@article {96285, title = {The Diversity of Parasites}, journal = {The Quarterly Review of Biology }, volume = {75}, year = {2000}, month = {Sep-01-2000}, pages = {277-293}, abstract = {

Parasitism is one of the most successful modes of life displayed by living organisms, as measured by how often it evolved and how many parasitic species are presently in existence. Studying the diversity of parasites is particularly relevant because sympatric diversification may be important in some parasite taxa, and because of the opportunity for independent tests of evolutionary hypotheses in the many separate lineages in which parasitism evolved. Our incomplete knowledge of existing parasite species--the result of a range of phenomena that includes inadequate sampling effort or the lumping of different cryptic species under one name--is not always a major obstacle for the study of parasite diversity. Patterns in the diversity of parasites may be associated with either host or parasite characteristics. The distribution of parasite diversity among host taxa does not simply reflect the species diversity of the host taxa themselves; life history and ecological traits of hosts appear to play important roles. These may determine the likelihood that hosts are colonized by parasite species over evolutionary time. It is not yet clear whether some host traits also favor intrahost speciation and diversification of parasites, and the formation of new parasite species. Certain features of parasites may also be associated with speciation and diversification. Only parasite body size has received much attention; the patterns observed are not greatly different from those of free-living species, with small-bodied parasite taxa being more speciose than related large-bodied taxa. Epidemiological parameters such as the basic reproductive rate of parasites, or R0, can also generate predictions regarding the distribution or evolution of parasite diversity. For instance, parasite taxa characterized by high R0 values may be more speciose than related taxa with lower values of R0; such predictions remain untested. Large-scale biogeographical patterns of diversity have only been well studied for metazoan parasites of marine fish; for these parasites, latitudinal patterns can be explained by effects of temperature on speciation rates and epidemiological variables, though other causes are possible. The emphasis for future research must shift from pattern description to the elucidation of the processes responsible for the structure and diversity of parasite faunas. A better integration of ecological and historical (or phylogenetic) approaches to the study of parasite diversity should make this objective possible.

}, issn = {0033-5770, 1539-7718}, doi = {10.1086/393500}, url = {https://www.journals.uchicago.edu/doi/10.1086/393500}, author = {R. Poulin and Serge Morand} } @inbook {96284, title = {The Many Roads to Parasitism}, booktitle = {Advances in Parasitology}, volume = {74}, year = {2011}, pages = {1-40}, publisher = {Elsevier}, organization = {Elsevier}, chapter = {1}, abstract = {

Parasitic organisms account for a large portion of living species. They have arisen on multiple independent occasions in many phyla, and thus encompass a huge biological diversity. This review uses several lines of evidence to argue that this vast diversity can be reduced to a few evolutionary end points that transcend phylogenetic boundaries. These represent peaks in the adaptive landscape reached independently by different lineages undergoing convergent evolution. Among eukaryotic parasites living in or on animals, six basic parasitic strategies are identified based on the number of hosts used per parasite generation, the fitness loss incurred by the host, and the transmission routes used by the parasites. They are parasitoids, parasitic castrators, directly transmitted parasites, trophically transmitted parasites, vector-transmitted parasites and micropredators. These show evidence of convergence in morphology, physiology, reproduction, life cycles and transmission patterns. Parasite\–host body size ratios, and the relationship between virulence and intensity of infection, are also associated with the different parasitic strategies, but not consistently so. At the population level, patterns of parasite distribution among hosts are not uniform across all parasitic strategies, but are distinctly different for parasitoids and castrators than for other parasites. To demonstrate that the above six strategies defined for animal parasites are universal, comparisons are made with parasites of plants, in particular, plant\–parasitic nematodes and parasitic angiosperms; these are shown to follow the same evolutionary trajectories seen among animal parasites, despite huge physiological and ecological differences between animals and plants. Beyond demonstrating the inevitable convergence of disparate lineages across biological hyperspace towards a limited set of adaptive strategies, this synthesis also provides a unifying framework for the study of parasitism.

}, issn = {0065-308X}, doi = {10.1016/b978-0-12-385897-9.00001-x}, url = {https://www.sciencedirect.com/science/article/abs/pii/B978012385897900001X}, author = {R. Poulin} } @article {96023, title = {A broadscale analysis of host-symbiont cophylogeny reveals the drivers of phylogenetic congruence}, journal = {congruent, evolution, host-switch transmission, incongruent, meta-analysis, mutualism, parasitism, phylogeny, symbiosis, tree}, volume = {24}, year = {2021}, month = {May-14-2021}, pages = {1681-1696}, abstract = {

Symbioses exert substantial biological influence, with great evolutionary and ecological relevance for disease, major evolutionary transitions, and the structure and function of ecological communities. Yet, much remains unknown about the patterns and processes that characterise symbioses. A major unanswered question is the extent to which symbiont phylogenies mirror those of their hosts and if patterns differ for parasites and mutualists. Addressing this question offers fundamental insights into evolutionary processes, such as whether symbionts typically codiverge with their hosts or if diversity is generated via host switches. Here, we perform a meta-analysis of host-symbiont phylogenetic congruence, encompassing 212 host-symbiont cophylogenetic studies that include ~10,000 species. Our analysis supersedes previous qualitative assessments by utilising a quantitative framework. We show that symbiont phylogeny broadly reflects host phylogeny across biodiversity and life-history, demonstrating a general pattern of phylogenetic congruence in host-symbiont interactions. We reveal two key aspects of symbiont life-history that promote closer ties between hosts and symbionts: vertical transmission and mutualism. Mode of symbiosis and mode of transmission are intimately interlinked, but vertical transmission is the dominant factor. Given the pervasiveness of symbioses, these findings provide important insights into the processes responsible for generating and maintaining the Earth\&$\#$39;s rich biodiversity.

Supporting Information: https://onlinelibrary.wiley.com/action/downloadSupplement?doi=10.1111\%2Fele.13757\&file=ele13757-sup-0001-Supinfo.html

}, issn = {1461-023X, 1461-0248}, doi = {10.1111/ele.13757}, url = {https://onlinelibrary.wiley.com/doi/full/10.1111/ele.13757}, author = {Alexander Hayward and R. Poulin and Shinichi Nakagawa} } @article {95983, title = {Considering Extinction of Dependent Species during Translocation, Ex Situ Conservation, and Assisted Migration of Threatened Hosts}, journal = {Conservation Biology}, volume = {26}, year = {2012}, month = {Mar-23-2012}, pages = {199-207}, type = {Essay}, abstract = {

Translocation, introduction, reintroduction, and assisted migrations are species conservation strategies that are attracting increasing attention, especially in the face of climate change. However, preventing the extinction of the suite of dependent species whose host species are threatened is seldom considered, and the effects on dependent species of moving threatened hosts are unclear. There is no published guidance on how to decide whether to move species, given this uncertainty. We examined the dependent\–host system of 4 disparate taxonomic groups: insects on the feather-leaf banksia (Banksia brownii), montane banksia (B. montana), and Stirling Range beard heath (Leucopogon gnaphalioides); parasites of wild cats; mites and ticks on Duvaucel\&$\#$39;s gecko (Hoplodactylus duvaucelii) and tuatara (Sphenodon punctatus); and internal coccidian parasites of Cirl Bunting (Emberiza cirlus) and Hihi (Notiomystis cincta). We used these case studies to demonstrate a simple process for use in species- and community-level assessments of efforts to conserve dependents with their hosts. The insects dependent on Stirling Range beard heath and parasites on tigers (Panthera tigris) appeared to represent assemblages that would not be conserved by ex situ host conservation. In contrast, for the cases of dependent species we examined involving a single dependent species (internal parasites of birds and the mite Geckobia naultina on Duvaucel\&$\#$39;s gecko), ex situ conservation of the host species would also conserve the dependent species. However, moving dependent species with their hosts may be insufficient to maintain viable populations of the dependent species, and additional conservation strategies such as supplementing populations may be needed.

Supporting document COBI_1826_sm_Appendix_S1.docx

}, keywords = {assisted colonization, coextinction conservation planning, Extinction risk, introductions, managed relocation, parasites, plant{\textendash}insect interactions, translocation}, issn = {0888-8892}, doi = {10.1111/j.1523-1739.2012.01826.x}, url = {https://conbio.onlinelibrary.wiley.com/doi/10.1111/j.1523-1739.2012.01826.x}, author = {Melinda L. Moir and Peter A. Vesk and Karl E.C. Brennan and R. Poulin and Lesley Hughes and David A. Keith and Michael A. McCarthy and David J. Coates} } @article {94735, title = {Checklist of marine mammal parasites in New Zealand and Australian waters}, journal = {Journal of Helminthology}, volume = {93}, year = {2019}, month = {Jan-11-2019}, pages = {649 - 676}, abstract = {

Marine mammals are long-lived top predators with vagile lifestyles, which often inhabit remote environments. This is especially relevant in the oceanic waters around New Zealand and Australia where cetaceans and pinnipeds are considered as vulnerable and often endan- gered due to anthropogenic impacts on their habitat. Parasitism is ubiquitous in wildlife, and prevalence of parasitic infections as well as emerging diseases can be valuable bioindicators of the ecology and health of marine mammals. Collecting information about parasite diversity in marine mammals will provide a crucial baseline for assessing their impact on host and eco- system ecology. New studies on marine mammals in New Zealand and Australian waters have recently added to our knowledge of parasite prevalence, life cycles and taxonomic relation- ships in the Australasian region, and justify a first host\–parasite checklist encompassing all available data. The present checklist comprises 36 species of marine mammals, and 114 spe- cies of parasites (helminths, arthropods and protozoans). Mammal species occurring in New Zealand and Australian waters but not included in the checklist represent gaps in our knowl- edge. The checklist thus serves both as a guide for what information is lacking, as well as a practical resource for scientists working on the ecology and conservation of marine mammals.

}, keywords = {Arctophoca australis forsteri}, issn = {0022-149X}, doi = {10.1017/S0022149X19000361}, url = {https://www.cambridge.org/core/product/identifier/S0022149X19000361/type/journal_article}, author = {Kristina Lehnert and R. Poulin and Bronwen Presswell} } @article {48020, title = {Speciation in parasites: a population genetics approach}, journal = {Trends in Parasitology}, volume = {21}, year = {2005}, month = {2005}, pages = {469 - 475}, abstract = {

Parasite speciation and host\–parasite coevolution should be studied at both macroevolutionary and microevolutionary levels.Studies on amacroevolutionary scale provide an essential framework for understanding the origins of parasite lineages and the patterns of diversification. However, because coevolutionary interactions can be highly divergent across time and space,it is important to quantify and compare the phylogeographic variation in both the host and the parasite throughout their geographical range. Furthermore, to evaluate demographic parameters that are relevant to population genetics structure, such as effective population size and parasite transmission, parasite populations must be studied using neutral genetic markers. Previous emphasis on larger-scale studies means that the connection between microevolutionary and macroevolutionary events is poorly explored. In this article, we focus on the spatial fragmentation of parasites and the population genetics processes behind their diversification in an effort to bridge the micro- and macro-scales.

}, doi = {https://doi.org/10.1016/j.pt.2005.08.009}, url = {https://www.sciencedirect.com/science/article/pii/S1471492205002205?via\%3Dihub}, author = {Huyse,Tine and R. Poulin and Th{\'e}ron,Andr{\'e}} } @article {47990, title = {Diversification of ectoparasite assemblages and climate: an example with fleas parasitic on small mammals}, journal = {Global Ecology and Biogeography}, volume = {14}, year = {2005}, month = {2005}, pages = {167 - 175}, abstract = {

We studied the relationships between the numbers of species and numbers of higher taxa (genera, tribes, subfamilies and families) in flea assemblages of small mammalian hosts with the aims of: (a) comparing these relationships across different regions, and (b) testing the hypothesis that flea assemblages in warmer regions diversify mainly via intrahost speciation, whereas those in colder regions diversify mainly via host switching.

Location The study used previously published data on flea assemblages on small mammalian hosts from 25 different regions of the Holarctic.

Methods The number of flea genera, tribes, subfamilies or families in an assemblage (host species) was plotted against the number of flea species in this assemblage for each region separately, and a power function was fitted to the resulting relationships. Then, the values of the exponent of the power function for a region were regressed against the mean annual temperature in this region, across all regions.

Results The relationships between the number of flea species and the numbers of flea genera, tribes, subfamilies or families on a host species in each region were found to be well described by simple power functions. The exponent of the power function of the relationship between the number of flea species and the number of flea genera per host tended to decrease with increasing local mean annual temperature. When two apparent outliers from the trend (corresponding to regions where sampling was not performed as in other regions) were omitted from the analysis, the negative relationship between temperature and the exponent of the power function between the number of flea species and number of flea genera per host became highly significant. No relationship was found between the values of the exponents of the power functions between the number of flea species and the number of flea tribes, subfamilies or families per host, and the mean local annual temperature.

Main conclusions The results suggest that the diversification of flea assemblages is associated with climatic variables. In warm regions, the greater number of congeneric species per flea assemblage, reflected by the lower exponent of the power function, may well be the outcome of intrahost speciation. This indicates that, as regional temperature increases, intrahost speciation becomes a relatively more important mode of diversification than acquisition of fleas via host switching.

}, doi = { https://doi.org/10.1111/j.1466-822X.2005.00146.x}, url = {https://onlinelibrary.wiley.com/doi/full/10.1111/j.1466-822X.2005.00146.x}, author = {Boris R. Krasnov and Shenbrot,Gregory I. and Irina S. Khokhlova and R. Poulin} } @article {47915, title = {Parasite manipulation of host behaviour: should hosts always lose?}, journal = {Oikos}, volume = {70}, year = {1994}, month = {1994}, pages = {479 - 484}, abstract = {

Parasites of all kinds alter the behaviour of their hosts. In many systems, these behavioural modifications appear adaptive for the parasite, by facilitating the completion of its life cycle. However, not all parasitized hosts are under the influence of parasites. This may be due to the timing of the onset of behavioural manipulation by the parasites: changes in behaviour may coincide with completed parasite development and only appear late in the infection. In addition, certain hosts may oppose the parasite\&$\#$39;s attempts at manipulating their behaviour. Hosts with high expected future reproductive success, i.e. young hosts or hosts that have not yet reproduced, are more likely to benefit by opposing the influence of parasites, as their expected gains would outweigh the costs of opposition. Such conditional opposition would be a better alternative to resistance to infection itself if resistance is costly, and would explain the considerable variability often observed in the behavioural responses of parasitized hosts. Future tests of these ideas should give insights into the coevolution of hosts and parasites and the parasites\&$\#$39; struggle for the control of host behaviour.

}, doi = {https://doi.org/10.2307/3545788}, url = {https://www.jstor.org/stable/3545788}, author = {R. Poulin and Jacques Brodeur and Moore,Janice} } @inbook {47795, title = {Blood-sucking lice (Anoplura) of small mammals: True parasites}, booktitle = {Micromammals and macroparasites: From evolutionary ecology to management}, year = {2006}, month = {2006}, pages = {141 - 160}, publisher = {Springer}, organization = {Springer}, address = {Tokyo, Japan}, url = {https://link.springer.com/chapter/10.1007/978-4-431-36025-4_9}, author = {Kim,Ke Chung}, editor = {Serge Morand and Boris R. Krasnov and R. Poulin} } @book {47790, title = {Evolutionary Ecology of Parasites}, year = {1998}, month = {1998}, publisher = {Chapman and Hall}, organization = {Chapman and Hall}, address = {London, England}, author = {R. Poulin} } @book {47791, title = {Evolutionary Ecology of Parasites}, volume = {2nd.}, year = {2007}, month = {2007}, publisher = {Princeton University Press}, organization = {Princeton University Press}, address = {Princeton, New Jersey}, author = {R. Poulin} } @article {45848, title = {Covariance in species diversity and facilitation among non-interactive parasite taxa: all against the host}, journal = {Parasitology}, volume = {131}, year = {2005}, month = {2005}, pages = {557 - 568}, abstract = {

Different parasite taxa exploit different host resources and are often unlikely to interact directly. It is unclear, however, whether the diversity of any given parasite taxon is indirectly influenced by that of other parasite taxa on the same host. Some components of host immune defences may operate simultaneously against all kinds of parasites, whereas investment by the host in specific defences against one type of parasite may come at the expense of defence against other parasites. We investigated the relationships between the species diversity of 4 higher taxa of ectoparasites (fleas, sucking lice, mesostigmatid mites, and ixodid ticks), and between the species richness of ectoparasites and endoparasitic helminths, across different species of rodent hosts. Our analyses used 2 measures of species diversity, species richness and taxonomic distinctness, and controlled for the potentially confounding effects of sampling effort and phylogenetic relationships among host species. We found positive pairwise correlations between the species richness of fleas, mites and ticks; however, there was no association between species richness of any of these 3 groups and that of lice. We also found a strong positive relationship between the taxonomic distinctness of ecto- and endoparasite assemblages across host species. These results suggest the existence of a process of apparent facilitation among unrelated taxa in the organization of parasite communities. We propose explanations based on host immune responses, involving acquired cross-resistance to infection and interspecific variation in immunocompetence among hosts, to account for these patterns.

}, doi = {https://doi.org/10.1017/S0031182005007912}, url = {https://www.cambridge.org/core/journals/parasitology/article/covariance-in-species-diversity-and-facilitation-among-noninteractive-parasite-taxa-all-against-the-host/4B2444374E26E68E2485019A9CA914CB}, author = {Boris R. Krasnov and Mouillot,D. and Irina S. Khokhlova and Shenbrot,G. I. and R. Poulin} } @article {45199, title = {The disparity between observed and uniform distributions: A new look at parasite aggregation}, journal = {International Journal for Parasitology}, volume = {23}, year = {1993}, month = {1993}, pages = {937 - 944}, abstract = {

A simple new measure of parasite aggregation is described, the index of discrepancy (D). It quantifies the difference between the observed parasite distribution, and the hypothetical distribution that corresponds to the ideal case where all hosts harbour the same number of parasites. This index, computed for parasite distributions obtained from the literature, is compared to 2 other measures of aggregation, the variance to mean ratio and the parameter k of the negative binomial distribution. Both k and D indicate that aggregation decreases when the prevalence of infection and the mean number of parasites per host increase, while the variance to mean ratio suggests the opposite. Since an increase in prevalence means that parasites exploit a greater proportion of the available hosts and are thus not concentrating in only a few, aggregation should be inversely proportional to prevalence. Unlike k and D, the variance to mean ratio is a host-centered measure that is not very sensitive to the distribution of parasites. The index of discrepancy, on the other hand, is not only much easier to compute than k, but focuses on the difference between an ideal, uniform distribution and the one actually displayed by parasites. Since what it measures is what parasitologists mean by aggregation, the new index appears to be a more adequate measure of aggregation than other measures currently used.

}, doi = {https://doi.org/10.1016/0020-7519(93)90060-C}, url = {https://www.sciencedirect.com/science/article/abs/pii/002075199390060C}, author = {R. Poulin} } @article {45193, title = {Parasitism and grup size in social animals: A meta-analysis}, journal = {Behavioral Ecology}, volume = {6}, year = {1995}, month = {1995}, pages = {159 - 165}, abstract = {

The size of groups formed by social animals is thought to result from a combination of selection pressures acting on individuals to maximize their fitness. In addition to commonly-invoked selective agents (e.g., predation), a growing number of studies suggest that levels of parasitism may be related to host group size and that parasites may influence optimal group size. We used a meta-analysis to quantify die intraspecific association found in published studies between prevalence and intensity of parasitism and host group size in a variety of taxa. We considered separately contagious parasites, which are transmitted via contact with infected individuals or feces, and mobile parasites which do not need proximity among hosts for transmission. In addition to mode of transmission, host group mobility was examined as a potential correlate of die association. Consistent positive correlations were found between host group size and both the prevalence and intensity of contagious parasites. By contrast, the intensity of infection by mobile parasites consistendy decreased as host group size increased. Host group mobility had no apparent effect on either the strength or die direction of these correlations. Although few experimental studies examined the causal effect of parasitism on host group size, strong circumstantial evidence was provided, at least for mobile parasites, by many reports of larger host group sizes following increases in parasite abundance. Our results therefore suggest that parasites with different modes of transmission can exert conflicting selection on host group size. The trends found in the meta-analysis, however, do not hold in interspecific comparative studies, possibly owing to differences among related species in die relative importance of parasitism as a selective force.

}, doi = {https://doi.org/10.1093/beheco/6.2.159}, url = {https://academic.oup.com/beheco/article/6/2/159/184622}, author = {C{\^o}t{\'e},I. M. and R. Poulin} } @article {40408, title = {Parasite extinction and colonisation and the evolution of parasite communities: a simulation study}, journal = {International Journal for Parasitology}, volume = {28}, year = {1998}, month = {1998}, pages = {727 - 737}, abstract = {

We determined what evolutionary processes influence the likelihood of detecting an effect of host ecological characteristics on the richness of parasite communities in comparative analyses among related host species. We used a mathematical model to generate phylogenies of hosts in which parasite communities varied over evolutionary time as parasite species were either gained or lost during host speciation events. Gain or loss of parasites were stochastic and could either be strongly, moderately, weakly, or not, affected by host ecological characteristics. The model was evaluated over this range of effects of host ecology, and for various mean probabilities of parasite gain and loss and various rates of change in host ecological characteristics at speciation events. Our results suggest that phylogenetic effects (the passing of parasite species from mother to daughter host species) are likely to obscure ecological effects (the effect of host body size, diet, habitat, lifespan, etc.) except when the effects of host ecology are strong, and the probabilities of gain or loss of parasites are high, or host ecological characteristics change markedly at speciation events. This outcome was not influenced by the shape of the phylogenetic tree used in the simulations. Sensitivity analysis of our model also shows this result to be robust to a wide range of assumptions and parameter values. Thus, because the composition of parasite communities tends to reflect their ancestry, the effect of host ecology will often be very difficult to detect. (C) 1998 Australian Society for Parasitology. Published by Elsevier Science Ltd.

}, keywords = {analyses, assemblages, colonization, communities, comparative, cospeciation, ecology, extinction, fish, fresh water, Helminths, host, lice, parasite, Phylogeny, richness, simulations}, doi = {https://doi.org/10.1016/S0020-7519(98)00036-8}, url = {https://www.sciencedirect.com/science/article/abs/pii/S0020751998000368}, author = {Vickery,W. L. and R. Poulin} } @article {39594, title = {Group-living and infestation by ectoparasites in passerines}, journal = {Condor}, volume = {93}, year = {1991}, month = {1991}, pages = {418 - 423}, abstract = {

Using data from an 11-year field study, I determined whether group-living passerine species showed greater infestation by contact-transmitted ectoparasites (feather mites) than sympatric, solitary species. Differences in infestation by mobile hippoboscid flies between group-living and solitary passerine species were also examined. Among the 45 species included in the analysis, feather mite prevalence was significantly greater on group-living species than on solitary ones. Two other factors investigated, bird size and migratory habit, had no effect on infestation levels. Similar results were obtained when the analysis was performed on all species outside the most species-rich family (Fringillidae), or only within the family Fringillidae itself. An analysis at the family level also suggested greater feather mite infestations in families made up only of group-living species as opposed to families including only solitary species; however, the difference was not significant. No differences were observed in hippoboscid fly abundance between group-living and solitary passerines, in all analyses at either the species or family level. These results suggest that individuals of group-living species incur a greater risk of acquiring contact-transmitted ectoparasites than individuals of solitary species, a cost which may not be negligible.

}, doi = {https://doi.org/10.2307/1368958}, url = {https://academic.oup.com/condor/article-abstract/93/2/418/5185583?redirectedFrom=fulltext}, author = {R. Poulin} } @article {39604, title = {Phylogeny, ecology, and the richness of parasite communities}, journal = {Ecological Monographs}, volume = {65}, year = {1995}, month = {1995}, pages = {283 - 302}, abstract = {

The makeup of parasite communities is the result, among other factors, of interactions between the evolutionary history and ecological characteristics of hosts. This study evaluates the relative importance of some ecological factors (host body size, diet, habitat, latitude, and the mean number of parasite individuals per host) as determinants or correlates of parasite community richness in vertebrates, before and after controlling for potential effects of host phylogenetic relationships. Data were obtained from the literature on 596 parasite communities belonging to one of four distinct types: gastrointestinal parasite communities of fish, birds, or mammals, and ectoparasite communities of fish. There were positive correlations between the number of hosts sampled and mean species richness of the parasite community of each genus. In analyses treating host genera as independent statistical observations and using estimates of parasite species richness corrected for host sample size, positive correlations were observed between richness and host body size in gastrointestinal communities of all three groups of vertebrates. The mean number of parasite individuals per host also was correlated positively with species richness. In fish, richness increased with increases in the proportion of animal food in the host diet. Aquatic birds had richer parasite communities than their terrestrial counterparts, whereas marine fish had richer gastrointestinal parasite communities than freshwater fish. The richness of ectoparasite communities on fish showed no association with any of the ecological variables investigated. Using host genera as independent points in the analyses may lead to biased results since some host lineages are descended from recent common ancestors, and are therefore not truly independent. The comparative analysis was repeated using phylogenetically independent contrasts derived from the phylogeny of hosts. Once the effects of host phylogeny were removed, somewhat different results were obtained: host body size showed no relationship with parasite species richness in birds, and there was no evidence that habitat transitions resulted in significant changes in parasite species richness in any of the types of communities studied. Of the ecological factors studied, the comparative analyses suggest that only host body size can be an important determinant of parasite community richness in certain host groups. This study illustrates clearly the need to control for phylogeny in investigations of host-parasite interactions

}, url = {https://www.jstor.org/stable/2937061?seq=1$\#$metadata_info_tab_contents}, author = {R. Poulin} }