Background: Modern agriculture has undoubtedly led to increasing wildlife-human conflicts, notably concerning bird damage in productive and attractive crops during some parts of the annual cycle. This issue requires utmost attention for sedentary birds that may impact agricultural crops at any stage of their annual life cycle. Reducing bird-human conflicts requires a better understanding of the relationship between bird foraging activity and the characteristics of agricultural areas, notably with respect to changes in food-resource availability and crop sensitivity across the year.
View Article and Find Full Text PDFBackground: The Biological Field Station of Paimpont (Station Biologique de Paimpont, SBP), owned by the University of Rennes and located in the Brocéliande Forest of Brittany (France), has been hosting student scientific research and field trips during the last 60 years. The study area of the SBP is a landscape mosaic of 17 ha composed of gorse moors, forests, prairies, ponds and creeks. Land use has evolved over time.
View Article and Find Full Text PDFThe "push-pull" strategy aims at manipulating insect pest behavior using a combination of attractive and repulsive stimuli using either plants derived volatile organic compounds or insect host plant preferences. In a field experiment using broccoli as a crop, we combined in a "push-pull" context the oviposition deterrent effect of dimethyl disulfide and the attractive effect of a Chinese cabbage strip enhanced with Z-3-hexenyl-acetate. The push component dimethyl disulfide reduced Delia radicum L.
View Article and Find Full Text PDFVolatile Organic Compounds (VOCs) released by plants are involved in various orientation processes of herbivorous insects and consequently play a crucial role in their reproductive success. In the context of developing new strategies for crop protection, several studies have previously demonstrated the possibility to limit insect density on crops using either host or non-host plants that release attractive or repellent VOCs, respectively. The cabbage root fly, Delia radicum, is an important pest of brassicaceous crops for which control methods have to be implemented.
View Article and Find Full Text PDFThe aim of this study was to investigate the influence of volatile compounds from four secondary host plants on the ability of Dinarmus basalis Rond. (Hymenoptera: Pteromalidae) to locate, recognize, and parasitize its host, 4(th)instar larvae or pupae of Callosobruchus maculatus F. (Coleoptera: Chrysomelidae).
View Article and Find Full Text PDFInduced plant defence in response to phytophagous insects is a well described phenomenon. However, so far little is known about the effect of induced plant responses on subsequently colonizing herbivores in the field. Broccoli plants were induced in the belowground compartment using (i) infestation by the root-herbivore Delia radicum, (ii) root application of jasmonic acid (JA) or (iii) root application of salicylic acid (SA).
View Article and Find Full Text PDFIn the study of plant defense evolution, invasive plant species can be very insightful because they are often introduced without their enemies, and traits linked to defense can be released from selective pressures and evolve. Further, studying plant defense evolution in invasive species is important for biological control and use of these species. In this study, we investigated the evolution of the defensive chemicals quinolizidine alkaloids (QAs) in the invasive species gorse, Ulex europaeus.
View Article and Find Full Text PDFInduced responses to insect herbivory are a common phenomenon in the plant kingdom. So far, induced responses have mostly investigated in aerial plant parts. Recently it was found that root herbivore may also elicit both local and systemic responses affecting aboveground herbivores and their natural enemies.
View Article and Find Full Text PDFIn 2009, the genome of the pea aphid (Acyrthosiphon pisum) was sequenced and partially annotated. This means that the scientific community has now access to the genetic material of aphids that are serious pests of plants. The description of an aphid genome is a first step to go deeper in the understanding of the biology of these insects.
View Article and Find Full Text PDFFluid flow into and out of the stylets of xylem-ingesting sharpshooters (Hemiptera: Cicadellidae: Cicadellinae) is powered by muscles of the cibarial pump. Such fluid flow is crucial for transmission of Xylella fastidiosa, the Pierce's Disease bacterium, yet has not been rigorously studied via electrical penetration graph (EPG) technology. We correlated EPG waveforms with electromyographically (EMG) recorded muscle potentials from the cibarial dilator muscles, which power the piston-like cibarial diaphragm.
View Article and Find Full Text PDFThe type (antixenosis or antibiosis) of resistance against the aphids Myzus persicae (Sulzer) and Macrosiphum euphorbiae (Thomas) was characterized for the wild tuber-bearing potatoes, Solanum chomatophilum Bitter and Solanum stoloniferum Schltdl. & Bouché through behavioral (olfactometry and electrical penetration graph) and physiological studies. In dual-choice assays, only S.
View Article and Find Full Text PDFDimethyl disulfide (DMDS) was identified as a major volatile constituent of Brassica napus roots heavily infested by Delia radicum, the cabbage root fly. Attractiveness of this widespread compound was tested in the field in a naturally complex odorous environment. By using an original setup especially designed for ground dwelling beetles, different concentrations of the pure molecule as well as attractiveness of the natural blend emitted by the rotten part of infested roots were tested simultaneously.
View Article and Find Full Text PDFTo defend themselves against herbivory, plants use a variety of direct and indirect strategies involving induced increases in secondary substances. Species of the Allium genus (Alliaceae), such as the leek Allium porrum (L.), produce nonprotein sulfur amino acids derived from cysteine, i.
View Article and Find Full Text PDFThe plant-derived insecticides have introduced a new concept in insecticide research. In response to insect attacks, some plants can release volatile sulfur compounds such as dimethyl disulfide (DMDS) in the atmosphere, which are lethal for the generalist insects. We demonstrate that DMDS induced an uncommon complex neurotoxic activity.
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