ALBERT

All Library Books, journals and Electronic Records Telegrafenberg

X
feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
Filter
Collection
Keywords
Publisher
Years
  • 1
    Electronic Resource
    Electronic Resource
    SPECIES RICHNESS OF PARASITE ASSEMBLAGES: Evolution andPatterns (1997)
    Palo Alto, Calif. : Annual Reviews
    Annual Review of Ecology, Evolution, and Systematics 28 (1997), S. 341-358 
    Details
    ISSN: 0066-4162
    Source: Annual Reviews Electronic Back Volume Collection 1932-2001ff
    Topics: Biology
    Notes: Abstract Parasite communities are arranged into hierarchical levels of organization, covering various spatial and temporal scales. These range from all parasites within an individual host to all parasites exploiting a host species across its geographic range. This arrangement provides an opportunity for the study of patterns and structuring processes operating at different scales. Across the parasite faunas of various host species, several species-area relationships have been published, emphasizing the key role of factors such as host size or host geographical range in determining parasite species richness. When corrections are made for unequal sampling effort or phylogenetic influences, however, the strength of these relationships is greatly reduced, casting a doubt over their validity. Component parasite communities, or the parasites found in a host population, are subsets of the parasite fauna of the host species. They often form saturated communities, such that their richness is not always a reflection of that of the entire parasite fauna. The species richness of component communities is instead influenced by the local availability of parasite species and their probability of colonization. At the lowest level, infracommunities in individual hosts are subsets of the species occurring in the component community. Generally, their structure does not differ from that expected from a random assembly of available species, although comparisons with precise null models are still few. Overall studies of parasite communities suggest that the action of processes determining species richness of parasite assemblages becomes less detectable as focus shifts from parasite faunas to infracommunities.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1146/annurev.ecolsys.28.1.341
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 2
    Electronic Resource
    Electronic Resource
    Group-living and the richness of the parasite fauna in Canadian freshwater fishes (1991)
    Springer
    Oecologia 86 (1991), S. 390-394 
    Details
    ISSN: 1432-1939
    Keywords: Parasitism ; Freshwater fishes ; Group-living ; Ectoparasites ; Speices richness
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary An increased transmission of ectoparasites among individual animals is considered to be an inevitable cost of living in groups, since several kinds of ectoparasites require close proximity between large numbers of hosts for successful transmission. However, we do not know whether individuals belonging to group-living species incur a greater risk of ectoparasitism than individuals of solitary species. Here, using published data from 3 families (60 species) of Canadian freshwater fishes, I test the hypothesis that group-living species are host to more species of “contagious ectoparasites” (copepods and monogeneans) than solitary host species. As the different fish species have been studied with varying intensity, I used the mean number of parasite species recorded per study as a standard measure of parasite numbers. Multiple regression analyses were performed separately for each family to determine the effects of group-living and of 3 other variables (host size, age, and range) on the richness of the recorded parasite fauna. Once the effects of the other variables were removed, I found no significant effect of sociality on the richness of the parasite fauna per fish species, for contagious ectoparasites and other types of parasites. Neither of the other variables had any influence on the numbers of parasite species per fish species. These results suggest that a richer ectoparasite fauna is not a cost of group-living in fishes.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00317606
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 3
    Electronic Resource
    Electronic Resource
    Comparing the richness of metazoan ectoparasite communities of marine fishes: controlling for host phylogeny (1997)
    Springer
    Oecologia 110 (1997), S. 278-283 
    Details
    ISSN: 1432-1939
    Keywords: Key words Fish  ;  Parasites  ;  Phylogenetic contrasts  ;  Richness  ;  Water temperature
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Parasite communities are the product of acquisitions and losses of parasite species during the evolutionary history of their host. When comparing the parasite communities of different host species to assess the role of ecological variables as determinants of parasite species richness, a correction must be made for the possible phylogenetic inheritance of parasites from ancestral hosts independent of host ecology. We performed a comparative analysis of the metazoan ectoparasite communities on the heads and gills of 111 species of marine fish. The influences of host body size, host schooling behaviour and water temperature were tested after controlling for both sampling and phylogenetic effects. Overall, water temperature correlated positively with both parasite species richness and abundance, whereas fish size only correlated with parasite abundance. The correlation across all fish species between water temperature and parasite species richness was dependent on an outlier point. The results, however, generally held when fish from different biogeographical areas (Pacific and Atlantic) were analysed separately. In all analyses, parasite species richness always correlated strongly with parasite abundance. There was no evidence that schooling fish taxa harboured richer or more abundant ectoparasite communities than their non-schooling sister taxa, possibly because of the small number of contrasts available for that test. Overall, whereas both water temperature and host size affect the number of parasite individuals that can be harboured by a fish, only temperature appears important as a determinant of ectoparasite community richness.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s004420050160
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 4
    Electronic Resource
    Electronic Resource
    Population abundance and sex ratio in dioecious helminth parasites (1997)
    Springer
    Oecologia 111 (1997), S. 375-380 
    Details
    ISSN: 1432-1939
    Keywords: Key words Acanthocephalans ; Intensity of infection ; Nematodes ; Phylogenetic contrasts ; Prevalence
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Parasite populations are highly fragmented in space and time, and consist of aggregates of genetically similar individuals sharing the same host. To avoid inbreeding, theory predicts that female-biased sex ratios should be strongly favoured when either or both prevalence and intensity of infection are low. Other models indicate that if sex ratios are selected to increase the probability of mating, they should be less biased at a high intensity of infection in polygamous parasites, since at high intensities all females are mated. To test these predictions, the relationship between sex ratio and both the prevalence and intensity of infection was examined in comparative studies across 193 populations of nematode and acanthocephalan parasites. Sex ratios in these two dioecious, polygamous taxa are usually female biased. Among natural populations, no significant relationship was observed once the confounding effects of phylogeny had been removed. However, among experimental populations of nematodes, a negative relationship was found between intensity of infection and sex ratio, even after controlling for phylogeny. In other words, at high intensities, populations of nematodes are less female biased. This result must be treated with caution because of the unusually high numbers of worms per host in experimental infections. Nevertheless, combined with information on the proximate mechanisms regulating sex ratios in these parasites, it suggests a link between the characteristics of parasite populations and their sex ratio.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s004420050248
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 5
    Electronic Resource
    Electronic Resource
    Age-dependent effects of parasites on anti-predator responses in two New Zealand freshwater fish (1993)
    Springer
    Oecologia 96 (1993), S. 431-438 
    Details
    ISSN: 1432-1939
    Keywords: Parasitism ; Trematodes ; Anti-predator responses ; Age dependence ; New Zealand fish
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Parasites of all kinds affect the behaviour of their hosts, often making them more susceptible to predators. The associated loss in expected future reproductive success of infected hosts will vary among individuals, with younger ones having more lose than older ones. For this reason, young hosts would benefit more by opposing the effects of parasites than old ones. In a laboratory study, the effects of the trematode Telogaster opisthorchis on the anti-predator responses of the upland bully (Gobiomorphus breviceps) and of the common river galaxias (Galaxias vulgaris) were examined in relation to fish age. In a bully population where parasites were very abundant, the magnitude of the fish's anti-predator responses decreased as the number of parasites per fish increased, and this effect was significantly more pronounced in age 2 + and, to a lesser extent, age 3 + fish than in age 1 + fish. In another bully population where parasites were 10 times less abundant, similar effects were noticeable but not significant, whereas no effects of parasites on the responses of galaxiids to predators were apparent. Differences in the abundance of parasites and in their sites of infection in fish may explain the variability among host populations or species. However, in the bully population with high parasite abundance, parasitism has age-dependent effects on responses to predators, providing some support for the prediction that young fish with high expected future reproductive success invest more energy into opposing the effects of parasites than do older fish.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00317516
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 6
    Electronic Resource
    Electronic Resource
    A cleaner perspective on cleaning symbiosis (1993)
    Springer
    Reviews in fish biology and fisheries 3 (1993), S. 75-79 
    Details
    ISSN: 1573-5184
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00043298
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 7
    Electronic Resource
    Electronic Resource
    The effect of hypoxia on the vulnerability of guppies (Poecilia reticulata, Poeciliidae) to an aquatic predator (Astronotus ocellatus, Cichlidae) (1987)
    Springer
    Environmental biology of fishes 20 (1987), S. 285-292 
    Details
    ISSN: 1573-5133
    Keywords: Predator-prey relationships ; Predation risk ; Antipredator mechanism ; Respiration ; Aquatic surface respiration ; Cost of breathing ; Dissolved oxygen
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Synopsis When dissolved oxygen concentration was near saturation in a laboratory experiment, guppies that spent (a) more time at the surface and (b) more time moving had a higher probability of being captured by a predatory cichlid fish. With decreasing oxygen concentration surface time and percent time moving increased, but prey risk decreased. In addition, the qualitative correlates of risk changed; under hypoxic conditions, predation risk was lower for prey which spent more time at the surface and in motion. Thus, dissolved oxygen concentration influences both quantitative and qualitative aspects of risk from water-breathing predators.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00005299
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 8
    Electronic Resource
    Electronic Resource
    Have chondracanthid copepods co-speciated with their teleost hosts? (1999)
    Springer
    Systematic parasitology 44 (1999), S. 79-85 
    Details
    ISSN: 1573-5192
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract Chondracanthid copepods parasitise many teleost species and have a mobile larval stage. It has been suggested that copepod parasites, with free-living infective stages that infect hosts by attaching to their external surfaces, will have co-evolved with their hosts. We examined copepods from the genus Chondracanthus and their teleost hosts for evidence of a close co-evolutionary association by comparing host and parasite phylogenies using TreeMap analysis. In general, significant co-speciation was observed and instances of host switching were rare. The prevalence of intra-host speciation events was high relative to other such studies and may relate to the large geographical distances over which hosts are spread.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1006255822947
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 9
    Electronic Resource
    Electronic Resource
    Speciation and diversification of parasite lineages: an analysis of congeneric parasite species in vertebrates (1999)
    Springer
    Evolutionary ecology 13 (1999), S. 455-467 
    Details
    ISSN: 1573-8477
    Keywords: adaptive radiation ; comparative analysis ; gastrointestinal helminths ; host body mass ; latitude ; phylogeny ; species flocks
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The evolutionary diversification of living organisms is a central research theme in evolutionary ecology, and yet it remains difficult to infer the action of evolutionary processes from patterns in the distribution of rates of diversification among related taxa. Using data from helminth parasite communities in 76 species of birds and 114 species of mammals, the influence of four factors that may either be associated with or modulate rates of parasite speciation were examined in a comparative analysis. Two measures of the relative number of congeneric parasite species per host species were used as indices of parasite diversification, and related to host body mass, host density, latitude, and whether the host is aquatic or terrestrial. The occurrence of congeneric parasites was not distributed randomly with respect to these factors. Aquatic bird species tended to harbour more congeneric parasites than terrestrial birds. Large-bodied mammal species, or those living at low latitudes, harboured more congeneric parasites than small-bodied mammals, or than those from higher latitudes. Host density had no apparent association with either measures of parasite diversification. These patterns, however, reflect only the present-day distribution of parasite diversification among host taxa, and not the evolutionary processes responsible for diversification, because the apparent effects of the factors investigated disappeared once corrections were made for host phylogeny. This indicates that features other than host body size, host density, latitude, and whether the habitat is terrestrial or aquatic, have been the key driving forces in the diversification of parasitic helminth lineages.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1006703927711
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 10
    Electronic Resource
    Electronic Resource
    Density, body mass and parasite species richness of terrestrial mammals (1998)
    Springer
    Evolutionary ecology 12 (1998), S. 717-727 
    Details
    ISSN: 1573-8477
    Keywords: body mass ; density ; helminths ; independent contrasts ; mammals ; parasite richness
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract We investigated the relationships between helminth species richness and body mass and density of terrestrial mammals. Cross-species analysis and the phylogenetically independent contrast method produced different results. A non-phylogenetic approach (cross-species comparisons) led to the conclusion that parasite richness is linked to host body size. However, an analysis using phylogenetically independent contrasts showed no relationship between host body size and parasite richness. Conversely, a non-phylogenetic approach generated a negative relationship between parasite richness and host density, whereas the independent contrast method showed the opposite trend – that is, parasite richness is positively correlated with host density. From an evolutionary perspective, our results suggest that opportunities for parasite colonization depend more closely on how many hosts are available in a given area than on how large the hosts are. From an epidemiological point of view, our results confirm theoretical models which assume that host density is linked to the opportunity of a parasite to invade a population of hosts. Our findings also suggest that parasitism may be a cost associated with host density. Finally, we provide some support for the non-linear allometry between density and mammal body mass (Silva and Downing, 1995), and explain why host density and host body mass do not relate equally to parasite species richness.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1006537600093
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...