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Murviel-lès-Montpellier, France

Jane Bradbury E.,University of Wisconsin - Madison | Duputie A.,Center dEcologie Fonctionnelle et Evolutive 5175 | Deletre M.,CNRS Eco-anthropology and Ethnobiology | Deletre M.,Trinity College Dublin | And 7 more authors.
American Journal of Botany

Premise of the study: Manioc (Manihot esculenta subsp. esculenta), one of the most important tropical food crops, is commonly divided according to cyanide content into two use-categories, "sweet" and "bitter." While bitter and sweet varieties are genetically differentiated at the local scale, whether this differentiation is consistent across continents is yet unknown. Methods: Using eight microsatellite loci, we genotyped 522 manioc samples (135 bitter and 387 sweet) from Ecuador, French Guiana, Cameroon, Gabon, Ghana, and Vanuatu. Genetic differentiation between use-categories was assessed using double principal coordinate analyses (DPCoA) with multivariate analysis of variance (MANOVA) and Jost's measure of estimated differentiation (Dest). Genetic structure was analyzed using Bayesian clustering analysis. Key results: Manioc neutral genetic diversity was high in all sampled regions. Sweet and bitter manioc landraces are differentiated in South America but not in Africa. Correspondingly, bitter and sweet manioc samples share a higher proportion of neutral alleles in Africa than in South America. We also found seven clones classified by some farmers as sweet and by others as bitter. Conclusions: Lack of differentiation in Africa is most likely due to postintroduction hybridization between bitter and sweet manioc. Inconsistent transfer from South America to Africa of ethnobotanical knowledge surrounding use-category management may contribute to increased hybridization in Africa. Investigating this issue requires more data on the variation in cyanogenesis in roots within and among manioc populations and how manioc diversity is managed on the farm. © 2013 Botanical Society of America. Source

Mavoungou J.F.,Institute Of Recherche En Ecologie Tropicale Iret | Mavoungou J.F.,Universite des Sciences et Techniques de Masuku | Kohagne T.L.,University of Yaounde I | Acapovi-Yao G.L.,University Of Cocody Abidjan Cote Divoire | And 3 more authors.
African Journal of Ecology

The vertical distribution of Stomoxys spp. was studied in a rainforest area, Ipassa-Makokou biosphere reserve located in the Ivindo National Park of Gabon. From April to June 2006, Vavoua traps were set out during 15 consecutive days per month at different heights above ground level corresponding to vertical layers of rainforest: 50cm, 10, 20 and 30m. Stomoxys calcitrans, S.transvittatus, S.omega, S.niger niger and S.niger bilineatus were more abundant at near ground level (50cm), whereas abundance of S.xanthomelas was greatest in traps higher (20 and 30m) in the canopy. Fly abundance was significantly different among vertical layers of the forest (H=36.91; P<0.001, ddl=3), and among species to another (H=41.11, P<0.001). Vertical distribution of fly species corroborates feeding behaviour as the identification of blood meal origins showed heterogeneity of feeding hosts. High densities of flies were also observed at 10m, and most S.inornatus were captured at that level. These results show that Stomoxyine flies in this rainforest are present in all vertical layers, from the ground level to the canopy. Their ubiquity, regarding both their habitats and their hosts, should be taken into account if a vector control strategy is planned in this touristic area. © 2012 Blackwell Publishing Ltd. Source

Song W.,Max Planck Institute for Chemistry | Staudt M.,Center dEcologie Fonctionnelle et Evolutive 5175 | Bourgeois I.,Center dEcologie Fonctionnelle et Evolutive 5175 | Williams J.,Max Planck Institute for Chemistry

Plants emit significant amounts of monoterpenes into the earth's atmosphere, where they react rapidly to form a multitude of gas phase species and particles. Many monoterpenes exist in mirror-image forms or enantiomers. In this study the enantiomeric monoterpene profile for several representative plants (Quercus ilex L., Rosmarinus officinalis L., andPinus halepensis Mill.) was investigated as a function of chemotype, light and temperature both in the laboratory and in the field. Analysis of enantiomeric monoterpenes from 19Quercus ilexindividuals from Southern France and Spain revealed four regiospecific chemotypes (genetically fixed emission patterns). In agreement with previous work, onlyQuercus ilexemissions increased strongly with light. However, for all three plant species no consistent enantiomeric variation was observed as a function of light, and the enantiomeric ratio of α-pinene was found to vary by less than 20% from 100 and 1000 μmol m-2 s-1 PAR (photosynthetically active radiation). The rate of monoterpene emission increased with temperature from all three plant species, but little variation in the enantiomeric distribution of α-pinene was observed with temperature. There was more enantiomeric variability between individuals of the same species than could be induced by either light or temperature. Field measurements of α-pinene enantiomer mixing ratios in the air, taken at aQuercus ilexforest in Southern France, and several other previously reported field enantiomeric ratio diel cycle profiles are compared. All show smoothly varying diel cycles (some positive and some negative) even over changing wind directions. This is surprising in comparison with variations of enantiomeric emission patterns shown by individuals of the same species. © 2014 Author(s). Source

Coreau A.,Center dEcologie Fonctionnelle et Evolutive 5175 | Treyer S.,Agro ParisTech | Cheptou P.,Center dEcologie Fonctionnelle et Evolutive 5175 | Thompson J.D.,Center dEcologie Fonctionnelle et Evolutive 5175 | Mermet L.,Agro ParisTech

In a mainly experimental science based traditionally on hypothesis testing such as ecology, studying futures may be difficult. However, in the last few decades, predicting the consequences of global changes on the dynamics and function of ecological systems has become a major challenge in ecological research. To study how ecological scientists deal with potential difficulties in studying futures, we adopted a reflexive viewpoint on how scientists address the study of ecological futures. To do so we questioned a panel of ecological scientists on their practical involvement and point of view. Quantitative and qualitative analyses of their responses showed that predictions or predictive models were the dominant theme. Many quantitative models, based on statistical correlations, empirical rules or processes have been developed and their methodological limitations explored by the researchers we interviewed. In a small proportion of studies, qualitative scenarios have been elaborated to explore the range of possible futures. Interviewees emphasized the problem of dealing with ecological complexity and multiple future possibilities. Specificities of futures compared to past or present events were not fully identified. In fact, researchers studying futures mainly adopted a reductionist approach, trying to simplify complex ecological systems. But methods and tools promoted by such an approach to science may not always be appropriate to deal with future ecological complexity. Indeed, an emphasis on prediction prevents ecologists from acknowledging the multiplicity and undetermined nature of futures. © 2010 The Authors. Source

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