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4 mai 2016

Comparative Phylogeography Reveals Cryptic Diversity and Repeated Patterns of Cladogenesis for Amphibians and Reptiles in Northwestern Ecuador [Plos One]

Subject Areas : phylogeography, toes, forests, Ecuador, new species reports, eyelids, mitochondria, reptiles

Comparative phylogeography allow us to understand how shared historical circumstances have shaped the formation of lineages, by examining a broad spectrum of co-distributed populations of different taxa. However, these types of studies are scarce in the Neotropics, a region that is characterized by high diversity, complex geology, and poorly understood biogeography. Here, we investigate the diversification patterns of five lineages of amphibians and reptiles, co-distributed across the Choco and Andes ecoregions in northwestern Ecuador. Mitochondrial DNA and occurrence records were used to determine the degree of geographic genetic divergence within species.(...)

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4 mai 2016

Coevolutionary elaboration of pollination-related traits in an alpine ginger (Roscoea purpurea) and a tabanid fly in the Nepalese Himalayas [New Phytologist]

Keywords : alpine ginger, coevolution, phenotypic selection, Philoliche longirostris, pollination, Roscoea

Geographical variation in the interacting traits of plant–pollinator mutualism can lead to local adaptive differentiation. We tested Darwin’s hypothesis of reciprocal selection as a key driving force for the evolution of floral traits of an alpine ginger (Roscoea purpurea) and proboscis length of a tabanid fly (Philoliche longirostris).
We documented the pattern of trait variation in R. purpurea and P. longirostris across five populations. At each site, we quantified pollinator-mediated selection on floral display area, inflorescence height and corolla length of R. purpurea by comparing selection gradients for flowers exposed to natural pollination and to supplemental hand pollination. Reciprocal selection between plant and fly was examined at two sites via the relationship between proboscis length and nectar consumption (fly benefit) and corolla length and pollen deposition (plant benefit).(...)

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3 mai 2016

The shapes of bird beaks are highly controlled by nondietary factors [PNAS]

Keywords : geometric morphometrics, integration, allometry, birds, modularity

Bird beaks are textbook examples of ecological adaptation to diet, but their shapes are also controlled by genetic and developmental histories. To test the effects of these factors on the avian craniofacial skeleton, we conducted morphometric analyses on raptors, a polyphyletic group at the base of the landbird radiation. Despite common perception, we find that the beak is not an independently targeted module for selection. Instead, the beak and skull are highly integrated structures strongly regulated by size, with axes of shape change linked to the actions of recently identified regulatory genes.(...)

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3 mai 2016

Gut microbial communities of social bees [Nature Reviews Microbiology]

Subject terms : entomology, microbial ecology, microbiome, microbiota, symbiosis

The gut microbiota can have profound effects on hosts, but the study of these relationships in humans is challenging. The specialized gut microbial community of honey bees is similar to the mammalian microbiota, as both are mostly composed of host-adapted, facultatively anaerobic and microaerophilic bacteria. However, the microbial community of the bee gut is far simpler than the mammalian microbiota, being dominated by only nine bacterial species clusters that are specific to bees and that are transmitted through social interactions between individuals.(...)

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29 avril 2016

How does the functional diversity of frugivorous birds shape the spatial pattern of seed dispersal ? A case study in a relict plant species [Phylosophical Transactions of the Royal Society B]

Keywords : Taxus baccata, ecosystem services, gene flow, spatial network, heterogeneous landscape, modularity

Genetic markers used in combination with network analysis can characterize the fine spatial pattern of seed dispersal and assess the differential contribution of dispersers. As a case study, we focus on the seed dispersal service provided by a small guild of frugivorous birds to the common yew, Taxus baccata L., in southern Spain. We build the spatial networks of seed dispersal events between trees and seed-plots within the studied population—local network—and the spatial network that includes all dispersal events—regional network.(...)

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