References of "Frere, Isabelle"
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See detailOptimisation of a semiochemical slow-release alginate formulation attractive towards Aphidius ervi Haliday parasitoids
Heuskin, Stéphanie ULg; Lorge, Stéphanie; Godin, Bruno et al

in Pest Management Science (2011)

BACKGROUND: Optimisation of alginate formulations is described in order to develop semiochemical (E-β-farnesene and E-β-caryophyllene) slow-release devices in biological control approaches by attracting ... [more ▼]

BACKGROUND: Optimisation of alginate formulations is described in order to develop semiochemical (E-β-farnesene and E-β-caryophyllene) slow-release devices in biological control approaches by attracting predators and parasitoids of aphids. Various formulation criteria were optimised with respect to semiochemical encapsulation capacity. Moreover, the optimised formulation was characterised by texturometry and confocal microscopy. The slow-release rates of semiochemicals were calculated in laboratory controlled conditions. The attractiveness of semiochemical formulations towards Aphidius ervi was demonstrated by olfactometry. RESULTS: Two major parameters were highlighted in encapsulation optimisation: the type of alginate (Sigma L) and the type of crosslinker ion (Ca2+). Other formulation parameters were optimised: ionic strength (0.5M), Ca2+ (0.2 M) and alginate (1.5%) concentrations and the maturation time of beads in CaCl2 solution (48 h). After physical characterisation of beads, semiochemical slow-release measurements showed that alginate formulations were efficient sesquiterpene releasers, with 503 μg of E-β-farnesene and 1791 μg of E-β-caryophyllene totally released in 35 days. The efficiency of semiochemical alginate beads as attractants for female parasitoids was demonstrated, with high percentages of attraction for semiochemical odours (88 and 90% for E-β-farnesene and E-β-caryophyllene respectively) and significant statistical results. CONCLUSION: Semiochemical alginate beads can be considered as efficient slow-release systems in biological control. These formulations could be very useful to attract aphid parasitoids on crop fields. [less ▲]

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See detailPlacenta-Like Structure of the Aphid Endoparasitic Wasp Aphidius ervi: A Strategy of Optimal Resources Acquisition.
Sabri, Ahmed ULg; Hance, Thierry; Leroy, Pascal ULg et al

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 ▲]

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See detailInvolvement of odorant cues in the process of superparasitism avoidance
Vandermoten, Sophie ULg; Frere, Isabelle; Hance, Thierry et al

Poster (2010, August)

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See detailInvolvement of odorant cues in the process of superparasitism avoidance
Verheggen, François ULg; Vandermoten, Sophie ULg; Frere, Isabelle et al

Poster (2010, August)

The ability to avoid superparasitism provides a selective advantage to parasitoid females, allowing them to avoid depositing eggs in lower quality host. We observed in a Y-olfactometer that generalist ... [more ▼]

The ability to avoid superparasitism provides a selective advantage to parasitoid females, allowing them to avoid depositing eggs in lower quality host. We observed in a Y-olfactometer that generalist aphid parasitoids, Aphidius ervi and Aphidius rhopalosiphi (Hymenoptera, Braconidae), were more attracted toward non-parasitized than parasitized Sitobion avenae (Hemiptera, Aphididae) colonies. We collected the odors released from healthy aphids and aphids parasitized for 2 and 6 days using an electronic nose. Sitobion avenae alarm pheromone, (E)-ß-farnesene (EßF), was the only chemical identified, and was found in lower quantities in parasitized aphids. Both parasitoid species provided pronounced electrical depolarizations to EßF in electroantennography (EAG), and both were attracted to the latter compound in the Y-olfactometer. Parasitoid attraction was known to be guided by a variety of odorant cues released by plants and hosts, and our results support the hypothesis that the aphid alarm pheromone acts as a kairomone for A. ervi and A. rhopalosiphi. [less ▲]

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See detailParticularities of Aphidius ervi embryo development and main limitations of its in vitro culture
Sabri, Ahmed ULg; Leroy, Pascal ULg; Hance, Thierry et al

Poster (2010, May 05)

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See detailIsolation, pure culture and characterization of Serratia symbiotica, the R-type of secondary endosymbionts of the black bean aphid Aphis fabae.
Sabri, Ahmed ULg; Leroy, Pascal ULg; Haubruge, Eric ULg et al

in International Journal of Systematic and Evolutionary Microbiology (2010)

An intracellular symbiotic bacterium was isolated from the flora of a natural clone of the black bean aphid Aphis fabae. The strain was able to grow freely in aerobic condition on a rich medium containing ... [more ▼]

An intracellular symbiotic bacterium was isolated from the flora of a natural clone of the black bean aphid Aphis fabae. The strain was able to grow freely in aerobic condition on a rich medium containing 1% of each of following substrates; dextrose, yeast extract and peptone of casein. Pure culture was achieved through the use of solid-phase culture on the same medium and was designated CWBI-2.3T. 16S ribosomal DNA sequence analysis revealed that CWBI-2.3T strain was a member of the gamma-3 subgroup of the class Proteobacteria, having high sequence identity (>99%) with the R-Type of secondary endosymbiont found in several aphid species Serratia symbiotica. As strain CWBI-2.3T (=LMG 25624T =DSM 23270T) was the first R-type symbiont to be isolated and characterized, we proposed to designate it as the type strain of Serratia symbiotica species. [less ▲]

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