Search results for "parasitisme"
showing 6 items of 6 documents
Mécanismes de régulation biologique des adventices par les couverts végétaux
2022
La régulation biologique des adventices par les couverts végétaux cultivés peut impliquer différents mécanismes. La compétition pour les ressources est le mécanisme considéré comme prépondérant dans la régulation des adventices par les couverts végétaux. L'allélopathie pourrait également jouer un rôle mais ses effets au champ sont difficiles à démontrer car difficiles à dissocier des effets d'autres mécanismes. Les couverts végétaux peuvent également affecter les adventices en modifiant le microclimat à la surface du sol. La régulation des adventices par les couverts végétaux peut également se faire par l'intervention d'organismes auxiliaires, comme des insectes responsables de prédation (c…
Two new records of Alloxysta (Hymenoptera: Cynipoidea: Figitidae: Charipinae) from Colombia
2016
The Charipinae from Colombia has been recently studied. Nine Charipinae species are known to be present in this country: Alloxysta arcuata (Kieffer, 1902), Alloxysta castanea (Hartig, 1841), Alloxysta consobrina (Zetterstedt, 1838), Alloxysta hansoni Pujade-Villar, 2011, Alloxysta obscurata (Hartig, 1840), Alloxysta medinae Ferrer-Suay & Pujade-Villar, 2012, Alloxysta pilipennis (Hartig, 1840), Alloxysta torresi Ferrer-Suay & Pujade-Villar, 2012 and Phaenoglyphis villosa (Hartig, 1841). Here more Charipinae material has been studied from collections made with Malaise traps by the Humboldt Institute in several places of Colombia. In this study, two species are recorded for the first …
Effect of the host plant on the immunity of a phytophagous insect : influence of grape variety on the ability of the European grapevine moth to defen…
2013
In tritrophic interactions involving phytophagous insects, host plants and natural enemies, trophic levels are highly dependent on each other. Host plant may strongly affect directly phytophagous insect and indirectly natural enemies growing on these phytophagous insects. When a natural enemy attacks a phytophagous insect, the host immune system constitutes the last chance for the host to survive to an infection. A great variation of insect immune system is generally found in populations for susceptibility to pathogens, suggesting that variable selection pressures may have shaped and driven adaptation of immune traits. This project aims to determine the influence of both host plant and natu…
Intraguild interactions between two egg parasitoids of a true bug in semi-field and field conditions.
2014
International audience; Research on interspecific competitive interactions among insect parasitoids has often been characterized by laboratory studies in which host insects are exposed to female parasitoids of different species in various sequences and combinations. In the last years, an increasing number of studies have investigated interspecific interactions under field and semi-field conditions although just a few number of works focused on egg parasitoids. In this work, we undertook a two-year study to investigate interspecific interactions between Trissolcus basalis (Wollaston) (Hymenoptera: Platygastridae) and Ooencyrtus telenomicida (Vassiliev) (Hymenoptera: Encyrtidae), two egg para…
Contamination de Buxus sempervirens L. par Rosellinia buxi sur la Réserve Naturelle de la Combe-Lavaux en Bourgogne
2008
En Bourgogne, sur la Réserve Naturelle de la Combe Lavaux de Gevrey-Chambertin, des buis (Buxus sempervirens L.) se développent, le long de la route départementale en fond de combe. A la base du tronc de certains Buxus sempervirens L., un Ascomycète a été retrouvée, il s’agit de Rosellinia buxi. Aucune autre espèce de Rosellinia ne vient parasiter ces buis. Cependant, cinq autres espèces de Rosellinia ont été trouvées en Bourgogne. R. aquila et R. corticium ont été identifiés sur les feuillus, alors que R. thelena et R. mycophila plutôt sur les résineux. Quant à R. mammoidea, il a été isolé de chèvrefeuilles sauvages. Rosellinia buxi est donc très étroitement inféodé à cette essence, Buxus …
Ecologie moléculaire d'une relation hôte - parasite en contexte insulaire marin. Crabes parasites des oursins spatangues en Mer des Caraïbes
2014
Comparing the population genetic structures of two species documents on the environmental factors and life history traits that shape the dispersal of the individuals. For host-parasite couple, this approach also permits to predict local adaptation of these species. The investigated species in this work are the ectoparasitic crab Dissodactylus primitivus and its sea urchin host Meoma ventricosa, both species being endemic to the Caribbean and neighboring American coasts. Several molecular markers were used, namely microsatellites and cytochrome oxidase I (mitochondrial). Moreover, morphometric analyses (shape) were also done. By studying populations across the Antilles arc and along the Pana…