354 research outputs found

    Hyperparasitoids exploit herbivore-induced plant volatiles during host location to assess host quality and non-host identity

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    Although consumers often rely on chemical information to optimize their foraging strategies, it is poorly understood how top carnivores above the third trophic level find resources in heterogeneous environments. Hyperparasitoids are a common group of organisms in the fourth trophic level that lay their eggs in or on the body of other parasitoid hosts. Such top carnivores use herbivore-induced plant volatiles (HIPVs) to find caterpillars containing parasitoid host larvae. Hyperparasitoids forage in complex environments where hosts of different quality may be present alongside non-host parasitoid species, each of which can develop in multiple herbivore species. Because both the identity of the herbivore species and its parasitization status can affect the composition of HIPV emission, hyperparasitoids encounter considerable variation in HIPVs during host location. Here, we combined laboratory and field experiments to investigate the role of HIPVs in host selection of hyperparasitoids that search for hosts in a multi-parasitoid multi-herbivore context. In a wild Brassica oleracea-based food web, the hyperparasitoid Lysibia nana preferred HIPVs emitted in response to caterpillars parasitized by the gregarious host Cotesia glomerata over the non-host Hyposoter ebeninus. However, no plant-mediated discrimination occurred between the solitary host C. rubecula and the non-host H. ebeninus. Under both laboratory and field conditions, hyperparasitoid responses were not affected by the herbivore species (Pieris brassicae or P. rapae) in which the three primary parasitoid species developed. Our study shows that HIPVs are an important source of information within multitrophic interaction networks allowing hyperparasitoids to find their preferred hosts in heterogeneous environments

    Waterreservoirs op bedrijfsniveau alternatief voor zoetwatervoorziening landbouw?

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    De zoetwatervoorziening van de landbouw in Nederland staat hoog op de beleidsagenda. Het Rijk verbreedt het zoeken naar oplossingen voor het zoetwatervraagstuk van alleen kijken naar aanbod vanuit het hoofdwatersysteem naar ook het verkennen van de mogelijkheden voor grotere zelfvoorzienendheid. De vraag, die in dit artikel wordt behandeld, is of vasthouden van het neerslagoverschot in zoetwaterbekkens op bedrijfsniveau een redelijk alternatief vormt voor wateraanvoe

    Successful Tocilizumab Treatment for Scleritis

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    Purpose: To present a rare case of scleritis associated with a prior diagnosis of giant cell arteritis (GCA) that was unresponsive to glucocorticoids, nonsteroidal anti-inflammatory drugs (NSAIDs), methotrexate, and azathioprine, but reached and maintained a full remission with tocilizumab. Observations: A 62-year-old Caucasian female presented with scleritis and headache. Four years earlier, the patient was diagnosed with GCA. Treatment with topical and systemic NSAIDs, prednisone and diverse disease-modifying antirheumatic drugsonly had a partial effect on the scleritis whilst the arthralgia and headaches increased. Despite the absence of laboratory evidence of active GCA, tocilizumab was started and the scleritis and headaches disappeared within several days. Prednisone could be fully tapered within 3 months and to date, 12 months after the start of tocilizumab, the patient has maintained a sustained remission. Conclusions: Our patient demonstrates that tocilizumab might represent a therapeutic option for scleritis, and its further evaluation for this severe ocular disease is worthwhile

    Exploiting chemical ecology to manage hyperparasitoids in biological control of arthropod pests

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    Insect hyperparasitoids are fourth trophic level organisms that commonly occur in terrestrial food webs, yet they are relatively understudied. These top-carnivores can disrupt biological pest control by suppressing the populations of their parasitoid hosts, leading to pest outbreaks, especially in confined environments such as greenhouses where augmentative biological control is used. There is no effective eco-friendly strategy that can be used to control hyperparasitoids. Recent advances in the chemical ecology of hyperparasitoid foraging behavior have opened opportunities for manipulating these top-carnivores in such a way that biological pest control becomes more efficient. We propose various infochemical-based strategies to manage hyperparasitoids. We suggest that a push-pull strategy could be a promising approach to ‘push’ hyperparasitoids away from their parasitoid hosts and ‘pull’ them into traps. Additionally, we discuss how infochemicals can be used to develop innovative tools improving biological pest control (i) to restrict accessibility of resources (e.g. sugars and alternative hosts) to primary parasitoid only or (ii) to monitor hyperparasitoid presence in the crop for early detection. We also identify important missing information in order to control hyperparasitoids and outline what research is needed to reach this goal. Testing the efficacy of synthetic infochemicals in confined environments is a crucial step towards the implementation of chemical ecology-based approaches targeting hyperparasitoids. © 2019 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry

    Parasitic wasp-associated symbiont affects plant-mediated species interactions between herbivores

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    Microbial mutualistic symbiosis is increasingly recognised as a hidden driving force in the ecology of plant–insect interactions. Although plant-associated and herbivore-associated symbionts clearly affect interactions between plants and herbivores, the effects of symbionts associated with higher trophic levels has been largely overlooked. At the third-trophic level, parasitic wasps are a common group of insects that can inject symbiotic viruses (polydnaviruses) and venom into their herbivorous hosts to support parasitoid offspring development. Here, we show that such third-trophic level symbionts act in combination with venom to affect plant-mediated interactions by reducing colonisation of subsequent herbivore species. This ecological effect correlated with changes induced by polydnaviruses and venom in caterpillar salivary glands and in plant defence responses to herbivory. Because thousands of parasitoid species are associated with mutualistic symbiotic viruses in an intimate, specific relationship, our findings may represent a novel and widespread ecological phenomenon in plant–insect interactions

    Water and ammonia abundances in S140 with the Odin satellite

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    We have used the Odin satellite to obtain strip maps of the ground-state rotational transitions of ortho-water and ortho-ammonia, as well as CO(5-4) and 13CO(5-4) across the PDR, and H218O in the central position. A physi-chemical inhomogeneous PDR model was used to compute the temperature and abundance distributions for water, ammonia and CO. A multi-zone escape probability method then calculated the level populations and intensity distributions. These results are compared to a homogeneous model computed with an enhanced version of the RADEX code. H2O, NH3 and 13CO show emission from an extended PDR with a narrow line width of ~3 kms. Like CO, the water line profile is dominated by outflow emission, however, mainly in the red wing. The PDR model suggests that the water emission mainly arises from the surfaces of optically thick, high density clumps with n(H2)>10^6 cm^-3 and a clump water abundance, with respect to H2, of 5x10^-8. The mean water abundance in the PDR is 5x10^-9, and between ~2x10^-8 -- 2x10^-7 in the outflow derived from a simple two-level approximation. Ammonia is also observed in the extended clumpy PDR, likely from the same high density and warm clumps as water. The average ammonia abundance is about the same as for water: 4x10^-9 and 8x10^-9 given by the PDR model and RADEX, respectively. The similarity of water and ammonia PDR emission is also seen in the almost identical line profiles observed close to the bright rim. Around the central position, ammonia also shows some outflow emission although weaker than water in the red wing. Predictions of the H2O(110-101) and (111-000) antenna temperatures across the PDR are estimated with our PDR model for the forthcoming observations with the Herschel Space Observatory.Comment: 13 pages, 14 figures, 10 tables. Accepted for publication in Astronomy & Astrophysics 14 November 200

    Kweek van yellowtail kingfish (Seriola lalandi) in Nederland

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    In een studie volgens het 'Fork to Farm' principe is de yellowtail kingfish (Seriola lalandi) als potentieel succesvolle soort voor de Nederlandse aquacultuursector aangewezen. Dit artikel beschrijft de eerste resultaten van het onderzoek door Imares naar de teelt van deze soort in Nederlandse recirculatiesystemen

    De samenstelling van discards in de pelagische visserij voor valorisatie doeleinden

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    Vanaf januari 2015 wordt de discard regelgeving vanuit de EU aangepast, dit betekent dat de sector zich moet committeren aan deze regelgeving. Hierdoor zullen de bijvangsten die op dit moment nog overboord gaan, aangeland moeten worden. Er is een traject ingezet om de kansen tot valorisatie van de bijvangsten te ontwikkelen

    Water vasthouden aan de bron: inzicht door modelberekeningen

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    De meest effectieve strategie voor de reductie van piekafvoeren, water vasthouden, is bergen van water bij de bron, waarbij de afstroming van water op perceelsniveau wordt bemoeilijkt. Om een onderbouwd inzicht in effect en relevantie van water vasthouden te krijgen zijn, in samenspraak met betrokken instanties, vijf maatregelen met behulp van de computercode SIMGRO geëvalueerd in de stroomgebieden Peelsche Loop, Groote Wetering en Raamsloop. Piekafvoeren kunnen met 3 tot 45% worden gereduceerd. De meest effectieve manier om water vast te houden is het voorkómen van maaiveldafvoer waarbij water tijdelijk op het maaiveld wordt geborgen, met als neveneffect structurele grondwaterstandverhogingen en effecten op de landbouw. Minder effectieve maatregelen hebben een marginaal effect op de regionale hydrologie. Inundaties verdwijnen sneller met goede drainage

    Smartphone Apps for Measuring Human Health and Climate Change Co-Benefits: A Comparison and Quality Rating of Available Apps.

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    BACKGROUND: Climate change and the burden of noncommunicable diseases are major global challenges. Opportunities exist to investigate health and climate change co-benefits through a shift from motorized to active transport (walking and cycling) and a shift in dietary patterns away from a globalized diet to reduced consumption of meat and energy dense foods. Given the ubiquitous use and proliferation of smartphone apps, an opportunity exists to use this technology to capture individual travel and dietary behavior and the associated impact on the environment and health. OBJECTIVE: The objective of the study is to identify, describe the features, and rate the quality of existing smartphone apps which capture personal travel and dietary behavior and simultaneously estimate the carbon cost and potential health consequences of these actions. METHODS: The Google Play and Apple App Stores were searched between October 19 and November 6, 2015, and a secondary Google search using the apps filter was conducted between August 8 and September 18, 2016. Eligible apps were required to estimate the carbon cost of personal behaviors with the potential to include features to maximize health outcomes. The quality of included apps was assessed by 2 researchers using the Mobile Application Rating Scale (MARS). RESULTS: Out of 7213 results, 40 apps were identified and rated. Multiple travel-related apps were identified, however no apps solely focused on the carbon impact or health consequences of dietary behavior. None of the rated apps provided sufficient information on the health consequences of travel and dietary behavior. Some apps included features to maximize participant engagement and encourage behavior change towards reduced greenhouse gas emissions. Most apps were rated as acceptable quality as determined by the MARS; 1 was of poor quality and 10 apps were of good quality. Interrater reliability of the 2 evaluators was excellent (ICC=0.94, 95% CI 0.87-0.97). CONCLUSIONS: Existing apps capturing travel and dietary behavior and the associated health and environmental impact are of mixed quality. Most apps do not include all desirable features or provide sufficient health information. Further research is needed to determine the potential of smartphone apps to evoke behavior change resulting in climate change and health co-benefits
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