Time filter

Source Type

Abidjan, Ivory Coast

Kouassi K.I.,Ecole Normale Superieure de Paris | Barot S.,Ecole Normale Superieure de Paris | Laossi K.-R.,Nestle | Gignoux J.,Ecole Normale Superieure de Paris | Zoro Bi I.A.,Nangui Abrogoua University
Forest Ecology and Management

Eremospatha macrocarpa and Laccosperma secundiflorum are two clonal rattan species: through vegetative reproduction each individual, i.e. each genet, may produce several stems that are linked to the same rhizome. To determine the impact of ramet harvest by local human populations in these species, we compared the demography of their ramets and studied the impact of the dynamics of their ramets on the demography of their genets. This also allowed a better analyze of their life-history and demography. Genets were classified in development stages. We counted for each genet the number of alive, new, dead and harvested ramets. We determined the impact of the number of ramets and changes in this number on the genet probability of survival, retrogression and recruitment. Ramet demography differed between the two rattan species. The average numbers of new, harvested and dead ramets are about two times higher in E. macrocarpa than in L. secundiflorum. Furthermore, ramet demography influenced genet demography in both species. The survival of adult genets in E. macrocarpa and juvenile genets in L. secundiflorum increased with the initial number of ramets (about 10% between the lower and higher ramet numbers). The genet probability of retrogression increased in L. secundiflorum and decreased in E. macrocarpa with the initial number of ramets. These results suggest the existence of some physiological integration between the ramets of the two rattan species which leads to some cooperation and competition between ramets, within a genet, and to the compensatory production of new ramets after harvest. Overall, for both species, the links between ramet and genet demography suggest that ramet harvest, at the present harvesting rate, is not detrimental to the studied rattan populations. © 2013 Elsevier B.V. Source

Otani S.,Copenhagen University | Mikaelyan A.,Max Planck Institute for Terrestrial Microbiology | Nobre T.,University of Evora | Hansen L.H.,University of Aarhus | And 6 more authors.
Molecular Ecology

Gut microbes play a crucial role in decomposing lignocellulose to fuel termite societies, with protists in the lower termites and prokaryotes in the higher termites providing these services. However, a single basal subfamily of the higher termites, the Macrotermitinae, also domesticated a plant biomass-degrading fungus (Termitomyces), and how this symbiont acquisition has affected the fungus-growing termite gut microbiota has remained unclear. The objective of our study was to compare the intestinal bacterial communities of five genera (nine species) of fungus-growing termites to establish whether or not an ancestral core microbiota has been maintained and characterizes extant lineages. Using 454-pyrosequencing of the 16S rRNA gene, we show that gut communities have representatives of 26 bacterial phyla and are dominated by Firmicutes, Bacteroidetes, Spirochaetes, Proteobacteria and Synergistetes. A set of 42 genus-level taxa was present in all termite species and accounted for 56-68% of the species-specific reads. Gut communities of termites from the same genus were more similar than distantly related species, suggesting that phylogenetic ancestry matters, possibly in connection with specific termite genus-level ecological niches. Finally, we show that gut communities of fungus-growing termites are similar to cockroaches, both at the bacterial phylum level and in a comparison of the core Macrotermitinae taxa abundances with representative cockroach, lower termite and higher nonfungus-growing termites. These results suggest that the obligate association with Termitomyces has forced the bacterial gut communities of the fungus-growing termites towards a relatively uniform composition with higher similarity to their omnivorous relatives than to more closely related termites. © 2014 John Wiley & Sons Ltd. Source

Edi C.V.,Center Suisse Of Recherches Scientifiques En Cote Divoire | Djogbenou L.,University Abomey Calavi | Jenkins A.M.,Boston College | Regna K.,Boston College | And 6 more authors.
PLoS Genetics

Malaria control relies heavily on pyrethroid insecticides, to which susceptibility is declining in Anopheles mosquitoes. To combat pyrethroid resistance, application of alternative insecticides is advocated for indoor residual spraying (IRS), and carbamates are increasingly important. Emergence of a very strong carbamate resistance phenotype in Anopheles gambiae from Tiassalé, Côte d'Ivoire, West Africa, is therefore a potentially major operational challenge, particularly because these malaria vectors now exhibit resistance to multiple insecticide classes. We investigated the genetic basis of resistance to the most commonly-applied carbamate, bendiocarb, in An. gambiae from Tiassalé. Geographically-replicated whole genome microarray experiments identified elevated P450 enzyme expression as associated with bendiocarb resistance, most notably genes from the CYP6 subfamily. P450s were further implicated in resistance phenotypes by induction of significantly elevated mortality to bendiocarb by the synergist piperonyl butoxide (PBO), which also enhanced the action of pyrethroids and an organophosphate. CYP6P3 and especially CYP6M2 produced bendiocarb resistance via transgenic expression in Drosophila in addition to pyrethroid resistance for both genes, and DDT resistance for CYP6M2 expression. CYP6M2 can thus cause resistance to three distinct classes of insecticide although the biochemical mechanism for carbamates is unclear because, in contrast to CYP6P3, recombinant CYP6M2 did not metabolise bendiocarb in vitro. Strongly bendiocarb resistant mosquitoes also displayed elevated expression of the acetylcholinesterase ACE-1 gene, arising at least in part from gene duplication, which confers a survival advantage to carriers of additional copies of resistant ACE-1 G119S alleles. Our results are alarming for vector-based malaria control. Extreme carbamate resistance in Tiassalé An. gambiae results from coupling of over-expressed target site allelic variants with heightened CYP6 P450 expression, which also provides resistance across contrasting insecticides. Mosquito populations displaying such a diverse basis of extreme and cross-resistance are likely to be unresponsive to standard insecticide resistance management practices. © 2014 Edi et al. Source

Boly V.,CNRS Research team on Innovative Processes | Morel L.,CNRS Research team on Innovative Processes | Assielou N.G.,Nangui Abrogoua University | Camargo M.,CNRS Research team on Innovative Processes
Research Policy

Measuring innovation processes is a major concern for academics and firm managers. This study proposes an innovation capacity (IC) measure framework based on a set of 15 innovation management practices. Every practice is subdivided into multiple criteria which are directly observable phenomena or facts. The statistical method of value test and a multi-criteria approach are adopted to propose a typology of four groups of innovative firms (proactive, preactive, reactive, passive). The features observed on these groups of firms allow the determination of the firms' innovation capacity and are useful for providing recommendations and practical actions for them, with a view to reinforcing it. Data from a sample group of 39 small and medium sized enterprises (SMEs) in the manufacturing industry in Lorraine, France were collected via a field survey and were fed into the model to determine the innovation capacity of the companies. © 2013 Elsevier B.V. All rights reserved. Source

Josens G.,Free University of Colombia | Dosso K.,Nangui Abrogoua University | Konate S.,Nangui Abrogoua University
Insectes Sociaux

Small lenticular soil mounds are scattered in several African savannahs. At Lamto, Côte d’Ivoire, most of these lenticular mounds house nests of Odontotermes aff. pauperans which have to date been thought to have built them. However, repeated observations made in 2000 and 2015 supply several arguments in favour of another hypothesis, namely that after a nest of Macrotermes has been abandoned and eroded, it could be colonized by O. aff. pauperans and subsequently maintained, stabilized, by this latterspecies or possibly recolonized by another Macrotermes society. © 2016 International Union for the Study of Social Insects (IUSSI) Source

Discover hidden collaborations