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The invasion of Europe by the western corn rootworm, North America's most destructive corn pest, is ongoing and represents a serious threat to European agriculture. Because this pest was initially introduced in Central Europe, it was believed that subsequent outbreaks in Western Europe originated from this area. Using model-based Bayesian analyses of the(More)
Many plant-feeding insect species considered to be polyphagous are in fact composed of genetically differentiated sympatric populations that use different hosts and between which gene flow still exists. We studied the population genetic structure of the cotton-melon aphid Aphis gossypii that is considered as one of the most polyphagous aphid species. We(More)
1. Although parasitoids are used widely as a biological models for understanding the evolution of animal behaviour, most studies have been constrained to the laboratory. The dearth of field studies has been compounded by the almost complete ignorance of the physiological parameters involved in foraging and dispersal, in particular of the energetic(More)
Intensive chemical treatments have led to the development of a number of insecticide resistance mechanisms in the peach-potato aphid Myzus persicae (Sulzer). Some of these mechanisms are known to be associated with negative pleiotropic effects (resistance costs). Molecular and biochemical methods were used to determine the genotypes or phenotypes associated(More)
In agrosystems, pests are submitted to strong human-imposed selective pressures to which they sometimes adapt rapidly, either through selection of genotypes resulting from mutation and ⁄ or recombination events, or through phenotypic plasticity. Understanding how insects respond to such selective pressures is of great importance for sustainable pest(More)
In the solitary parasitoid wasp Venturia canescens both arrhenotokously (sexual) and thelytokously (parthenogenetical) reproducing individuals occur sympatrically. We found in the laboratory that thelytokous wasps are able to mate, receive and use sperm of arrhenotokous males. Using nuclear (amplified fragment length polymorphism, virus-like protein) and(More)
We compared 18 Aedes aegypti strains for oral susceptibility to dengue virus type 2 (DEN-2) using a feeding protocol in which all parameters remained constant, including the titer of the infectious bloodmeal. For most strains, no significant variation between replicates was observed. Comparisons between pairs of strains showed variation of different(More)
The ideal free distribution (IFD) is a stable distribution of competitors among resource patches. For equally efficient competitors , equilibrium is reached when the per capita rate of intake equalizes across patches. The seminal version of the IFD assumes omniscience, but populations may still converge toward the equilibrium provided that competitors 1)(More)
Aphis gossypii is an aphid species that is found throughout the world and is extremely polyphagous. It is considered a major pest of cotton and cucurbit species. In Europe, A. gossypii is assumed to reproduce exclusively by apomictic parthenogenesis. The present study investigates the genetic diversity of A. gossypii in a microgeographic, fragmented habitat(More)