Effets de l’environnement proche sur la biodiversité entomologique en carottes de plein champ

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Entomological diversity in agro-ecosystems : not necessarily an ecological desert

peer reviewe

Effects of insecticide treatments on insect density and diversity in vegetable open fields.

Vegetable open field areas increased for 15 years in Wallonia, mainly in Hesbaye. To be in accordance with quality standards, especially in terms of agro-chimical residues (R.M.L.), biological pest control was developed and allowed to reduce the insecticide use, leading to have safer fresh products. Among cultivated species in Wallonia, leguminous crops represent more than 85% of the vegetable production. To assess the impact of insecticide treatment on both pests (mainly aphids) and beneficial insects (predators and parasitoids), broad bean (Vicia faba L.) fields were investigated during all the production duration. Twelve fields between Waremme and Hannut were visited weakly from May to July. In each field, control untreated and treated plots were investigated. Insects were caught using yellow traps and determined until the family level. Approximately 90.000 insects belonging to 59 major families (99% of captures) and 64 minor families were identified. These results showed that biodiversity in terms of family numbers was significantly higher in unsprayed plots. In addition, biodiversity and biomass (insect density) increased gradually during the season. Evaluation of pest and beneficial diversity and density was discussed in relation to aphicid (lambda-cyhalothrin, pirimicarb) treatments and the development of I.P.M. program in vegetable crops

Effect of host plants on Brassicacae specialist/ generalist aphids and their natural predator Adalia bipunctata L. (Coleoptera : Coccinellidae)

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Sully tel qu’en lui-même

Les communications rassemblées dans cet ouvrage portent sur Sully lui-même en son temps, sur son héritage et sur la façon dont sa personne et son œuvre ont été perçues à travers les siècles. Ces interventions permettent de faire le point sur les travaux menés depuis une vingtaine d’années, notamment à l’École des chartes, sur le grand ministre d’Henri IV et de dégager de nouvelles pistes de recherches. Cette journée d’études, sous la direction scientifique de Jean-Pierre Babelon, membre de l’institut et président de la société Henry IV, a été organisée le 23 octobre 1999 à l’occasion du transfert des cendres de Maximilien de Béthune, duc de Sully, et de son épouse Rachel de Cochefilet, au château de Sully-sur-Loire

Prognostic value of thallium-201 stress myocardial scintigraphy with exercise ECG after myocardial infarction.

The prognostic value of stress electrocardiogram and thallium-201 stress myocardial scintigraphy was analyzed in 224 patients 3 months after a myocardial infarction; both techniques allowed an adequate stratification based on the presence of ST depression or multivessel disease. Combining stress electrocardiogram and stress myocardial scintigraphy data improved the prognostic ability, particularly in patients who associated multivessel disease and ST depression

Contrasting responses of saproxylic insects to focal habitat resources: The example of longhorn beetles and hoverflies in Belgian deciduous forests

Although both saproxylic longhorn beetles and hoverflies benefit from the presence of woody substrates for reproduction, they differ in their requirements for floral resources and for microbiotopes of overmature and senescent trees. This led us to expect contrasting responses between the two species groups in relation to these essential resources. We examined this prediction in 22 mature oak- and beech-dominated stands of southern Belgium by relating their species assemblages to local vegetation structure and composition, altitude and landscape composition. Stands were organised in pairs as a function of their overall dead wood supply. Free-hanging window traps, stump emergence traps and Malaise traps produced 30 longhorn beetle species (1637 individuals) and 106 hoverfly species (3020 individuals). Paired-comparisons controlling for annual variation in captures showed that, unlike saproxylic hoverflies, stands with dead wood hosted more species and individuals of longhorn beetles. Accordingly, the two species groups were found to be independent on ordination axes, responding to different sets of environmental conditions. While stands dominated by oaks with a high snag volume were highly favoured by longhorn beetles, saproxylic and threatened syrphids were limited to open-stands with large trees and a well-developed, species rich herb layer providing the floral resources required for their reproduction. Our results suggest that, when defining criteria to identify or restore important habitats for saproxylic insect conservation, variables related to different aspects of dead wood supply should not be the only criteria taken into account. © Springer 2006