Search results for "HOST-PARASITE"
showing 10 items of 355 documents
Manipulative parasites may not alter intermediate host distribution but still enhance their transmission: field evidence for increased vulnerability …
2013
SUMMARYBehavioural alterations induced by parasites in their intermediate hosts can spatially structure host populations, possibly resulting in enhanced trophic transmission to definitive hosts. However, such alterations may also increase intermediate host vulnerability to non-host predators. Parasite-induced behavioural alterations may thus vary between parasite species and depend on each parasite definitive host species. We studied the influence of infection with 2 acanthocephalan parasites (Echinorhynchus truttae and Polymorphus minutus) on the distribution of the amphipod Gammarus pulex in the field. Predator presence or absence and predator species, whether suitable definitive host or …
Carotenoid-based colour of acanthocephalan cystacanths plays no role in host manipulation.
2009
Manipulation by parasites is a catchy concept that has been applied to a large range of phenotypic alterations brought about by parasites in their hosts. It has, for instance, been suggested that the carotenoid-based colour of acanthocephalan cystacanths is adaptive through increasing the conspicuousness of infected intermediate hosts and, hence, their vulnerability to appropriate final hosts such as fish predators. We revisited the evidence in favour of adaptive coloration of acanthocephalan parasites in relation to increased trophic transmission using the crustacean amphipodGammarus pulexand two species of acanthocephalans,Pomphorhynchus laevisandPolymorphus minutus. Both species show car…
Parasite-induced alteration of plastic response to predation threat: increased refuge use but lower food intake in Gammarus pulex infected with the a…
2014
6 pages; International audience; Larvae of many trophically-transmitted parasites alter the behaviour of their intermediate host in ways that increase their probability of transmission to the next host in their life cycle. Before reaching a stage that is infective to the next host, parasite larvae may develop through several larval stages in the intermediate host that are not infective to the definitive host. Early predation at these stages results in parasite death, and it has recently been shown that non-infective larvae of some helminths decrease such risk by enhancing the anti-predator defences of the host, including decreased activity and increased sheltering. However, these behavioura…
Multidimensionality in host manipulation mimicked by serotonin injection.
2014
Manipulative parasites often alter the phenotype of their hosts along multiple dimensions. ‘Multidimensionality’ in host manipulation could consist in the simultaneous alteration of several physiological pathways independently of one another, or proceed from the disruption of some key physiological parameter, followed by a cascade of effects. We compared multidimensionality in ‘host manipulation’ between two closely related amphipods, Gammarus fossarum and Gammarus pulex, naturally and experimentally infected with Pomphorhynchus laevis (Acanthocephala), respectively. To that end, we calculated in each host–parasite association the effect size of the difference between infected and uninfect…
Larval size in acanthocephalan parasites : Influence of intraspecific competition and effects on intermediate host behavioural changes
2012
Abstract Background Parasites often face a trade-off between exploitation of host resources and transmission probabilities to the next host. In helminths, larval growth, a major component of adult parasite fitness, is linked to exploitation of intermediate host resources and is influenced by the presence of co-infecting conspecifics. In manipulative parasites, larval growth strategy could also interact with their ability to alter intermediate host phenotype and influence parasite transmission. Methods We used experimental infections of Gammarus pulex by Pomphorhynchus laevis (Acanthocephala), to investigate larval size effects on host behavioural manipulation among different parasite sibshi…
Persistent establishment of a tropical disease in Europe: the preadaptation of schistosomes to overwinter
2019
International audience; Background: Global changes promote the spread of infectious diseases worldwide. In this context, tropical uro-genital schistosomiasis is now permanently established in Corsica since its first emergence in 2013. The local persistence of the tropical pathogens (schistosomes) responsible for urogenital schistosomiasis at such latitudes might be explained by (i) the presence of its intermediate host, the snail Bulinus truncatus, (ii) the recurrent local reseeding of schistosomes by their vertebrate hosts (either human or animal) every summer, and/or (iii) the maintenance and survival of schistosomes within their snail hosts over winter.Methods: In this study we conducted…
Multidimensionality and intra-individual variation in host manipulation by an acanthocephalan
2008
Parasitology, 135 (5)
Long-lasting effect of stress on susceptibility of a freshwater clam to copepod parasitism.
2005
The question whether a stress event can have a long-lasting effect on susceptibility to parasites was studied using a freshwater bivalve clam and its crustacean parasite as a model system. Anodonta piscinalis clams were collected from 2 populations during August–September 2002. Clams were transported to the laboratory and marked. The stressed clams were subjected to low oxygen for 25 days, while the unstressed control clams were caged in their lakes of origin for the same period. Then the clams were transported to a third lake where they were exposed to natural infections by the ergasilid copepod, Paraergasilus rylovi , 11 months after the stress event. The stressed clams were more intensiv…
Influence of trematode parasitism on the growth of a bivalve host in the field.
1998
Abstract Trematode-induced gigantism of molluscs, enhanced growth of trematode-parasitised individuals, has been observed in many laboratory studies. This study reports the effect of the sterilising trematode, Rhipidicotyle fennica , on the growth of the freshwater clam Anodonta piscinalis under field conditions. In addition to single infections (prevalence 44%), a few clams (3%) were infected with both R. fennica and Rhipidocotyle campanula . Parasite-induced gigantism was not found; parasites lowered host growth. The decrease in growth was correlated with the quantity of parasite material. Clams with double infections grew the least, although they did not differ significantly from hosts w…
Optimum and Maximum Host Sizes at Parasitism for the Endoparasitoid <I>Hyposoter didymator</I> (Hymenoptera: Ichneumonidae) Differ Greatl…
2007
Host size is considered a reliable indicator of host quality and an important determinant of parasitoid fitness. Koinobiont parasitoids attack hosts that continue feeding and growing during parasitism. In contrast with hemolymph-feeding koinobionts, tissue-feeding koinobionts face not only a minimum host size for successful development but also a maximum host size, because consumption of the entire host is often necessary for successful egression. Here we study interactions between a generalist tissue-feeding larval endoparasitoid, Hyposoter didymator Thunberg (Hymenoptera: Ichneumonidae) and two of its natural hosts, Spodoptera exigua Hübner and Chrysodeixis chalcites Esper (Lepidoptera: N…