Search results for "isäntälajit"

Divergent parasite infections in sympatric cichlid species in Lake Victoria

2018

Parasitism has been proposed as a factor in host speciation, as an agent affecting coexistence of host species in species-rich communities and as a driver of post-speciation diversification. Young adaptive radiations of closely related host species of varying ecological and genomic differentiation provide interesting opportunities to explore interactions between patterns of parasitism, divergence and coexistence of sympatric host species. Here, we explored patterns in ectoparasitism in a community of 16 fully sympatric cichlid species at Makobe Island in Lake Victoria, a model system of vertebrate adaptive radiation. We asked whether host niche, host abundance or host genetic differentiatio…

Infection, specificity and host manipulation of Australapatemon sp. (Trematoda, Strigeidae) in two sympatric species of leeches (Hirudinea)

2017

SUMMARYFactors that drive parasite specificity and differences in infection dynamics among alternative host species are important for ecology and evolution of host–parasite interactions, but still often poorly known in natural systems. Here, we investigated spatiotemporal dynamics of infection, host susceptibility and parasite-induced changes in host phenotype in a rarely explored host–parasite system, theAustralapatemonsp. trematode infecting two sympatric species of freshwater leeches,Erpobdella octoculataandHelobdella stagnalis. We show significant variation in infection abundance between the host species in both space and time. Using experimental infections, we also show that most of th…

The roles of foraging environment, host species, and host diet for a generalist pupal parasitoid

2018

Morphological traits predict host-tree specialization in wood-inhabiting fungal communities

2020

Tree species is one of the most important determinants of wood-inhabiting fungal community composition, yet its relationship with fungal reproductive and dispersal traits remains poorly understood. We studied fungal communities (total of 657 species) inhabiting broadleaved and coniferous dead wood (total of 192 logs) in 12 semi-natural boreal forests. We utilized a trait-based hierarchical joint species distribution model to examine how the relationship between dead wood quality and species occurrence correlates with reproductive and dispersal morphological traits. Broadleaved trees had higher species richness than conifers, due to discomycetoids and pyrenomycetoids specializing in them. Re…

Parasite transmission in aquatic ecosystems under temperature change: effects of host activity and elimination of parasite larvae by filter‐feeders

2020

A moderate raise in temperature was suggested to enhance the impact of parasites on aquatic ecosystems. Under higher temperatures, poikilothermic animals (e.g. fish) increase their activity, which can result in a more frequent encounter with parasites. However, temperature increase may also trigger processes counteracting an increased risk of parasitic infections. Thus, the removal of free‐living stages of parasites by filter‐feeding organisms can increase with temperature and potentially mitigate disease risk in ecosystems under climate change. We aimed to study whether an increased infection transmission under higher temperatures can be compensated by the increased removal of parasitic la…

Risk factors for Lyme disease : A scale-dependent effect of host species diversity and a consistent negative effect of host phylogenetic diversity

2021

Biodiversity can influence disease risk. One example of a diversity-disease relationship is the dilution effect, which suggests higher host species diversity (often indexed by species richness) reduces disease risk. While numerous studies support the dilution effect, its generality remains controversial. Most studies of diversity-disease relationships have overlooked the potential importance of phylogenetic diversity. Furthermore, most studies have tested diversity-disease relationships at one spatial scale, even though such relationships are likely scale dependent. Using Lyme disease as a model system, we investigated the effects of host species richness and phylogenetic relatedness on the…

Spatiotemporal and gender-specific parasitism in two species of gobiid fish

2018

Parasitism is considered a major selective force in natural host populations. Infections can decrease host condition and vigour, and potentially influence, for example, host population dynamics and behavior such as mate choice. We studied parasite infections of two common marine fish species, the sand goby (Pomatoschistus minutus) and the common goby (Pomatoschistus microps), in the brackish water Northern Baltic Sea. We were particularly interested in the occurrence of parasite taxa located in central sensory organs, such as eyes, potentially affecting fish behavior and mate choice. We found that both fish species harbored parasite communities dominated by taxa transmitted to fish through …

Täpläravun (Pacifastacus leniusculus) vaikutus ahventen (Perca fluviatilis) loisyhteisöihin Päijänteellä

2010

Täplärapu (Pacifastacus leniusculus) on tulokaslaji Suomen vesistöissä. Sen on käyttäytymisellään ja ravinnonkäytöllään todettu vähentävän elinalueidensa eliöyhteisöjen monimuotoisuutta. Esimerkiksi Päijänteellä on havaittu joidenkin pohjaeläinten kuten kotiloiden tiheyksien olevan alhaisempia ravun elinalueilla kuin ravuttomilla alueilla. Pohjaselkärangattomat ovat välttämättömiä väli-isäntiä monelle kalan loiselle. Tässä tutkimuksessa selvitettiin, millaisia muutoksia täplärapu voi välillisesti aiheuttaa kalojen loisyhteisöissä muuttamalla pohjaeläinten runsautta. Päijänteeltä valittiin viisi toisistaan riippumatonta ravullista ja ravutonta aluetta. Jokaiselta alueelta pyydettiin mahdolli…

The effects of Borrelia infection on its wintering rodent host

2022

AbstractIn seasonal environments, appropriate adaptations are crucial for organisms to maximize their fitness. For instance, in many species, the immune function has been noticed to decrease during winter, which is assumed to be an adaptation to the season’s limited food availability. Consequences of an infection on the health and survival of the host organism could thus be more severe in winter than in summer. Here, we experimentally investigated the effect of a zoonotic, endemic pathogen, Borrelia afzelii infection on the survival and body condition in its host, the bank vole (Myodes glareolus), during late autumn–early winter under semi-natural field conditions in 11 large outdoor enclos…

Coinfection patterns of two marine apicomplexans are not associated with genetic diversity of their polychaete host.

2022

Coinfections of two or more parasites within one host are more of a rule than an exception in nature. Interactions between coinfecting parasites can greatly affect their abundance and prevalence. Characteristics of the host, such as genetic diversity, can also affect the infection dynamics of coinfecting parasites. Here we investigate for the first time the association of coinfection patterns of two marine apicomplexans, Rhytidocystis sp. and Selenidium pygospionis, with the genetic diversity of their host, the polychaete Pygospio elegans, from natural populations. Host genetic diversity was determined with seven microsatellite loci and summarized as allelic richness, inbreeding coefficient…