The impact of naturally-occurring, trans-placental bluetongue virus serotype-8 infection on reproductive performance in sheep.

in Veterinary Journal (2011), 187(1), 72-80

Infection with bluetongue virus serotype (BTV)-8 occurred in ruminants in 2006 in Central-Western Europe. The trans-placental passage of this virus has been demonstrated in naturally- and experimentally ... [more ▼]

Infection with bluetongue virus serotype (BTV)-8 occurred in ruminants in 2006 in Central-Western Europe. The trans-placental passage of this virus has been demonstrated in naturally- and experimentally-infected cattle and in experimentally-infected sheep. Trans-placental transmission is potentially important in the 'over-wintering' of this virus and its subsequent impact on reproductive performance. This epidemiological study was carried out on a sheep flock in Belgium that had experienced a severe outbreak of BTV-8 infection, and where the seroprevalence had increased from 1.3% to 88% between January and November 2007. In total, 476 lambs and 26 aborted fetuses from 300 ewes, lambing at four distinct time periods, were investigated between November 2007 and May 2008. The following evidence suggested that BTV-8 infection occurred in utero: (1) positive PCR results from splenic tissue from aborted fetuses (n=4); (2) fetal malformations suggestive of BTV infection (n=10); (3) positive PCR results from red blood cells in-lambs (n=7), and (4) the presence of antibody at birth in viable lambs prior to the intake of colostrum (n=9). The evidence provided by this investigation strongly suggests that trans-placental BTV-8 infection occurs in naturally-infected sheep and the impact of infection on the reproductive performance of such a naive flock was considerable, with up to 25% of ewes aborting and with flock fertility reduced by 50%. The contribution of in utero-infected lambs to the over-wintering of BTV appears limited. [less ▲]

Calculating and Reporting Managed Honey Bee Colony Losses

in Yoder, Jay (Ed.) Honey Bee Colony Health (2011)

Potential of Tuta absoluta to infest potatoes (Solanum tuberosum) in Belgium.

Poster (2011)

Les phéromones d'alarme dans le règne animal

in Entomologie Faunistique = Faunistic Entomology (2011), 63(4), 259-274

Many animals respond to predation by releasing alarm signals that warn other individuals of the presence of danger in order to reduce the success of predators. While alarm signals may be visual or ... [more ▼]

Many animals respond to predation by releasing alarm signals that warn other individuals of the presence of danger in order to reduce the success of predators. While alarm signals may be visual or auditory as well as chemical, alarm pheromones are common, especially among insects and aquatic organisms. In this paper we discuss our current understanding of chemical alarm signaling in a variety of animal groups (including social and pre-social insects, marine invertebrates, fish, and mammals). We also briefly discuss the exploitation of alarm pheromones as foraging cues for natural enemies. [less ▲]

Recensement des Silphidae dans les collections d'étudiants de Gembloux Agro-Bio Tech sur la période 2001-2010

in Faunistic Entomology - Entomologie Faunistique (2011), 64(1), 15-21

Les Silphidae capturés par les étudiants de Gembloux Agro-Bio Tech (Université de Liège) durant la période 2001-2010 se répartissent entre treize espèces de Silphinae et de Nicrophorinae. Cinq espèces de ... [more ▼]

Les Silphidae capturés par les étudiants de Gembloux Agro-Bio Tech (Université de Liège) durant la période 2001-2010 se répartissent entre treize espèces de Silphinae et de Nicrophorinae. Cinq espèces de Nicrophorinae ont été recensées: Nicrophorus vespillo L. 1758, Nicrophorus vespilloides Herbst 1783, Nicrophorus interruptus Stephens 1830, Nicrophorus investigator Zetterstedt 1824, et Nicrophorus humator Gleditsch 1767. Concernant les Silphinae, on a recensé huit espèces: Oiceoptoma thoracicum L. 1758, Dendroxena quadrimaculata Scopoli 1772, Necrodes littoralis L. 1758, Ablattaria laevigata laevigata F. 1775, Thanatophilus sinuatus F. 1775, Silpha carinata Herbst 1783, Silpha tristis Illiger 1798 et Phosphuga atrata atrata L. 1758. L’espèce de Silphinae la plus représentée parmi les collections d’étudiants est P. atrata atrata suivie d’O. thoracicum. Parmi les Nicrophorus spp., N. vespilloides, N. humator et N. vespillo sont les espèces plus représentées. [less ▲]

Does Tribolium brevicornis cuticular chemistry deter cannibalism and predation of pupae?

in Journal of Insect Science [=JIS] (2011), 11

The cuticular hydrocarbons of insects are species-specific and often function as semiochemicals. The activity of Tribolium brevicornis cuticular hydrocarbons as feeding deterrents that ostensibly function ... [more ▼]

The cuticular hydrocarbons of insects are species-specific and often function as semiochemicals. The activity of Tribolium brevicornis cuticular hydrocarbons as feeding deterrents that ostensibly function to prevent pupal cannibalism and predation was evaluated. The cuticular hydrocarbons of T. brevicornis pupae were characterized and flour disk bioassays conducted with individual and combined extract components incorporated into artificial diets on which Tribolium adults fed for six days. Feeding by T. brevicornis and T. castaneum on flour disks containing cuticular extracts of T. brevicornis pupae resulted in reduced consumption and weight loss relative to feeding on control flour disks. In both cases, feeding deterrence indices exceeded 80% suggesting that T. brevicornis cuticular hydrocarbons could function to deter cannibalism and predation of pupae by larvae and adult beetles. Sixteen different cuticular hydrocarbons were identified in T. brevicornis pupal extracts. Eight of the commercially available linear alkanes were tested individually in feeding trials with eight Tribolium species. One compound (C28) significantly reduced the amount of food consumed by three species compared to control disks, whereas the compounds C25, C26, and C27elicited increased feeding in some species. Four other compounds had no effect on consumption for any species. When four hydrocarbon mixtures were tested for synergistic deterrence on T. brevicornis and T. castaneum, none significantly influenced consumption. Our results indicate that the cuticular chemistry of T. brevicornis pupae could serve to deter predation by conspecific and congeneric beetles. [less ▲]

Purification of a new fungal mannose-specific lectin from Penicillium chrysogenum and its aphicidal properties

in Fungal Biology (2011)

Placenta-Like Structure of the Aphid Endoparasitic Wasp Aphidius ervi: A Strategy of Optimal Resources Acquisition.

in PloS one (2011), 6(4), 18847

Aphidius ervi (Hymenoptera: Braconidae) is an entomophagous parasitoid known to be an effective parasitoid of several aphid species of economic importance. A reduction of its production cost during mass ... [more ▼]

Aphidius ervi (Hymenoptera: Braconidae) is an entomophagous parasitoid known to be an effective parasitoid of several aphid species of economic importance. A reduction of its production cost during mass rearing for inundative release is needed to improve its use in biological control of pests. In these contexts, a careful analysis of its entire development phases within its host is needed. This paper shows that this parasitoid has some characteristics in its embryological development rather complex and different from most other reported insects, which can be phylogenetically very close. First, its yolkless egg allows a high fecundity of the female but force them to hatch from the egg shell rapidly to the host hemocoel. An early cellularisation allowing a rapid differentiation of a serosa membrane seems to confirm this hypothesis. The serosa wraps the developing embryo until the first instar larva stage and invades the host tissues by microvilli projections and form a placenta like structure able to divert host resources and allowing nutrition and respiration of embryo. Such interspecific invasion, at the cellular level, recalls mammal's trophoblasts that anchors maternal uterine wall and underlines the high adaptation of A. ervi to develop in the host body. [less ▲]

Occurrence de la coccinelle asiatique (Harmonia axyridis Pallas), espèce invasive, dans les agro-habitats en 2009

in Entomologie Faunistique = Faunistic Entomology (2010), 63(4), 251-258

La lutte contre les pucerons de manière biologique consiste entre autre à utiliser des insectes prédateurs de pucerons tels que les coccinelles. En Belgique un des auxiliaires le plus utilisé est la ... [more ▼]

La lutte contre les pucerons de manière biologique consiste entre autre à utiliser des insectes prédateurs de pucerons tels que les coccinelles. En Belgique un des auxiliaires le plus utilisé est la coccinelle à deux points (Adalia bipunctata) mais en 1997, les horticulteurs ont introduit la coccinelle asiatique (Harmonia axyridis) afin de lutter plus efficacement contre les pucerons. Cette coccinelle invasive s'est rapidement répandue dans toute la Belgique et à travers l'Europe. Afin d'évaluer son impact sur l'entomofaune des milieux agricoles, nous avons réalisé un inventaire des aphidiphages présent sur 10 sites réparti en Wallonie. Deux méthodes d'échantillonnage ont été utilisées: (1) l'utilisation de pièges collant et (2) l'observation visuelle dans des quadras d'1m². Après 10 semaines d'inventaire, nous pouvons conclure que pour l'année 2009, la coccinelle asiatique est la coccinelle la plus abondante dans les agro-écosystèmes wallons. Les cultures préférentielles dans lesquelles la coccinelle invasive a été la plus abondante sont la pomme de terre biologique et le maïs. Culture où la quantité de puceron n'est pas forcement la plus élevée. La période de reproduction de la coccinelle asiatique se situe à la mi-juillet, période d'abondance de proies dans les cultures étudiées. [less ▲]

Bio-systématique des moustiques (Diptera : Culicidae) dans et aux alentours des fermes d’élevage en Belgique

Conference (2010, November 06)