نتایج جستجو برای: host species population

تعداد نتایج: 1361902  

Journal: :The American naturalist 2001
I Hanski M C Singer

Species living in highly fragmented landscapes often occur as metapopulations with frequent population turnover. Turnover rate is known to depend on ecological factors, such as population size and connectivity, but it may also be influenced by the phenotypic and genotypic composition of populations. The Glanville fritillary butterfly (Melitaea cinxia) in Finland uses two host-plant species that...

2018
Pavla Bartošová-Sojková Alena Lövy Cecile C Reed Martina Lisnerová Tereza Tomková Astrid S Holzer Ivan Fiala

INTRODUCTION Intertidal rock pools where fish and invertebrates are in constant close contact due to limited space and water level fluctuations represent ideal conditions to promote life cycles in parasites using these two alternate hosts and to study speciation processes that could contribute to understanding the roles of parasitic species in such ecosystems. MATERIAL AND METHODS Gall bladde...

Journal: :The American naturalist 2006
John J Dennehy Nicholas A Friedenberg Robert D Holt Paul E Turner

Viruses can occasionally emerge by infecting new host species. However, the early phases of emergence can hinge upon ecological sustainability of the virus population, which is a product of both within-host population growth and between-host transmission. Insufficient growth or transmission can force virus extinction before the latter phases of emergence, where genetic adaptations that improve ...

Journal: :Proceedings. Biological sciences 2016
Abhilash Nair Toby Fountain Suvi Ikonen Sami P Ojanen Saskya van Nouhuys

A fragmented habitat becomes increasingly fragmented for species at higher trophic levels, such as parasitoids. To persist, these species are expected to possess life-history traits, such as high dispersal, that facilitate their ability to use resources that become scarce in fragmented landscapes. If a specialized parasitoid disperses widely to take advantage of a sparse host, then the parasito...

Journal: :The American naturalist 2000
Dieter Ebert Marc Lipsitch Katrina L Mangin

Parasites have been shown to reduce host density and to induce host population extinction in some cases but not in others. Epidemiological models suggest that variable effects of parasites on individual hosts can explain this variability on the population level. Here, we aim to support this hypothesis with a specific epidemiological model using a cross-parasite species approach. We compared the...

2014
Diana Kim John Waller Andrea S. Aspbury Caitlin R. Gabor

Gynogenetic species rely on sperm from heterospecifics for reproduction but do not receive genetic benefits from mating because none of the paternal genome is incorporated into offspring. The gynogenetic Amazon molly (Poecilia formosa) is a species of hybrid origins that are sympatric with one of the two parent species that provide sperm for reproduction, P. latipinna or P. mexicana. Amazons sh...

2005
P. R. Holmstad P. J. Hudson A. Skorping

Despite the fact that most host populations are infected by a community of different parasite species, the majority of empirical studies have focused on the interaction between the host and a single parasite species. Here, we explore the hypothesis that host population dynamics are affected both by single parasite species and by the whole parasite community. We monitored population density and ...

2013
Corlett W Wood Hannah M Donald Vincent A Formica Edmund D Brodie

In heterogeneous environments, landscape features directly affect the structure of genetic variation among populations by functioning as barriers to gene flow. Resource-associated population genetic structure, in which populations that use different resources (e.g., host plants) are genetically distinct, is a well-studied example of how environmental heterogeneity structures populations. Howeve...

2016
David Baker Sinead Barrett Colin M Beale Terry J Crawford Sam Ellis Tallulah Gullett Peter J Mayhew Mark S Parsons Penny Relf Paul Robertson Julian Small Dave Wainwright

The conditions required by rare species are often only approximately known. Monitoring such species over time can help refine management of their protected areas. We report population trends of a rare moth, the Dark Bordered Beauty Epione vespertaria (Linnaeus, 1767) (Lepidoptera: Geometridae) at its last known English site on a protected lowland heath, and those of its host-plant, Salix repens...

Journal: :Conservation biology : the journal of the Society for Conservation Biology 2014
Annemarieke Spitzen-Van Der Sluijs An Martel Caspar A Hallmann Wilbert Bosman Trenton W J Garner Pascale Van Rooij Robert Jooris Freddy Haesebrouck Frank Pasmans

The inconsistent distribution of large-scale infection mediated die-offs and the subsequent population declines of several animal species, urges us to understand how, when, and why species are affected by disease. It is often unclear when or under what conditions a pathogen constitutes a threat to a host. Often, variation of environmental conditions plays a role. Globally Batrachochytrium dendr...

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