Search results for "POPULATIONS"
showing 10 items of 493 documents
Modification of hosts' behavior by a parasite: field evidence for adaptive manipulation.
2007
9 pages; International audience; Parasites relying on trophic transmission to complete their life cycles often induce modifications of their host's behavior in ways that may increase their susceptibility to predation by final hosts. These modifications have often been interpreted as parasite adaptations, but very few studies have demonstrated that host manipulation has fitness benefits for the parasite. The aim of the present study was to address the adaptive significance of parasite manipulation by coupling observations of behavioral manipulation to estimates of trophic transmission to the definitive host in the natural environment. We show that the acanthocephalan parasite Pomphorhynchus …
Demonstration of a reef knot microfiber resonator.
2009
We propose a new way to realize a microfiber optical resonator by implementing the topology of a reef knot using two microfibers. We describe how this structure, which includes 4 ports and can serve as an add-drop filter, can be fabricated. Resonances in an all-silica reef knot are measured and good fits are obtained from a simple resonator model. We also show the feasibility of assembling a hybrid silica-chalcogenide reef knot structure.
La Grive à Pieds Jaunes, Turdus lherminieri (Turdidés): une espèce méconnue à valeur patrimoniale.
2013
10 pages; National audience; Les départements et régions d’Outre-Mer présentent une biodiversité remarquable et un fort taux d’endémisme,mais cet endémisme a pour conséquence une plus grande fragilité et un plus grand risque d’extinction. Les enjeuxde conservation de la biodiversité sont alors importants et l’élaboration de mesures de gestion se heurte biensouvent à une profonde méconnaissance de la biologie des espèces. Dans ce contexte, la Grive à Pieds Jaunes,oiseau endémique de quatre îles des Petites Antilles (statut vulnérable, UICN) est un modèle de choix dans la miseen place de mesures de gestion et de conservation. Les premiers résultats d’un programme d’étude dédié à cetteespèce o…
The evolutionary ecology of the immune response.
2008
13 pages
Evolutionary routes leading to host manipulation by parasites
2012
18 pages; International audience
Permineralized coniferophytes from the Autun Basin: specimens from two new localities of Renault zone 3
2015
International audience; Four zones yielding silicified plant remains have been recognized in the Autun Basin by Renault (1893-1896). Zones 2, 3 and 4, characterized by Autunian plants, correspond to the successive formations of Igornay and Muse (lower Autunian), and Surmoulin-Millery (upper Autunian). Their paleobotanical content, together with that preserved as adpressions in the same formations, document paleofloral changes on the western side of the Tethys within a time interval extending from the latest Ghzelian (uppermost Pennsylvanian) to the early Sakmarian (lower Permian) (Broutin et al. 1999). The analyses realized so far indicate a progressive replacement of wetland plants by taxa…
Contribution of studies on suppressive soils to the identification of bacterial biocontrol agents and to the knowledge of their modes of action
2007
International audience
Introduction et dispersion d'une espèce envahissante : le cas de l'ambroisie à feuilles d'armoise (Ambrosia artemisiifolia L.) en France
2011
National audience; Ambrosia artemisiifolia L. (common ragweed) was accidentally introduced into France in the 1860s. Its single vector of introduction in Europe was red clover seeds (Trifolium pratense L.), probably coming from Pennsylvania, United States at the time. A. artemisiifolia was later introduced into France in many places and at different times. This species has no natural or effective seed dispersal mechanisms and the spread of this weed in the territory is ensured by human activities that carry the seeds and create disturbed environments favourable to its development. It is now established in the Rhone Valley and a number of different factors (cropping system evolution, climate…
Généralités sur la résistance aux Produits de Protection des Plantes (PPP)
2015
SPEPôle GEAPSICT2Communication orale invitée; Au niveau d’un individu, la résistance « biologique » correspond à une moindre sensibilité à un PPP en comparaison d’individus sensibles de référence, mesurée au laboratoire. Un individu résistant peut être caractérisé par son facteur de résistance (l’« intensité » ou la « force » de la résistance, correspondant au rapport entre la quantité de PPP requise pour avoir le même effet sur un individu résistant que sur un individu sensible), et son profil (ou spectre) de résistance (la gamme de substances auquel l’individu sera résistant). Le caractère de résistance est transmis aux générations suivantes de bio-agresseurs, car déterminé par une ou des…
Conséquences écologiques et évolutives du flux de gènes entre Brassica napus transgénique et ses apparentés sauvages
2010
In the framework of commercial release for transgenic crops with novel traits, consequences of gene flow and introgression are still one main concern. I explored the ecological and evolutionary consequences of gene flow between oilseed rape (Brassica napus) and its wild relatives, brown mustard (B. juncea) and wild radish (Raphanus raphanistrum), through several experiments carried out in greenhouse, common garden and field in Beijing and Dijon. First, I revised a comprehensive review of the literature about gene flow and its effect on plant fitness in the Brassiceae. Second, I investigated the effects on gene flow of seed size of hybrids between Bt-transgenic oilseed rape and mustard. Smal…