Relative infection levels and taxonomic distances among the host species used by a parasite: insights into parasite specialization

Parasitology ◽  
2004 ◽  
Vol 130 (1) ◽  
pp. 109-115 ◽  
Author(s):  
R. POULIN

Parasites often exploit more than one host species at any stage in their life-cycle, but the extent to which these host species are used varies greatly. Parasites typically achieve their highest prevalence, intensity and/or abundance in one host species (the principal host), whereas infection levels in auxiliary hosts range from relatively high to very low. The present study examines what influences the distribution of parasite individuals among their different host species, using metazoan parasites that use freshwater fish as their definitive or only host. Specifically, I test the hypothesis that differences in relative infection levels by a parasite among its auxiliary hosts are proportional to the taxonomic distance between the respective auxiliary hosts and the parasite's principal host. Taxonomic distance among hosts is a surrogate measure of their similarity in terms of ecology, physiology and immunology. Using data on 29 parasite species and 6 fish communities, for a total of 47 parasite-locality combinations, it was found that taxonomic distance between the auxiliary hosts and the principal host had no real influence on infection levels in auxiliary hosts, measured as either prevalence, intensity or abundance. The analysis revealed differences in the degree of specialization among major groups of parasites: in terms of abundance or intensity, auxiliary hosts were less important for cestodes than for nematodes and copepods. The lack of an effect of taxonomic distance may indicate that ecological similarity among host species, arising from convergence and not from relatedness, is more important than host phylogeny or taxonomy. Although the results are based on a limited number of parasite taxa, they suggest that parasites may be opportunistic in their colonization of new hosts, and not severely constrained by evolutionary baggage.

Zootaxa ◽  
2003 ◽  
Vol 394 (1) ◽  
pp. 1 ◽  
Author(s):  
AHMET ÖKTENER

A checklist of the metazoon parasites of freshwater fish in Turkey has been compiled from parasitological studies done in Turkey between 1964 and 2003. The parasite species list is arranged by phylum and class, providing parasite species name and author, host fish, location of host fish capture and author and date of published record. The host list consists of all parasite species listed by host species. One hundred and thirteen parasite species are listed from 41 host species belonging to 26 genera.


2015 ◽  
Vol 16 (1) ◽  
pp. 1-56 ◽  
Author(s):  
Ahmet Öktener

AbstractThis new checklist is an update of helminths of freshwater fish from Turkey. The last publication of a checklist of helminth parasites of freshwater fish in Turkey was over 11 years ago (Öktener, 2003), and there have been a number of new records. This update includes additional records and allows for the correction of errors and omissions that were present in the preceding version. The revision literature indicated the occurrence of 123 parasite species which included 60 monogeneans, 20 digeneans, 20 cestodes, 11 nematodes, seven acanthocephalans, five annelids from 71 different wild fish (64 native, four transitional, three introduced fish) species from freshwater in Turkey. Parasites not identified to species level are listed separately, and not included in the resulting comments, because of reporting different host species. Cyprinidae, with 50 species, is the dominant family among the examined fish with regard to species diversity


Parasitology ◽  
2005 ◽  
Vol 130 (6) ◽  
pp. 709-715 ◽  
Author(s):  
R. POULIN ◽  
D. MOUILLOT

Different animal species have different probabilities of being discovered and described by scientists, and these probabilities are determined to a large extent by the biological characteristics of these species. For instance, species with broader geographical ranges are more likely to be encountered by collectors than species with restricted distributions; indeed, the size of the geographical range is often the best predictor of a species' date of description. For parasitic organisms, host specificity may be similarly linked to the probability of a species being found. Here, using data on 170 helminth species parasitic in freshwater fishes, we show that host specificity is associated with the year in which the helminths were described. Helminths that exploit more host species, and to a lesser degree those that exploit a broader taxonomic range of host species, tend to be discovered earlier than the more host-specific helminths. This pattern was observed across all helminth species, as well as within the different helminth taxa (trematodes, cestodes, nematodes and acanthocephalans). Our results demonstrate that the parasite species known at any given point in time are not a random subset of existing species, but rather a biased subset with respect to the parasites' biological properties.


Parasitology ◽  
2001 ◽  
Vol 122 (4) ◽  
pp. 471-481 ◽  
Author(s):  
E. T. VALTONEN ◽  
K. PULKKINEN ◽  
R. POULIN ◽  
M. JULKUNEN

We used nestedness analysis to seek non-random patterns in the structure of component communities of metazoan parasites collected from 31 sympatric fish species from the northeastern Bothnian Bay, the most oligohaline area of the Baltic Sea. Only 8 marine parasite species were found among the 63 species recorded, although some marine fish species reproduce in the bay and others occasionally visit the area. Marine parasite species can utilize both freshwater and marine fish species as intermediate or final hosts, and marine fish can harbour freshwater parasite species. This exchange of parasite species between marine and freshwater fish has probably resulted from ecological factors acting over short time scales rather than from evolutionary processes acting over longer time; the key factor probably being the immediate presence of suitable intermediate and definitive hosts. Marine fish were expected to harbour species-poor parasite communities consisting mainly of generalists acquired from the sympatric freshwater fish species, which would result in a nested pattern among the different component communities. However, an anti-nested pattern was found in the component communities of metazoan parasites of fishes from the Bothnian Bay. A likely explanation for the observed pattern is that there are specialist parasite species, the majority of which are cestodes, in some of the freshwater fish species which otherwise have depauperate parasite communities.


Parasitology ◽  
2015 ◽  
Vol 143 (1) ◽  
pp. 114-122 ◽  
Author(s):  
ROBERT POULIN ◽  
ANNE A. BESSON ◽  
MATHIEU B. MORIN ◽  
HASEEB S. RANDHAWA

SUMMARYHost-parasite checklists are essential resources in ecological parasitology, and are regularly used as sources of data in comparative studies of parasite species richness across host species, or of host specificity among parasite species. However, checklists are only useful datasets if they are relatively complete, that is, close to capturing all host–parasite associations occurring in a particular region. Here, we use three approaches to assess the completeness of 25 checklists of metazoan parasites in vertebrate hosts from various geographic regions. First, treating checklists as interaction networks between a set of parasite species and a set of host species, we identify networks with a greater connectance (proportion of realized host–parasite associations) than expected for their size. Second, assuming that the cumulative rise over time in the number of known host–parasite associations in a region tends toward an asymptote as their discovery progresses, we attempt to extrapolate the estimated total number of existing associations. Third, we test for a positive correlation between the number of published reports mentioning an association and the time since its first record, which is expected because observing and reporting host–parasite associations are frequency-dependent processes. Overall, no checklist fared well in all three tests, and only three of 25 passed two of the tests. These results suggest that most checklists, despite being useful syntheses of regional host–parasite associations, cannot be used as reliable sources of data for comparative analyses.


2018 ◽  
Vol 285 (1874) ◽  
pp. 20172613 ◽  
Author(s):  
A. W. Park ◽  
M. J. Farrell ◽  
J. P. Schmidt ◽  
S. Huang ◽  
T. A. Dallas ◽  
...  

The distribution of parasites across mammalian hosts is complex and represents a differential ability or opportunity to infect different host species. Here, we take a macroecological approach to investigate factors influencing why some parasites show a tendency to infect species widely distributed in the host phylogeny (phylogenetic generalism) while others infect only closely related hosts. Using a database on over 1400 parasite species that have been documented to infect up to 69 terrestrial mammal host species, we characterize the phylogenetic generalism of parasites using standard effect sizes for three metrics: mean pairwise phylogenetic distance (PD), maximum PD and phylogenetic aggregation. We identify a trend towards phylogenetic specialism, though statistically host relatedness is most often equivalent to that expected from a random sample of host species. Bacteria and arthropod parasites are typically the most generalist, viruses and helminths exhibit intermediate generalism, and protozoa are on average the most specialist. While viruses and helminths have similar mean pairwise PD on average, the viruses exhibit higher variation as a group. Close-contact transmission is the transmission mode most associated with specialism. Most parasites exhibiting phylogenetic aggregation (associating with discrete groups of species dispersed across the host phylogeny) are helminths and viruses.


2018 ◽  
Vol 52 (4) ◽  
pp. 279-288 ◽  
Author(s):  
F. Bakaria ◽  
S. Belhaoues ◽  
N. Djebbari ◽  
M. Tahri ◽  
I. Ladjama ◽  
...  

Abstract The aim of the study was to examine metazoans parasite communities of European eels (Anguilla anguilla) in freshwater (Tonga Lake) and brackish water (El Mellah lagoon) in the northeast of Algeria. Six parasite taxa were collected: one monogenean, Pseudodactylogyrus sp.; two crustaceans, Ergasilus sp. and Argulus foliaceus; two nematodes, Cucullanus sp. and Anguillicola crassus; one cestode, Bothriocephalus claviceps. Th e most prevalent parasite taxa in freshwater were Pseudodactylogyrus sp., A. crassus and Bothriocephalus claviceps; whereas in the brackish water, eels were infected mainly with A. crassus. Th e characteristics of the parasite component community structure revealed low parasite species diversity and high dominance values in eels from the two localities. Both communities were dominated by a single parasite species: Tonga eels by the monogenean Pseudodactylogyrus sp. and El Mellah lagoon eels by the nematode A. crassus, verified by high Berger-Parker dominance values of 0.76 and 0.87 respectively.


2003 ◽  
Vol 24 (2) ◽  
pp. 155-184 ◽  
Author(s):  
Carolyn A. Kapinus ◽  
Michael P. Johnson

Using data from a 1980 national sample of married men and women, the analysis examines the utility of the family life cycle concept, employing as dependent variables constructs from Johnson’s conceptualization of commitment. They argue, in disagreement with two classic critiques of the family life cycle concept, that the predictive power of family life cycle is, for many dependent variables, quite independent of age or length of marriage. Their analyses demonstrate that, when using dependent variables one would expect to be related to the presence and ages of children, family life cycle remains a useful predictive tool.


2008 ◽  
Vol 41 (2) ◽  
pp. 437-460 ◽  
Author(s):  
Olena Nikolayenko

Abstract. Regime change in Eastern Europe affords an excellent opportunity for investigating linkages between age and politics in times of social turmoil. Using data from three waves of the World Values Survey, this paper explores life cycle, generational and period effects on protest potential in Yeltsin's Russia. The study finds that an individual's position in the life cycle is the strongest predictor of protest potential in the post-communist state. Furthermore, the analysis suggests that citizens socialized during periods of relative socioeconomic stability exhibit the highest protest potential under conditions of uncertainty characteristic of the transition period.Résumé. Les changements de régime en Europe de l'Est permettent d'examiner la relation complexe entre l'âge et la politique pendant les périodes d'instabilité sociale. S'appuyant sur les données de trois vagues du World Values Survey (sondage mondial sur les valeurs), cet article explore l'incidence du cycle de vie, de la génération et de la période sur le potentiel protestataire dans la Russie d'Eltsine. L'étude démontre que la position de l'individu dans le cycle de vie est le plus puissant facteur de prédiction du potentiel protestataire dans la société postcommuniste. En outre, les citoyens socialisés pendant des périodes de relative stabilité socio-économique présentent le potentiel protestataire le plus élevé dans des conditions d'incertitude caractéristiques de la période de transition.


2012 ◽  
Vol 46 (5) ◽  
pp. 8-14
Author(s):  
I. A. Akimov ◽  
O. P. Korzh

Ecological Characteristics of Varroa destructor (Parasitiformes, Varroidae) and Its Environmental Capacity as a Key Factor for Development of Varroosis Panzootia. Akimov I. A., Korzh O. P. - By means of formalized schematic models of relationship with hosts the varroa mite uniqueness as a parasite is shown. The life cycle of this species requires the change of a host species at different stages of their development and physiological states. Thus the mite parasitizes not only a separate bee but a whole hive. The fact that the whole hive but not a single bee dies during varroosis development supports this idea. The impetus for this type of parasitism is the relative constancy of the environment in the hive supported by bees even in winter. Exactly this fact causes high pathogenicity of the varroa for the honey bee and its control complexity.


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