horn growth and the comparability of results inferred from different horn growth measurements may be questionable. We used the horns of Iberian ibex Capra pyrenaica to compare horn growth measurements and to analyse reliability with true horn growth. Our results reveal that measurements used in previous studies differed substantially from true horn growth and volume estimated as a barrel appeared as the best proxy of annular segments of horns in the Iberian ibex. Horn growth measurements are not necessarily mutually comparable, just as classical measurements are not necessarily representative of true horn growth. We discuss the wider implications of these results and suggest that biological processes linked to horns of ungulates should be reappraised using improved and accurate measurements because horn growth pattern is a key factor in sustainable management and conservation plans of ungulate species around the world. © 2012 The Authors. Journal of Zoology © 2012 The Zoological Society of London.Peer Reviewe

Negative effect of the arthropod parasite, Sarcoptes scabiei, on testes mass in Iberian ibex, Capra pyrenaica

Testes mass is a key factor in male reproductive success and is potentially exposed to so-called 'parasitic castration'. This is the result of the direct destruction or alteration of reproductive cell lineages (parasitic castration sensu stricto), or the indirect detrimental effects - for example, via body condition - on the ability of progenitors to produce or rear offspring (parasitic castration sensu lato). There are enormous gaps in our knowledge on the effects of parasites on the testes of wild mammals and in an attempt to rectify this dearth of data we examined the relationship between the skin parasite Sarcoptes scabiei and testes mass in Iberian ibex Capra pyrenaica. We considered data from 222 males that were culled in the population from the Sierra Nevada in Spain. Our results provide evidence that sarcoptic mange is associated with reduced size-corrected testes mass in Iberian ibex which supports the hypothesis that parasitism is a determining factor in gonad plasticity in male mammals. We discuss several hypothetical causes of this relationship and highlight the need to deepen the sub-lethal effects of pathogens if we are to accurately understand their modulator effects on host population dynamics. © 2010 Elsevier B.V.Peer Reviewe

Common names of species, the curious case of Capra pyrenaica and the concomitant steps towards the 'wild-to-domestic' transformation of a flagship species and its vernacular names

Common names (CN) add to linguistic richness and ultimately derive from how a majority of people refer to a species. CN have a biological and-above all-practical importance given that they are essential for connecting specialists and lay people. To illustrate the diversity of CN between and within species, we made an overview of common name in Caprinae species-flagship species in mountain ecosystems. Then, using Capra pyrenaica as a study case, we highlighted that the choice of CN is inextricably linked to current debates and trends in wildlife management that should never be ignored, given their importance in the fields of ethics, zoology, systematics, conservation and current management. We underline the need to investigate further the probable relationships linking common names, human perception and wildlife management. Researchers, citizens and policy-makers will have to be watchful that clumsy common names, such as 'wild-to-domestic' transformed ones, will not hamper the conservation of wild species as a 'Common Heritage'. © 2011 Springer Science+Business Media B.V.Peer Reviewe

Mismeasure of secondary sexual traits: An example with horn growth in the Iberian ibex

Monitoring programmes and studies focused on secondary sexual characters (SSCs) depend on the accuracy of measurements. However, methods of measurements of SSC, such as horns of ungulates, vary throughout the literature. Thus, the accuracy of horn growth measurements as proxies of true horn growth and the comparability of results inferred from different horn growth measurements may be questionable. We used the horns of Iberian ibex Capra pyrenaica to compare horn growth measurements and to analyse reliability with true horn growth. Our results reveal that measurements used in previous studies differed substantially from true horn growth and volume estimated as a barrel appeared as the best proxy of annular segments of horns in the Iberian ibex. Horn growth measurements are not necessarily mutually comparable, just as classical measurements are not necessarily representative of true horn growth. We discuss the wider implications of these results and suggest that biological processes linked to horns of ungulates should be reappraised using improved and accurate measurements because horn growth pattern is a key factor in sustainable management and conservation plans of ungulate species around the world. © 2012 The Authors. Journal of Zoology © 2012 The Zoological Society of London.Peer Reviewe

Causes and consequences at individual scale of infestation by sarcoptic mange Sarcoptes scabiei in Iberian ibex Capra pyrenaica

TOULOUSE3-BU Sciences (315552104) / SudocSudocFranceF

Revisiting an old question: Which predators eat eggs of ground-nesting birds in farmland landscapes?

International audienceNest predation is a major cause of reproductive failure in birds, but predator identity often remains unknown. Additionally, although corvids are considered major nest predators in farmland landscapes, whether breeders or floaters are involved remains contentious. In this study, we aimed to identify nest predators using artificial nests, and test whether territorial or non-breeders carrion crow (Corvus corone) and Eurasian magpie (Pica pica) were most likely involved. We set up an experiment with artificial ground nests (n = 1429) in farmland landscapes of western France, and assessed how different combinations of egg size and egg material (small plasticine egg, large plasticine egg, quail and natural hen eggs) might influence predation rates and predator species involved. Nest predators were identified using remotely triggered cameras and marks left in plasticine eggs. Corvids were by far the predators most involved (almost 80% of all predation events), independent of egg type. Carrion crows alone were involved in 60% of cases. Probability of predation increased with egg size, and predation rate was higher for natural than for artificial eggs, suggesting that, in addition to egg size, predators might perceive plasticine and natural eggs differently. Predation rates of artificial nests by corvids were related significantly to corvid abundance, and far more to breeder than floater abundances, for both carrion crows and magpies. This study emphasizes the importance of identifying predators at species level, and considering their social status when assessing corvid abundance impact on prey population dynamics. Combining camera traps and plasticine eggs can achieve this objective. Given the high predation rate by carrion crows, a better understanding of landscape-mediated changes in predator diet seems mandatory to design mitigation schemes able to confront ecological challenges raised by generalist predators

Pseudoectoparasites: a new tool for exploring the relationship between host behaviour and ectoparasites

Peer Reviewe

Advances in studies of disease-navigating webs: Sarcoptes scabiei as a case study

The discipline of epidemiology is the study of the patterns, causes and effects of health and disease conditions in defined anima populations. It is the key to evidence-based medicine, which is one of the cornerstones of public health. One of the important facets of epidemiology is disease-navigating webs (disease-NW) through which zoonotic and multi-host parasites in general move from one host to another. Epidemiology in this context includes (i) classical epidemiological approaches based on the statistical analysis of disease prevalence and distribution and, more recently, (ii) genetic approaches with approximations of disease-agent population genetics. Both approaches, classical epidemiology and population genetics, are useful for studying disease-NW. However, both have strengths and weaknesses when applied separately, which, unfortunately, is too often current practice. In this paper, we use Sarcoptes scabiei mite epidemiology as a case study to show how important an integrated approach can be in understanding disease-NW and subsequent disease control.Project support was provided by Proyecto de Excelencia RNM 06400 (Junta de Andalucia, Spain) and Juan de la Cierva Grant (MinisterioInnovación y ciencia, Spain), the Special Fund for Agro-scientific Research in the Public Interest (Grant No. 201303037), the PRIN 2010/2011 Grant (Ministero Università e Ricerca, Italy, Code D11J2000360001) and the Science Fund for Creative Research Groups of Gansu Province (Grant No. 1210RJIA006).Peer Reviewe