Search results for "Trophic Interactions"
showing 10 items of 42 documents
Attraction of egg-killing parasitoids toward induced plant volatiles in a multi-herbivore context
2015
In response to insect herbivory, plants emit volatile organic compounds which may act as indirect plant defenses by attracting natural enemies of the attacking herbivore. In nature, plants are often attacked by multiple herbivores, but the majority of studies which have investigated indirect plant defenses to date have focused on the recruitment of different parasitoid species in a single-herbivore context. Here, we report our investigation on the attraction of egg parasitoids of lepidopteran hosts (Trichogramma brassicae and T. evanescens) toward plant volatiles induced by different insect herbivores in olfactometer bioassays. We used a system consisting of a native crucifer, Brassica nigr…
Integrating natural enemies and semiochemicals in cultural control for an effective IPM
2012
Since their discovery, many semiochemicals (behavior modifying chemicals) have been identified and synthetized, and a number of techniques have been developed to use them in integrated pest management (IPM) programs against insect pests. In particular, the uses of semiochemicals in IPM to monitor insect pest populations and to interfere with their behavior preventing agricultural damage are widely adopted by the growers. In the same time, evidences that semiochemicals can also modify the behavior of insect natural enemies inspired researchers to explore the possibility to use semiochemicals to conserve and/or enhance the efficacy of natural enemies in cropping systems. However the use of se…
Morphological Similarity and Ecological Overlap in Two Rotifer Species
2013
Co-occurrence of cryptic species raises theoretically relevant questions regarding their coexistence and ecological similarity. Given their great morphological similitude and close phylogenetic relationship (i.e., niche retention), these species will have similar ecological requirements and are expected to have strong competitive interactions. This raises the problem of finding the mechanisms that may explain the coexistence of cryptic species and challenges the conventional view of coexistence based on niche differentiation. The cryptic species complex of the rotifer Brachionus plicatilis is an excellent model to study these questions and to test hypotheses regarding ecological differentia…
Effect of the host plant on the immunity of a phytophagous insect : influence of grape variety on the ability of the European grapevine moth to defen…
2013
In tritrophic interactions involving phytophagous insects, host plants and natural enemies, trophic levels are highly dependent on each other. Host plant may strongly affect directly phytophagous insect and indirectly natural enemies growing on these phytophagous insects. When a natural enemy attacks a phytophagous insect, the host immune system constitutes the last chance for the host to survive to an infection. A great variation of insect immune system is generally found in populations for susceptibility to pathogens, suggesting that variable selection pressures may have shaped and driven adaptation of immune traits. This project aims to determine the influence of both host plant and natu…
Ecological role of mycotoxins in wheat crop residues and consequences on the multitrophic interactions in the soil and further development of Fusariu…
2009
Format du poster : 21 X 29,7; absent
Should grape moth larval immunity help explaining resistance against natural enemies?
2011
National audience; In tritrophic systems (plants, phytophagous insects and natural enemies), host plant variation often keys the relative performance of both the herbivore and its associated natural enemies. In bottom-up effects, host plants could affect the fitness of phytophagous insects including growth rate and adult fertility. These effects are indirectly reflected in parasitoids whose success depends on their host quality. For instance, nutrient deficiency or/and toxic defensive compounds of the plants could slow-down the development of herbivorous insects, thus extending the window of vulnerability of attacks by natural enemies. The immune system is arguably the most common resistanc…
Stable isotopes in monitoring terrestrial arthropods
2022
Monitoring of arthropods focuses typically on changes in population and range size over time. Yet, there are a myriad of other aspects that could and should be monitored under the ongoing global and local environmental change. Stable isotope analysis, widely employed in short-term ecological studies, has potential in long-term monitoring of arthropods. Here we discuss the use of stable isotopes in monitoring terrestrial arthropods, provide some empirical examples of the use of bulk tissue samples in stable isotope analysis, and outline future directions in using compound-specific stable isotope analysis in monitoring. We performed a literature search for 2012–2021 to see if stable isotopes …
The impact of wildlife and environmental factors on hantavirus infection in the host and its translation into human risk
2023
Identifying factors that drive infection dynamics in reservoir host populations is essential in understanding human risk from wildlife-originated zoonoses. We studied zoonotic Puumala orthohantavirus (PUUV) in the host, the bank vole ( Myodes glareolus ), populations in relation to the host population, rodent and predator community and environment-related factors and whether these processes are translated into human infection incidence. We used 5-year rodent trapping and bank vole PUUV serology data collected from 30 sites located in 24 municipalities in Finland. We found that PUUV seroprevalence in the host was negatively associated with the abundance of red foxes, but this process did no…
Data from: Symbiotic polydnavirus and venom reveal parasitoid to its hyperparasitoids
2018
Symbiotic relationships may provide organisms with key innovations that aid in the establishment of new niches. For example, during oviposition, some species of parasitoid wasps, whose larvae develop inside the bodies of other insects, inject polydnaviruses into their hosts. These symbiotic viruses disrupt host immune responses, allowing the parasitoid’s progeny to survive. Here, we show that symbiotic polydnaviruses also have a downside to the parasitoid’s progeny by initiating a multi-trophic chain of interactions that reveals the parasitoid larvae to their enemies. These enemies are hyperparasitoids that use the parasitoid progeny as host for their own offspring. We found that the virus …
Egg parasitoid attraction toward induced plant volatiles is disrupted by a non-host herbivore attacking above or belowground plant organs.
2014
Plants respond to insect oviposition by emission of oviposition-induced plant volatiles (OIPVs) which can recruit egg parasitoids of the attacking herbivore. To date, studies demonstrating egg parasitoid attraction to OIPVs have been carried out in tritrophic systems consisting of one species each of plant, herbivore host, and the associated egg parasitoid. Less attention has been given to plants experiencing multiple attacks by host and non-host herbivores that potentially could interfere with the recruitment of egg parasitoids as a result of modifications to the OIPV blend. Egg parasitoid attraction could also be influenced by the temporal dynamics of multiple infestations, when the same …