Search results for "generalist"
showing 10 items of 92 documents
Host–virus evolutionary dynamics with specialist and generalist infection strategies: Bifurcations, bistability, and chaos
2019
In this work, we have investigated the evolutionary dynamics of a generalist pathogen, e.g., a virus population, that evolves toward specialization in an environment with multiple host types. We have particularly explored under which conditions generalist viral strains may rise in frequency and coexist with specialist strains or even dominate the population. By means of a nonlinear mathematical model and bifurcation analysis, we have determined the theoretical conditions for stability of nine identified equilibria and provided biological interpretation in terms of the infection rates for the viral specialist and generalist strains. By means of a stability diagram, we identified stable fixed…
Environmental distribution of prokaryotic taxa
2010
14 pages, 5 figures, 1 table, 10 additional files avalaible [http://www.biomedcentral.com/content/supplementary/1471-2180-10- 85-S10.PDF ]
Niche segregation of coexisting Arctic charr (Salvelinus alpinus) and brown trout (Salmo trutta) constrains food web coupling in subarctic lakes
2012
SUMMARY 1. Generalist fish species are recognised as important couplers of benthic and pelagic food-web compartments in lakes. However, interspecific niche segregation and individual specialisation may limit the potential for generalistic feeding behaviour. 2. We studied summer habitat use, stomach contents and stable isotopic compositions of the generalist feeder Arctic charr coexisting with its common resource competitor brown trout in five subarctic lakes in northern Norway to reveal population-level and individual-level niche plasticity. 3. Charr and trout showed partial niche segregation in all five lakes. Charr used all habitat types and a wide variety of invertebrate prey including z…
Factors affecting the distribution of recent lacustrine ostracoda from the Caicedo de Yuso-Arreo Lake (Western Ebro Basin, Spain)
2005
Recent Ostracoda assemblages of the Caicedo de Yuso Lake have been described as representative of palustrine/lacustrine environments in Iberian temperate lakes. This study considers the changes in assemblages at a fixed station during two consecutive annual cycles, as well as their distribution in summer and winter profiles of the lake. Total sample-assemblages have been quantified as species diversities, measured by the Shannon-Wiener index H (S). The trends of this index are compared to physical parameters (temperature, conductivity, dissolved oxygen, CO2) of the bottom waters of this lake. The Ostracoda assemblages (8100 adults and juvenile living specimens, belonging to 20 species) are …
Energy density and its variation in space limit species richness of boreal forest birds
2012
Aim An area’s ability to support species may be dependent not only on the total amount of available energy it contains but also on energy density (i.e. available energy per unit area). Acknowledging these two aspects of energy availability may increase mechanistic understanding of how increased energy availability results in increased species richness. We studied the relationship between energy density, its variation in space and boreal forest bird species richness and investigated two possible mechanisms: (1) metabolic constraints of organisms, and (2) increased resource availability for specialists. Location Protected areas in Finland’s boreal forest. Methods We tested whether bird spe…
Effects of Local Disturbance of Tropical Forests on Frugivores and Seed Removal of a Small-Seeded Afrotropical Tree
2008
Small-scale, local disturbance of tropical forests, for example from selective logging, is widespread, but its effects on biodiversity and ecosystem function have rarely been studied. In 3 East African tropical rainforests, we investigated the effect of different levels of local forest disturbance on the frugivore community and on tree visitation and fruit removal rates of the small-seeded tree Celtis durandii. We quantified birds and primates in little and heavily disturbed sites, distinguishing between forest specialists, forest generalists, and forest visitors. We quantified frugivorous tree visitors and seed removal rates of C. durandii trees in the same sites. Forest disturbance reduce…
Intraspecific Variation of Host Plant and Locality Influence the Lepidopteran-Parasitoid System of <I>Brassica oleracea</I> Crops
2013
ABSTRACT The aim of the study was to investigate the attractiveness to herbivores and parasitoids of two cultivars of Brassica oleracea L., namely, B. oleracea variety acephala (kale) and B. oleracea variety capitata (cabbage), that exhibit differences of morphological and biochemical traits. To this end, field samplings were replicated at seven localities in Galicia (northwestern Spain). Three specialist and three generalist lepidopteran species were sampled. In total, 7,050 parasitoids were obtained, belonging to 18 genera and 22 species. The results showed that 1) parasitism rate and parasitoid species richness changed with locality and was higher in cabbage, although this crop had lower…
“Generalist” Journals between Dissemination of Economics and Regime Propaganda
2019
Early in the 20th, generalist journals – a kind of press which had its major diffusion in the nineteenth century – continue to accommodate the contributions of economists offering a specific debating space. However, with the affirmation of fascist ideology, generalist periodicals progressively ceased to exist or to host economists’ articles. Thus, the main object of this research consists in clarifying what could be intended by “generalism” and in relation to which events and ideological pressures it disappeared as a different way to do journalism in a dialectic interplay with specialization. The paper reviews the panorama of generalist journals focusing on the impact of the Fascist regime …
Effects of forest regeneration on the structure of bird communities in northern Finland
1985
Breeding bird communities in five stages of secondary forest succession were studied in northeastern Finland in 1980–82. Three groups of communities were distinguished: open land, brush phase and forest communities, dominated by Motacilla alba and Oenanthe oenanthe, Phylloscopus trochilus and Anthus trivialis, Phylloscopus trochilus and Fringilla montifringilla, respectively. Pair density, number of species, biomass of adult birds and species diversity increased in the course of succession, none of these, however, monotonously. Average bird weight showed a decreasing trend although the variation was considerable. The degree of specialization in communities (measured by ratios derived from n…
Arabidopsis thalianagenes contributing to differences in the outcome of infection with generalist and specialist strains ofTurnip mosaic virusidentif…
2020
AbstractPathogens can be classified as generalists or specialists depending on their host breadth. While generalists are able to successfully infect a wide variety of host species, the host range of specialists is limited to a few related species. Even though generalists seem to gain an advantage due to their wide host range, they usually pay a cost in terms of fitness within each host species (i.e., the jack-of-all trades, master of none). On the contrary, specialists have high fitness within their own host. A highly relevant yet poorly explored question is whether generalist and specialist viruses differ in the way they interact with their host’s gene expression networks. To identify host…