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Parasites have been considered important components of their ecosystems since they can modify food-web structures and functioning. One constraint to the inclusion of parasites in food-web models is the scarcity of available information on their feeding habits and host–parasite relationships. The isotopic approach was used to determine the trophic position and feeding habits of gyrocotylidean tapeworm (Gyrocotyle urna) and its host, the holocephalan (Chimaera monstrosa). Similar to other studies with parasites, the ID values of the parasite–host system were negative for both isotopic values of N and C, independent of the sex and size of the host. The importance of using specific ID in parasite–host systems is illustrated to avoid potential errors in the interpretation of the results when surrogate values from similar systems or organisms are used. informacion[at] Navarro et al (2014) Isotopic discrimination of stable isotopes of nitrogen and carbon in a host-specific holocephalan tapeworm. J Helminthology 88: 371–375. Doi 10.1017/S0022149X13000126
The relationship between genetic diversity and fitness, a major issue in evolutionary and conservation biology, is expected to be stronger in traits affected by many loci and those directly influencing fitness. The influence of heterozygosity on individual survival, one of the most important parameters determining individual fitness, was explored by following individual survival up to recruitment of 863 fledgling pied flycatchers (Ficedula hypoleuca). Whereas individual heterozygosity did not influence juvenile or adult survival, the genetic relatedness of parents was negatively associated with their offspring’s survival during adult life, but this effect was not apparent from fledgling to recruitment. This work highlights the need of studies exploring heterozygosity-fitness correlations at different life stages, in populations with different demographic histories and under variable environmental conditions to increase our knowledge on the causes of such correlations. informacion[at] Canal et al (2014) Exploring Heterozygosity-Survival Correlations in a Wild Songbird Population: Contrasting Effects between Juvenile and Adult Stages. PLoS ONE 9(8): e105020. Doi 10.1371/journal.pone.0105020
Several major developments in theoretical ecology have relied on either dynamical stability or numerical simulations, but oftentimes, they have found contradictory results. This is partly a result of not rigorously checking either the assumption that a steady state is feasible—meaning, all species have constant and positive abundances—or the dependence of results to model parameterization. Here, the concept of structural stability is extended to community ecology in order to account for these two problems. Specifically, the set of conditions leading to the stable coexistence of all species was studied within a community. This shifts the question from asking whether we can find a feasible equilibrium point for a fixed set of parameter values, to asking how large is the range of parameter values that are compatible with the stable coexistence of all species. informacion[at] Rohr et al (2014) On the structural stability of mutualistic systems. Science 345: 1253497. Doi 10.1126/science.1253497


    Estación Biólogica de Doñana - Consejo Superior de Investigaciones Científicas - Apdo 1056 E - 41013 Sevilla
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