Search results for "colon"
showing 10 items of 2038 documents
Behavioral syndrome in a native and an invasive hymenoptera species
2014
Recent studies have focused on the role of behavior in biological invasions. Individuals may differ consistently in time for several behavioral traits (personality) which covary(behavioralsyndrome)resultingindifferentbehavioraltypes,someofthemfavoring invasion. Social hymenopterans have a strong potential to be invaders and their success depends primarily on the foundresses' ability to found viable colonies. They are expected to be active, explorative and bold for optimally establishing their nest. In Europe, 2 hornet species coexist: the native Vespa crabro and the invasive Vespa velutina. These 2 species may compete for nesting sites and we suggest that the initial success of V. velutina …
Colonisation and diversification of the Zenaida dove (Zenaida aurita) in the Antilles: phylogeography, contemporary gene flow and morphological diver…
2013
12 pages; International audience; Caribbean avifaunal biogeography has been mainly studied based on mitochondrial DNA. Here, we investigated both past and recent island differentiation and micro-evolutionary changes in the Zenaida Dove (Zenaida aurita) based on combined information from one mitochondrial (Cytochrome c Oxydase subunit I, COI) and 13 microsatellite markers and four morphological characters. This Caribbean endemic and abundant species has a large distribution, and two subspecies are supposed to occur: Z. a. zenaida in the Greater Antilles (GA) and Z. a. aurita in the Lesser Antilles (LA). Doves were sampled on two GA islands (Puerto Rico and the British Virgin Islands) and six…
Influence of leaf age on induced resistance in grapevine against Plasmopara viticola
2012
International audience; Sulfated laminarin (PS3) has previously been shown to induce resistance of grapevine leaves against the oomycete Plasmopara viticola, the causal agent of grape downy mildew. Here, we observed that the level of PS3-induced resistance (PS3-IR) was higher in the adult leaf (in position P3) than in the younger, not fully expanded leaf (in position P1, located above P3). By investigating grapevine defense reactions upon PS3 treatment and inoculation, we found that the production of H2O2, of phytoalexins, and the deposition of phenolics were more abundant in P3 than in P1 leaves. In addition, PS3 significantly reduced stomatal colonization by zoospores only in P3 leaves. T…
Burial behaviour by dealates of the termite Pseudacanthotermes spiniger (Termitidae, Macrotermitinae) induced by chemical signals from termite corpses
2011
In order to maintain healthy colonies, termite workers dispose of the cadavers of dead nest mates by cannibalism, burial, or necrophoresis. However, when multiple reproductives found a new colony by pleometrosis, there are no worker castes at the early stages of the foundation to eliminate or isolate the corpses. In this study, we showed that in young pleometrotic colonies, reproductives of Pseudacanthotermes spiniger had the ability to perform this task. Because of the claustral conditions, and the potential inability of the dealates to feed on their own, their behaviour was restricted to the burial of the cadaver within the initial chamber. This burial behaviour, previously not reported i…
New insight into the colonization processes of common voles: inferences from molecular and fossil evidence.
2008
Biologie et Gestion des Populations, Campus International de Baillarguet, Montferrier/Lez, FranceElucidating the colonization processes associated with Quaternary climatic cycles is important in order to understand the distribution of biodiversity and the evolutionary potential of temperate plant and animal species. In Europe, general evolutionary scenarios have been defined from genetic evidence. Recently, these scenarios have been challenged with genetic as well as fossil data. The origins of the modern distributions of most temperate plant and animal species could predate the Last Glacial Maximum. The glacial survival of such populations may have occurred in either southern (Mediterranea…
The mycorrhizal soil infectivity and arbuscular mycorrhizal fungal spore communities in soils of different aged fallows in Senegal
2001
This work was carried out to determine the influence of the duration of fallow and of physico-chemical components of soils on the distribution of endomycorrhizal fungal spores and the mycorrhizal soil infectivity. The mycorrhization of indigenous plants from the fallows was examined and it was concluded that, except for Cassia obtusifolia, fungal colonization was poorly developed. No correlation was established between spore populations and duration of fallow or between grazed and fenced areas. The relationships between abundance of mycorrhizal spores and the physico-chemical characteristics of the soils were markedly variable among species of mycorrhizal fungi. The results did not provide …
Comparative host–parasite population structures: disentangling prospecting and dispersal in the black-legged kittiwake Rissa tridactyla
2005
Although much insight is to be gained through the comparison of the population genetic structures of parasites and hosts, there are, at present, few studies that take advantage of the information on vertebrate life histories available through the consideration of their parasites. Here, we examined the genetic structure of a colonial seabird, the black-legged kittiwake ( Rissa tridactyla ) using seven polymorphic microsatellite markers to make inferences about population functioning and intercolony dispersal. We sampled kittiwakes from 22 colonies across the species’ range and, at the same time, collected individuals of one of its common ectoparasites, the tick Ixodes uriae . Parasites were …
Soil and fertilizer phosphorus : effects on plant P supply and mycorrhizal development
2005
Plants require adequate P from the very early stages of growth for optimum crop production. Phosphorus supply to the crop is affected by soil P, P fertilizer management and by soil and environmental conditions influencing P phytoavailability and root growth. Phosphorus uptake in many crops is improved by associations with arbuscular mycorrhizal fungi. Cropping system and long-term input of P through fertilizers and manures can influence the amount and phytoavailability of P in the system and the development of mycorrhizal associations. Optimum yield potential requires an adequate P supply to the crop from the soil or from P additions. Where early-season P supply is low, P fertilization may…
Arbuscular mycorrhizal fungi in Georgia, the Caucasus region: the first report of species diversity and root colonization
2018
Although the Caucasus region belongs to the world biodiversity hotspots, arbuscular mycorrhizal fungi (AMF) have not been investigated in this area. A total of 11 mixtures of soils and roots from 11 localities in southern Georgia in an altitudinal gradient from 1 to 1560 m a. s. l. were sampled in 2015. AMF spores and arbuscular mycorrhiza were observed in all samples. Eight AMF species were found in the field-collected soils: Acaulospora bireticulata, Acaulospora cavernata, Funneliformis coronatum, Gigaspora gigantea, Glomus rubiforme, Scutellospora dipurpurescens, Septoglomus constrictum, and Septoglomus jasnowskae. The most frequently occurring species proved to be S. constrictum. Labora…
Valorisation of Persimmon and Blueberry By-Products to Obtain Functional Powders: in vitro Digestion and Fermentation by Gut Microbiota
2020
[EN] Globalization of fruit and vegetable markets generates overproduction, surpluses, and potentially valuable residues. The valorization of these byproducts constitutes a challenge, to ensure sustainability and reintroduce them into the food chain. This work focuses on blueberry and persimmon residues, rich in polyphenols and carotenoids, to obtain powders with high added value to be used as ingredients in food formulation. These powders have been characterized, and the changes in the bioactive compounds in in vitro gastrointestinal digestion have been evaluated. The results indicated that the type of residue, the drying process, as well as the content and type of fiber determine the rele…