نتایج جستجو برای: parasitism
تعداد نتایج: 5401 فیلتر نتایج به سال:
Decline in landscape complexity owing to agricultural intensification may affect biodiversity, food web complexity and associated ecological processes such as biological control, but such relationships are poorly understood. Here, we analysed food webs of cereal aphids, their primary parasitoids and hyperparasitoids in 18 agricultural landscapes differing in structural complexity (42-93% arable...
BACKGROUND The metacommunity framework is crucial to the study of functional relations along environmental gradients. Changes in resource grain associated with increasing habitat fragmentation should generate uncoupled responses of interacting species with contrasted dispersal abilities. METHODOLOGY/PRINCIPAL FINDINGS Here we tested whether the intensity of parasitism was modified by increasi...
By sequentially and histologically studying the evolution of a virulent Y strain infection in young mice, two striking features were observed: a) the progressive increase of macrophage parasitism in the spleen followed by a massive destruction of both macrophages and parasites at the height of infection, which coincided with a sudden drop in parasitemia and which often preceded animal death; b)...
The mark-recapture method allows analysis on the variation in the abundance of bat ectoparasites at consecutive captures. The objectives of this study were to compare the pattern of Streblidae parasitism between capture and recapture of C. perspicillata; ascertain whether the abundance of Streblidae varied with time after removal of ectoparasites at capture and analyze whether the intensity of ...
Despite extraordinary diversity of free-living species, a comparatively small fraction of nematodes are parasites of plants. These parasites represent at least three disparate clades in the nematode tree of life, as inferred from rRNA sequences. Plant parasites share functional similarities regarding feeding, but many similarities in feeding structures result from convergent evolution and have ...
Parasitism genes expressed in the esophageal gland cells of root-knot nematodes encode proteins that are secreted into host root cells to transform the recipient cells into enlarged multinucleate feeding cells called giant-cells. Expression of a root-knot nematode parasitism gene which encodes a novel 13-amino-acid secretory peptide in plant tissues stimulated root growth. Two SCARECROW-like tr...
How global warming will affect insect parasitoids and their role as natural enemies of insect pests is difficult to assess within a short period of time. Considering that elevation gradients can be used as analogues for global warming, we carried out meta-analyses of 27 correlations between parasitoid richness and elevation and 140 correlations between parasitism rate and elevation in natural a...
The epigenetic landscape illustrates how cells differentiate through the control of gene regulatory networks. Numerous studies have investigated epigenetic gene regulation but there are limited studies on how the epigenetic landscape and the presence of pathogens influence the evolution of host traits. Here, we formulate a multistable decision-switch model involving several phenotypes with the ...
The foraging behaviour of a parasitoid insect species includes the host's habitat and subsequent location of the host. Habitats substrate, substrate moisture, and light levels can affect the host searching of different species of parasitoids. However, the depth at which parasitoids concentrate their search effort is another important ecological characteristic and plays an important role in loca...
Phylogenetic studies on insect social parasites have found very close host-parasite relationships, and these have often been interpreted as providing evidence for sympatric speciation. However, such phylogenetic inferences are problematic because events occurring after the origin of parasitism, such as extinction, host switching and subsequent speciation, or an incomplete sampling of taxa, coul...
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