Search results for "SITE"
showing 10 items of 8388 documents
Intestinal distribution and fecundity of two species ofDiplostomumparasites in definitive hosts
2005
This paper investigated the intestinal distribution and fecundity of 2 species ofDiplostomumparasites,D. spathaceumandD. pseudospathaceum, in 2 species of definitive hosts, herring gull (Larus argentatus) and common gull (L. canus), using both empirical field data and experimental infections. At the level of individual hosts, the parasite species occupied different parts within the intestine, but the fecundity of the worms, measured as the number of eggs in the uterus, did not differ between the parasite species except in wild common gulls. Interestingly, egg numbers in individual hosts were positively correlated between the parasite species suggesting that some birds provided better resour…
Intraguild interactions between two egg parasitoids of a true bug in semi-field and field conditions.
2014
International audience; Research on interspecific competitive interactions among insect parasitoids has often been characterized by laboratory studies in which host insects are exposed to female parasitoids of different species in various sequences and combinations. In the last years, an increasing number of studies have investigated interspecific interactions under field and semi-field conditions although just a few number of works focused on egg parasitoids. In this work, we undertook a two-year study to investigate interspecific interactions between Trissolcus basalis (Wollaston) (Hymenoptera: Platygastridae) and Ooencyrtus telenomicida (Vassiliev) (Hymenoptera: Encyrtidae), two egg para…
Do highly ornamented and less parasitized males have high quality sperm? - an experimental test for parasite-induced reproductive trade-offs in Europ…
2014
Parasites take their resources from hosts and thus directly reduce available resources for hosts’ own body functions, such as growth and reproduction. Furthermore, parasite infections cause significant indirect costs to their hosts in terms of increased investments on immune defense. In this study, we investigated the impact of parasite infection on the sperm quality and expression of secondary sexual ornamentation (saturation of the red abdominal colouration and number of breeding tubercles) in the Eurasian minnow (Phoxinus phoxinus). We exposed minnows to a high and low dose of common nonspecific fish ectoparasite, the glochidia larvae of duck mussel (Anodonta anatina) and tested whether …
Quelles stratégies pour les musées sur internet ? Entre " click and mortar " et " mortar and click "
2011
Many companies now use the Internet as part of a click & mortar strategy. This strategy is also used in the museum field, but its consequences have not been evaluated yet. A quantitative study carried out on a sample of 388 visitors, at the Bibracte Museum (France), indicates that the quality of an internet website, as well as the satisfaction and trust experienced by Internet users when browsing, have direct positive influence on word-of mouth and the actual museum visit. It seems therefore appropriate to integrate the internet website to the whole management of cultural and artistic activities, without forgetting to take into account the specificities of this particular field.
Data from: Gene expression patterns underlying parasite-induced alterations in host behaviour and life history
2015
Many parasites manipulate their hosts’ phenotype. In particular, parasites with complex life cycles take control of their intermediate hosts’ behaviour and life history to increase transmission to their definitive host. The proximate mechanisms underlying these parasite-induced alterations are poorly understood. The cestode Anomotaenia brevis affects the behaviour, life history and morphology of parasitized Temnothorax nylanderi ants and indirectly of their unparasitized nestmates. To gain insights on how parasites alter host phenotypes, we contrast brain gene expression patterns of T. nylanderi workers parasitized with the cestode, their unparasitized nestmates and unparasitized workers fr…
Data from: Virus epidemics can lead to a population-wide spread of intragenomic parasites in a previously parasite-free asexual population
2014
In a recent issue of Molecular Ecology the role of intragenomic parasites in maintaining sexual reproduction was both experimentally evaluated by Kraaijeveld et al. and discussed by Crespi and Schwander. The prevalence of sex is difficult to explain, due to its costs when compared with asexual reproduction. Yet, as reviewed by Crespi and Schwander, sex can be favorable in the presence of proliferating transposons. Transposons are similar to mutations, in that their integration to non-neutral loci is likely to have deleterious effects, and sexual recombination provides a potential mechanism to confine their accumulation.
Data from: 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 uninfecte…
Data from: Sympatric diversification vs. immigration: deciphering host-plant specialization in a polyphagous insect, the stolbur phytoplasma vector H…
2013
The epidemiology of vector transmitted plant diseases is highly influenced by dispersal and the host-plant range of the vector. Widening the vector's host range may increase transmission potential, whereas specialization may induce specific disease cycles. The process leading to a vector's host shift and its epidemiological outcome is therefore embedded in the frameworks of sympatric evolution vs. immigration of preadapted populations. In this study, we analyse whether a host shift of the stolbur phytoplasma vector, Hyalesthes obsoletus from field bindweed to stinging nettle in its northern distribution range evolved sympatrically or by immigration. The exploitation of stinging nettle has l…
Data from: Reciprocal interaction matrix reveals complex genetic and dose-dependent specificity among coinfecting parasites
2012
Understanding genetic specificity in factors determining the outcome of host-parasite interactions is especially important as it contributes to parasite epidemiology, virulence, and maintenance of genetic variation. Such specificity, however, is still generally poorly understood. We examined genetic specificity in interactions among coinfecting parasites. In natural populations, individual hosts are often simultaneously infected by multiple parasite species and genotypes that interact. Such interactions could maintain genetic variation in parasite populations if they are genetically specific so that the relative fitness of parasite genotypes varies across host individuals depending on (1) t…
Data from: The joint evolution of the Myxozoa and their alternate hosts: a cnidarian recipe for success and vast biodiversity
2018
The relationships between parasites and their hosts are intimate, dynamic and complex; the evolution of one is inevitably linked to the other. Despite multiple origins of parasitism in the Cnidaria, only parasites belonging to the Myxozoa are characterized by a complex life cycle, alternating between fish and invertebrate hosts, as well as by exceptionally high species diversity. This inspired us to examine the history of reciprocal interactions and adaptive radiations in myxozoans and their hosts by determining the degree of congruence between their phylogenies and by timing the emergence of myxozoan lineages in relation to their hosts. Recent genomic analyses suggested a common origin of …