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15 mai 2017

Biogeographic links between southern Atlantic Forest and western South America : rediscovery, re-description, and phylogenetic relationships of two rare montane anole lizards from Brazil [Molecular Phylogenetics and Evolution]

Keywords : Anolis, Dactyloidae, Dactyloa, biogeography, Mainland, Atlantic Forest

Data on species ranges and phylogenetic relationships are key in historical biogeographical inference. In South America, our understanding of the evolutionary processes that underlie biodiversity patterns varies greatly across regions. Little is known, for instance, about the drivers of high endemism in the southern montane region of the Atlantic Rainforest. In this region, former biogeographic connections with other South American ecosystems have been invoked to explain the phylogenetic affinities of a number of endemic taxa. This may also be the case of the montane anole lizards Anolis nasofrontalis and A. pseudotigrinus, known from few specimens collected more than 40 years ago. We combine new genetic data with published sequences of species in the Dactyloa clade of Anolis to investigate the phylogenetic relationships of A. nasofrontalis and A. pseudotigrinus, as well as estimate divergence times from their closest relatives.(...)

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11 mai 2017

Fish assemblage production estimates in Appalachian streams across a latitudinal and temperature gradient [Ecology of Freshwater Fish]

Keywords : assemblage composition, assemblage evenness, biomass, P/B ratios, secondary production

Production of biomass is central to the ecology and sustainability of fish assemblages. The goal of this study was to empirically estimate and compare fish assemblage production, production-to-biomass (P/B) ratios and species composition for 25 second- to third-order streams spanning the Appalachian Mountains (from Vermont to North Carolina) that vary in their temperature regimes.(...)

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10 mai 2017

Poison frog tadpoles seek parental transportation to escape their cannibalistic siblings [Journal of Zoology]

Keywords : begging behaviours, Dendrobatidae, cannibalism, sibling competition, parental care, Ranitomeya variabilis, poison frog, transportation

Parental care is a limited resource which in many species is acquired by the offspring through begging behaviours and often causes competition between siblings. The Neotropical poison frog Ranitomeya variabilis provides a very specific form of parental care : because its tadpoles are cannibalistic males usually separate them from their siblings after hatching by transporting them singly to small water bodies. However, in some cases parents do not transport their tadpoles but let them all hatch into the same pool. Here, we investigate if abandoned tadpoles of R. variabilis actively seek parental care in form of transportation.(...)

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10 mai 2017

Unconscious selection drove seed enlargement in vegetable crops [Evolution Letters]

Benoît Pujol

Domesticated grain crops evolved from wild plants under human cultivation, losing natural dispersal mechanisms to become dependent upon humans, and showing changes in a suite of other traits, including increasing seed size. There is tendency for seed enlargement during domestication to be viewed as the result of deliberate selection for large seeds by early farmers. However, like some other domestication traits, large seeds may have evolved through natural selection from the activities of people as they gathered plants from the wild, or brought them into cultivation in anthropogenic settings. Alternatively, larger seeds could have arisen via pleiotropic effects or genetic linkage, without foresight from early farmers, and driven by selection that acted on other organs or favored larger plants. We have separated these unconscious selection effects on seed enlargement from those of deliberate selection, by comparing the wild and domesticated forms of vegetable crops.(...)

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10 mai 2017

The effects of ant nests on soil fertility and plant performance : a meta-analysis [Journal of Animal Ecology]

Keywords : ants, ecological engineers, soil disturbance

1.Ants are recognized as one of the major sources of soil disturbance world-wide. However, this view is largely based on isolated studies and qualitative reviews. Here, for the first time, we quantitatively determined whether ant nests affect soil fertility and plant performance, and identified the possible sources of variation of these effects.
2.Using Bayesian mixed-models meta-analysis, we tested the hypotheses that ant effects on soil fertility and plant performance depend on the substrate sampled, ant feeding type, latitude, habitat and the plant response variable measured.(...)

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