نتایج جستجو برای: parasitism

تعداد نتایج: 5401  

Journal: :Proceedings. Biological sciences 2011
Vesna Gagic Teja Tscharntke Carsten F Dormann Bernd Gruber Anne Wilstermann Carsten Thies

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...

2010
Benjamin Bergerot Romain Julliard Michel Baguette

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...

1998
Zulmira M.S. Cordeiro Ana Cristina Gonzalez Dahia Zilton A. Andrade

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)...

Journal: :Revista brasileira de parasitologia veterinaria = Brazilian journal of veterinary parasitology : Orgao Oficial do Colegio Brasileiro de Parasitologia Veterinaria 2011
Elizabete Captivo Lourenço Carlos Eduardo Lustosa Esbérard

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 ...

Journal: :Annual review of phytopathology 2004
J G Baldwin S A Nadler B J Adams

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 ...

Journal: :Molecular plant-microbe interactions : MPMI 2006
Guozhong Huang Ruihua Dong Rex Allen Eric L Davis Thomas J Baum Richard S Hussey

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...

Journal: :Biology letters 2013
Christelle Péré Hervé Jactel Marc Kenis

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...

Journal: :Infection, genetics and evolution : journal of molecular epidemiology and evolutionary genetics in infectious diseases 2017
Mark Jayson V Cortez Jomar F Rabajante Jerrold M Tubay Ariel L Babierra

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 ...

2014
Christine Frederickx Jessica Dekeirsschieter François J. Verheggen Eric Haubruge

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...

Journal: :Molecular phylogenetics and evolution 2007
Jaclyn A Smith Simon M Tierney Yung Chul Park Susan Fuller Michael P Schwarz

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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