Search results for "Parasitoids"
showing 10 items of 36 documents
Genetic variation in the behavioural mechanisms involved in the response of the egg parasitoid Trissolcus brochymenae to contact chemical cues left b…
2021
International audience; 1. The ability of parasitoid females to perceive chemical traces left by theirhosts is of utmost importance in the host location process. The behaviours involved insuch ability have thus most likely been promoted by natural selection in the course ofthe evolutionary time. For this to happen, however, there must be signicant geneticvariation in natural populations on which natural selection could act.2. Using the isofemale line method and motion analysis, we detected signicantintra-population genetic variation for several walking behaviour traits of the eggparasitoid Trissolcus brochymenae (Hymenoptera: Scelionidae) females responding tochemical traces left by its h…
Biological protection against grape berry moths. A review
2018
International audience; Grape is a major crop, covering 7.5 M ha worldwide, that is currently being confronted with three main challenges: intensive pesticide use that must be reduced, invasion by new pests/diseases, and climate change. The biological control of pests and vectors would help address these challenges. Here, we review the scientific literature on the biological control of grape moths by macroorganisms (excluding nematodes). Two components, biological control with an active human role, mainly using biocontrol agents through inundation or inoculation, and conservation biological control, are considered. The major points are the following. (1) Tortricid grape moths seriously dama…
Plant surfaces of vegetable crops mediate interactions between chemical footprints of true bugs and their egg parasitoids.
2009
During the host location process, egg parasitoids can eavesdrop on chemical cues released from immature and adult hosts. These indirect host-related cues are highly detectable, but of low reliability because they lead egg parasitoid females to an area where oviposition is likely to occur rather then providing wasps with direct information on the presence of eggs and their location. In the host-parasitoid associations between true bugs and their scelionid egg parasitoids, female wasps perceive the chemical residues left by host adults walking on substrates as contact kairomones, displaying a characteristic arrestment posture. In this study, we demonstrated that epicuticular waxes of leaves o…
Disentangling higher trophic level interactions in the cabbage aphid food web using high-throughput DNA sequencing
2017
International audience; The lack of understanding of complex food-web interactions has been a major gap in the history of biological control. In particular, a better understanding of the functioning of pest food-webs and how they vary between native and invaded geographical ranges is of prime interest for biological control research and associated integrated pest management. Technical limitations associated with the deciphering of complex food-webs can now be largely overcome by the use of high throughput DNA sequencing techniques such as Illumina MiSeq. We tested the efficiency of this next generation sequencing technology in a metabarcoding approach, to study aphid food-webs using the cab…
Indagini sulle infestazioni di Aphis gossypii Glover su melone invernale (Cucumis melo Var. Helios) in aziende a conduzione biologica della Sicilia o…
2011
Investigations on the aphid infestation occurring on winter melon crops (Cucumis melo var. Helios) in organic farms of western Sicily The winter melon (Cucumis melo L.) is an important crop in Sicily. Previous studies carried out in western Sicily have shown that the aphid species Aphis gossipii is the key pest of winter melon crops.A. gossypii is a cosmopolitan species with very polyphagous habits; this phytophagous insect is capable of serious economic damage due to direct feeding of the sap plant and due to the honeydew secretion and the consequent presence of sooty mold and due to the possible transmission of viruses. The aim of this work was to investigate the levels of aphid infestati…
Influence of parasitoid-associated viral symbionts on plant–insect interactions and biological control
2021
International audience; Insect parasitoids have evolved symbiotic interactions with several viruses and thousands of parasitoid species have established mutualistic associations with polydnaviruses (PDVs). While PDVs have often been described as virulence factors allowing development of immature parasitoids inside their herbivore hosts, there is increasing awareness that PDVs can affect plant-insect interactions. We review recent literature showing that PDVs alter not only host physiology, but also feeding patterns and composition of herbivore's oral secretions. In turn PDV-induced changes in herbivore phenotype affect plant responses to herbivory with consequences ranging from differential…
Learning can be detrimental for a parasitic wasp
2021
Animals have evolved the capacity to learn, and the conventional view is that learning allows individuals to improve foraging decisions. The parasitoid Telenomus podisi has been shown to parasitize eggs of the exotic stink bug Halyomorpha halys at the same rate as eggs of its coevolved host, Podisus maculiventris, but the parasitoid cannot complete its development in the exotic species. We hypothesized that T. podisi learns to exploit cues from this non-coevolved species, thereby increasing unsuccessful parasitism rates. We conducted bioassays to compare the responses of naïve vs. experienced parasitoids on chemical footprints left by one of the two host species. Both naïve and experienced …
Structure of insect community in the fungus Inonotus radiatus in riparian boreal forests
2016
ABSTRACTBasidiomes of polypore fungi host many insects. Yet systematic information about insect assemblages from most fungal species is lacking. We studied the insect community associated with the wood-decaying fungus Inonotus radiatus (Sowerby: Fr.) P. Karst. (Hymenochaetales). More specifically, we studied the effect of successional stage and weight of basidiomes, as well as shore exposition (north or south), on species richness and composition, as well as occurrence and abundance of the most abundant fungivores. Basidiomes were collected from riparian forests at five lakes in Sweden. Insects were reared out from the basidiomes in the laboratory. A total of 5645 adult insect individuals o…
OLIVE FRUIT FLY: A threat to the South African olive industry?
2015
Olive fruit fly (Bactrocera oleae) is the most serious pest of cultivated olives in the Mediterranean basin. to date we have not seen the same level of damage in south africa, but the question remained whether it poses a similar threat as the local olive industry expands. From this study it is clear that the climatic con- ditions during the period preceding harvest are un- favourable for rapid population growth of OFF in the Western Cape, in contrast to conditions in the coastal area of Trapani province in Sicily. Climate, and not parasitism, appears to be the main factor limiting OFF population levels in the Western Cape. While sporadic outbreaks of economically damaging OFF infestations c…
Parasitoids (Hymenoptera) of leaf-spinning moths (Lepidoptera) feeding on Vaccinium uliginosum L. along an ecological gradient in central European pe…
2011
Parasitoids of leaf-spinning Lepidoptera associated with two isolated central European peat bogs were investigated. Five families of parasitoid Hymenoptera (Braconidae, lchneumonidae, Eulophidae, Pteromalidae and Encyrtidae) were recorded. Three categories were recognised: (1) primary parasitoids, (2) facultative hyperparasitoids and (3) obligatory hyperparasitoids. Ten species of Braconidae, five species and seven marked morphospecies among lchneumonidae, and three species of Chalcidoidea were identified. Despite of some niche-specific (but less host-specific) parasitoids, all these hymenopterans are likely to be generalists and none of them were confirmed to be habitat and/or host special…