Search results for "host-parasite"
showing 10 items of 355 documents
Spatiotemporal Structure of Host‐Pathogen Interactions in a Metapopulation
2009
International audience; The ecological and evolutionary dynamics of species are influenced by spatiotemporal variation in population size. Unfortunately, we are usually limited in our ability to investigate the numerical dynamics of natural populations across large spatial scales and over long periods of time. Here we combine mechanistic and statistical approaches to reconstruct continuous-time infection dynamics of an obligate fungal pathogen on the basis of discrete-time occurrence data. The pathogen, Podosphaera plantaginis, infects its host plant, Plantago lanceolata, in a metapopulation setting where the presence of the pathogen has been recorded annually for 6 years in similar to 4,00…
Cercarial behaviour alters the consumer functional response of three‐spined sticklebacks
2020
This is the peer reviewed version of the following article: Born-Torrijos, A., Paterson, R., van Beest, G., Vyhlídalová, T., Henriksen, E.H., Knudsen, R., Kristoffersen, R., Amundsen, P.-A. & Soldánová, M. (2021). Cercarial behaviour alters the consumer functional response of three-spined sticklebacks. Journal of Animal Ecology, 90, 978-988, which has been published in final form at https://doi.org/10.1111/1365-2656.13427. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Use of Self-Archived Versions. This article may not be enhanced, enriched or otherwise transformed into a derivative work, without express permission from Wiley or by st…
Impact of host nutritional status on infection dynamics and parasite virulence in a bird-malaria system.
2014
10 pages; International audience; Host resources can drive the optimal parasite exploitation strategy by offering a good or a poor environment to pathogens. Hosts living in resource-rich habitats might offer a favourable environment to developing parasites because they provide a wealth of resources. However, hosts living in resource-rich habitats might afford a higher investment into costly immune defences providing an effective barrier against infection. Understanding how parasites can adapt to hosts living in habitats of different quality is a major challenge in the light of the current human-driven environmental changes. We studied the role of nutritional resources as a source of phenoty…
Cold water reduces the severity of parasite-inflicted damage : support for wintertime recuperation in aquatic hosts
2019
The reduction in host fitness caused by parasite infections (virulence) depends on infection intensity and the degree of damage caused per parasite. Environmental conditions can shape both virulence components, but in contrast to infection intensity, environmental impacts on per-parasite damage are poorly understood. Here, we studied the effect of ambient temperature on per-parasite damage, which is jointly determined by the ability of parasites to induce harm (per-parasite pathogenicity) and the ability of hosts to limit damage (tolerance). We experimentally exposed two salmonid species, Atlantic salmon (Salmo salar) and sea trout (Salmo trutta), to replicated genotypes of the eye fluke Di…
Plant-phenotypic changes induced by parasitoid ichnoviruses enhance the performance of both unparasitized and parasitized caterpillars
2021
Early Access; International audience; There is increasing awareness that interactions between plants and insects can be mediated by microbial symbionts. Nonetheless, evidence showing that symbionts associated with organisms beyond the second trophic level affect plant-insect interactions are restricted to a few cases belonging to parasitoid-associated bracoviruses. Insect parasitoids harbor a wide array of symbionts which, like bracoviruses, can be injected into their herbivorous hosts to manipulate their physiology and behavior. Yet, the function of these symbionts in plant-based trophic webs remains largely overlooked. Here we provide the first evidence of a parasitoid-associated symbiont…
Modeling Environmental Influences in the Psyllaephagus bliteus (Hymenoptera: Encyrtidae)-Glycaspis brimblecombei (Hemiptera: Aphalaridae) Parasitoid-…
2017
Glycaspis brimblecombei Moore (Hemiptera: Aphalaridae) is an invasive psyllid introduced into the Mediterranean area, where it affects several species of Eucalyptus. Psyllaephagus bliteus Riek (Hymenoptera: Encyrtidae) is a specialized parasitoid of this psyllid that was accidentally introduced into Italy in 2011. We developed a model of this host–parasitoid system that accounts for the influence of environmental conditions on the G. brimblecombei population dynamics and P. bliteus parasitism rates in the natural ecosystem. The Lotka–Volterra-based model predicts non-constant host growth and parasitoid mortality rates in association with variation in environmental conditions. The model was …
Host-driven morphological variability in Orobanche crenata (Orobanchaceae)
2018
Studies on interactions between Orobanche species and their hosts are mainly focused on resistance, radical interactions, and haustorium development. The influence of the host plant on morphology of the parasite under environmental controlled conditions is not reported in the literature. With the aim of filling this gap, the results of cultivation experiments of Orobanche crenata on Vicia faba, V. sativa, Pisum sativum, Cicer arietinum, and Lathyrus clymenum are presented. The tested population of O. crenata infected all the studied hosts but showed preferences toward Vicia and Pisum and, in particular, toward a foreign V. sativa cv. The higher resistance of the evaluated local cv. could be…
Defense strategies used by two sympatric vineyard moth pests.
2014
8 pages; International audience; Natural enemies including parasitoids are the major biological cause of mortality among phytophagous insects. In response to parasitism, these insects have evolved a set of defenses to protect themselves, including behavioral, morphological, physiological and immunological barriers. According to life history theory, resources are partitioned to various functions including defense, implying trade-offs among defense mechanisms. In this study we characterized the relative investment in behavioral, physical and immunological defense systems in two sympatric species of Tortricidae (Eupoecilia ambiguella, Lobesia botrana) which are important grapevine moth pests. …
The response of an egg parasitoid to substrate-borne semiochemicals is affected by previous experience
2016
AbstractAnimals can adjust their behaviour according to previous experience gained during foraging. In parasitoids, experience plays a key role in host location, a hierarchical process in which air-borne and substrate-borne semiochemicals are used to find hosts. In nature, chemical traces deposited by herbivore hosts when walking on the plant are adsorbed by leaf surfaces and perceived as substrate-borne semiochemicals by parasitoids. Chemical traces left on cabbage leaves by adults of the harlequin bug (Murgantia histrionica) induce an innate arrestment response in the egg parasitoid Trissolcus brochymenae characterized by an intense searching behaviour on host-contaminated areas. Here we …
Variation and covariation in infectivity, virulence and immunodepression in the host-parasite association Gammarus pulex-Pomphorhynchus laevis.
2009
Parasites often manipulate host immunity for their own benefit, either by exacerbating or suppressing the immune response and this may directly affect the expression of parasite virulence. However, genetic variation in immunodepression, which is a prerequisite to its evolution, and the relationship between immunodepression and virulence, have rarely been studied. Here, we investigated the variation among sibships of the acanthocephalan parasite, Pomphorhynchus laevis , in infecting and in immunodepressing its amphipod host, Gammarus pulex . We also assessed the covariation between infectivity, parasite-induced immune depression and host mortality (parasite virulence). We found that infecti…