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Robert Poulin - One of the best experts on this subject based on the ideXlab platform.
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Evolution, phylogenetic distribution and functional ecology of division of labour in Trematodes
BMC, 2019Co-Authors: Robert Poulin, Tsukushi Kamiya, Clément LagrueAbstract:Abstract Division of labour has evolved in many social animals where colonies consist of clones or close kin. It involves the performance of different tasks by morphologically distinct castes, leading to increased colony fitness. Recently, a form of division of labour has been discovered in Trematodes: clonal rediae inside the snail intermediate host belong either to a large-bodied reproductive caste, or to a much smaller and morphologically distinct ‘soldier’ caste which defends the colony against co-infecting Trematodes. We review recent research on this phenomenon, focusing on its phylogenetic distribution, its possible evolutionary origins, and how division of labour functions to allow Trematode colonies within their snail host to adjust to threats and changing conditions. To date, division of labour has been documented in 15 species from three families: Himasthlidae, Philophthalmidae and Heterophyidae. Although this list of species is certainly incomplete, the evidence suggests that division of labour has arisen independently more than once in the evolutionary history of Trematodes. We propose a simple scenario for the gradual evolution of division of labour in Trematodes facing a high risk of competition in a long-lived snail host. Starting with initial conditions prior to the origin of castes (size variation among rediae within a colony, size-dependent production of cercariae by rediae, and a trade-off between cercarial production and other functions, such as defence), maximising colony fitness (R 0) can lead to caste formation or the age-structured division of labour observed in some Trematodes. Finally, we summarise recent research showing that caste ratios, i.e. relative numbers of reproductive and soldier rediae per colony, become more soldier-biased in colonies exposed to competition from another Trematode species sharing the same snail, and also respond to other stressors threatening the host’s survival or the colony itself. In addition, there is evidence of asymmetrical phenotypic plasticity among individual caste members: reproductives can assume defensive functions against competitors in the absence of soldiers, whereas soldiers are incapable of growing into reproductives if the latter’s numbers are reduced. We conclude by highlighting future research directions, and the advantages of Trematodes as model systems to study social evolution
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host diversity and latitude drive Trematode diversity patterns in the european freshwater fauna
Global Ecology and Biogeography, 2011Co-Authors: David W Thieltges, Christian Hof, Martin Brändle, Roland Brandl, Matthias D Dehling, Robert PoulinAbstract:Aim We investigated the relationship between host and parasite diversity as well as latitudinal gradients in parasite diversity on a continental scale in European freshwater Trematodes. Location European freshwaters. Methods We extracted distributional data for 564 freshwater Trematodes across 25 biogeographical regions in Europe from the Limnofauna Europaea and used multiple regression analyses to test for correlations between the diversity of definitive (vertebrates) or first intermediate (gastropods) hosts and that of Trematodes, and for latitudinal gradients in Trematode diversity. In particular, we investigated patterns in beta diversity among latitudinal bands and between Trematode species that parasitize host groups with low (autogenic) and high (allogenic) dispersal capacity. We also tested for a latitudinal gradient in the proportional representation of these two Trematode groups within regional faunas. Results Latitude or first intermediate host richness had no effect on Trematode richness, but definitive host richness was a strong predictor of Trematode richness, among both allogenic and autogenic parasites. We found that beta diversity of Trematode faunas within latitudinal bands decreased to the north, with similar values for allogenic and autogenic Trematodes. Finally, we observed an increasing proportion of autogenic species toward the north of Europe. Main conclusions The richness of definitive hosts appears to be the driver of Trematode diversity at a continental scale. The latitudinal gradient in beta diversity reflects patterns observed in free-living species and probably results from recolonization in the aftermath of the ice ages. The similar beta-diversity patterns of allogenic and autogenic Trematodes and the increasing proportion of autogenic Trematodes with increasing latitude are surprising. We suggest that the geographical scale of our analysis or confounding factors such as differences in habitat utilization and specialization may partly explain these patterns.
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small worms big appetites ratios of different functional morphs in relation to interspecific competition in Trematode parasites
International Journal for Parasitology, 2011Co-Authors: Tommy L F Leung, Robert PoulinAbstract:Animals living in colonies or collectives composed of highly-related individuals often produce morphs that are physically and behaviourally specialised to perform specific tasks. Because such morphs are often sterile, their production represents a fitness cost for the colony and there should be an optimal ratio of the numbers of sterile specialists and reproductive members that may be adjustable to environmental conditions. Trematode parasites undergo asexual multiplication within their snail intermediate host, resulting in large numbers of clonal stages known as rediae or sporocysts, depending on the Trematode species. In areas with high prevalences of infection, the host can be infected by multiple species, which can lead to intense competition for limited resources. Here, we describe the existence of specialised ‘mini-rediae’ in the Trematode Philophthalmus sp. that are morphologically and functionally specialised for interspecific competition. Mini-rediae were observed feeding on the sporocysts of a co-occurring Trematode species – Maritrema novaezealandensis. In addition, in larger snails – which are less likely to have M. novaezealandensis infections – Philophthalmus sp. produces relatively fewer mini-rediae than expected. Our findings support results from a prior study which demonstrated the existence of morphs that perform specialised functions in antagonistic interspecific interactions in Trematodes, and additionally shows that the number of these morphs in each host is associated with the likelihood of encountering other species within the same host. Trematodes may thus provide interesting models for studying morphological specialisation in colonial organisms.
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PAPER Host diversity and latitude drive Trematode diversity patterns in the
2011Co-Authors: David W Thieltges, Christian Hof, D. Matthias Dehling, Martin Brändle, Roland Brandl, Robert PoulinAbstract:Aim We investigated the relationship between host and parasite diversity as well as latitudinal gradients in parasite diversity on a continental scale in European freshwater Trematodes. Location European freshwaters. Methods We extracted distributional data for 564 freshwater Trematodes across 25 biogeographical regions in Europe from the Limnofauna Europaea and used multiple regression analyses to test for correlations between the diversity of definitive (vertebrates) or first intermediate (gastropods) hosts and that of Trematodes, and for latitudinal gradients in Trematode diversity. In particular, we investigated patterns in beta diversity among latitudinal bands and between Trematode species that parasitize host groups with low (autogenic) and high (allogenic) dispersal capacity. We also tested for a latitudinal gradient in the proportional representation of these two Trematode groups within regional faunas. Results Latitude or first intermediate host richness had no effect on Trematode richness, but definitive host richness was a strong predictor of Trematode richness, among both allogenic and autogenic parasites. We found that beta diversity of Trematode faunas within latitudinal bands decreased to the north, with similar values for allogenic and autogenic Trematodes. Finally, we observed an increasing proportion of autogenic species toward the north of Europe. Main conclusions The richness of definitive hosts appears to be the driver of Trematode diversity at a continental scale. The latitudinal gradient in beta diversity reflects patterns observed in free-living species and probably results from recolonization in the aftermath of the ice ages. The similar beta-diversity patterns of allogenic and autogenic Trematodes and the increasing proportion of autogenic Trematodes with increasing latitude are surprising. We suggest that the geographical scale of our analysis or confounding factors such as differences in habitat utilization and specialization may partly explain these patterns.
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Trematode parasites of otago harbour new zealand soft sediment intertidal ecosystems life cycles ecological roles and dna barcodes
New Zealand Journal of Marine and Freshwater Research, 2009Co-Authors: Tommy L F Leung, Devon B. Keeney, Kirsten M Donald, Anson V Koehler, Robert C Peoples, Robert PoulinAbstract:Abstract Parasites, in particular Trematodes (Platyhelminthes: Digenea), play major roles in the population dynamics and community structure of invertebrates on soft‐sediment mudflats. Here, we provide a list of the 20 Trematode species currently known to infect molluscs, crustaceans and polychaetes from Otago Harbour (New Zealand) soft‐sediment intertidal areas, as well as information on their transmission modes, life cycles, andknown ecological impacts. Several of the host‐parasite species combinations recorded here are reported for the first time. We also provide DNA barcodes, based on sequences of the cytochrome oxidase subunit l (CO1) gene, for 19 of the 20 Trematode species, to facilitate future identification of these parasites in marine ecological studies.
Dennis J. Minchella - One of the best experts on this subject based on the ideXlab platform.
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Snail-Trematode life history interactions: past trends and future directions.
Parasitology, 2001Co-Authors: Robert E. Sorensen, Dennis J. MinchellaAbstract:Life history traits expressed by organisms vary due to ecological and evolutionary constraints imposed by their current environmental conditions and genetic heritage. Trematodes often alter the life history of their host snails by inducing parasitic castration. Our understanding of the variables that influence the resulting changes in host growth, fecundity and survivorship is insufficient to confidently predict specific outcomes of novel snail-Trematode combinations. In a literature review of the last 30 years, we found 41 publications examining various life history characteristics of Trematode-infected snails. These publications reported 113 different field and laboratory experiments involving 30 snail species and 39 Trematode species and provided a data set for assessing factors that potentially affect life history outcomes. Analysis of the diverse responses across various snail-Trematode systems and experimental conditions teased out general patterns for the expression of host growth, fecundity and survival. These were used to address existing hypotheses and develop several new ones relating the response of snail-Trematode interactions to environmental and genetic factors. Finally, we propose directions for future experiments that will better assess the ecological and evolutionary factors influencing snail life history responses to Trematode parasitism.
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Snail–Trematode life history interactions: past trends and future directions
Parasitology, 2001Co-Authors: Robert E. Sorensen, Dennis J. MinchellaAbstract:Life history traits expressed by organisms vary due to ecological and evolutionary constraints imposed by their current environmental conditions and genetic heritage. Trematodes often alter the life history of their host snails by inducing parasitic castration. Our understanding of the variables that influence the resulting changes in host growth, fecundity and survivorship is insufficient to confidently predict specific outcomes of novel snail–Trematode combinations. In a literature review of the last 30 years, we found 41 publications examining various life history characteristics of Trematode-infected snails. These publications reported 113 different field and laboratory experiments involving 30 snail species and 39 Trematode species and provided a data set for assessing factors that potentially affect life history outcomes. Analysis of the diverse responses across various snail–Trematode systems and experimental conditions teased out general patterns for the expression of host growth, fecundity and survival. These were used to address existing hypotheses and develop several new ones relating the response of snail-Trematode interactions to environmental and genetic factors. Finally, we propose directions for future experiments that will better assess the ecological and evolutionary factors influencing snail life history responses to Trematode parasitism.
Robert E. Sorensen - One of the best experts on this subject based on the ideXlab platform.
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Snail-Trematode life history interactions: past trends and future directions.
Parasitology, 2001Co-Authors: Robert E. Sorensen, Dennis J. MinchellaAbstract:Life history traits expressed by organisms vary due to ecological and evolutionary constraints imposed by their current environmental conditions and genetic heritage. Trematodes often alter the life history of their host snails by inducing parasitic castration. Our understanding of the variables that influence the resulting changes in host growth, fecundity and survivorship is insufficient to confidently predict specific outcomes of novel snail-Trematode combinations. In a literature review of the last 30 years, we found 41 publications examining various life history characteristics of Trematode-infected snails. These publications reported 113 different field and laboratory experiments involving 30 snail species and 39 Trematode species and provided a data set for assessing factors that potentially affect life history outcomes. Analysis of the diverse responses across various snail-Trematode systems and experimental conditions teased out general patterns for the expression of host growth, fecundity and survival. These were used to address existing hypotheses and develop several new ones relating the response of snail-Trematode interactions to environmental and genetic factors. Finally, we propose directions for future experiments that will better assess the ecological and evolutionary factors influencing snail life history responses to Trematode parasitism.
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Snail–Trematode life history interactions: past trends and future directions
Parasitology, 2001Co-Authors: Robert E. Sorensen, Dennis J. MinchellaAbstract:Life history traits expressed by organisms vary due to ecological and evolutionary constraints imposed by their current environmental conditions and genetic heritage. Trematodes often alter the life history of their host snails by inducing parasitic castration. Our understanding of the variables that influence the resulting changes in host growth, fecundity and survivorship is insufficient to confidently predict specific outcomes of novel snail–Trematode combinations. In a literature review of the last 30 years, we found 41 publications examining various life history characteristics of Trematode-infected snails. These publications reported 113 different field and laboratory experiments involving 30 snail species and 39 Trematode species and provided a data set for assessing factors that potentially affect life history outcomes. Analysis of the diverse responses across various snail–Trematode systems and experimental conditions teased out general patterns for the expression of host growth, fecundity and survival. These were used to address existing hypotheses and develop several new ones relating the response of snail-Trematode interactions to environmental and genetic factors. Finally, we propose directions for future experiments that will better assess the ecological and evolutionary factors influencing snail life history responses to Trematode parasitism.
Thomas H. Cribb - One of the best experts on this subject based on the ideXlab platform.
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Trematode families and genera: have we found them all?
Trends in parasitology, 2011Co-Authors: Thomas H. Cribb, Rodney A BrayAbstract:The proposal of new Trematode families has almost stopped. Many new genera are still being proposed, but the number has fallen below historical rates. For most of the history of description of Trematodes there have been more genera known from tetrapods than from fishes, but this pattern has reversed recently. These reductions are argued to be more of a reflection of the law of diminishing returns than diminution of effort. Thus, at the family level the classification of Trematodes is becoming mature, and at the genus level we are seeing the ‘beginning of the end’ of the discovery of diversity. However, work for generations of scientists remains in other aspects of Trematode biodiversity research, especially in life cycles, phylogeny and biogeography.
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the Trematodes of groupers serranidae epinephelinae knowledge nature and evolution
Parasitology, 2002Co-Authors: Thomas H. Cribb, T Wright, Rodney A Bray, Sylvie PichelinAbstract:Groupers (Epinephelinae) are prominent marine fishes distributed in the warmer waters of the world. Review of the literature suggests that Trematodes are known from only 62 of the 159 species and only 9 of 15 genera; nearly 90% of host-parasite combinations have been reported only once or twice. All 20 families and all but 7 of 76 genera of Trematodes found in epinephelines also occur in non-epihephelines. Only 12 genera of Trematodes are reported from both the Atlantic-Eastern Pacific and the Indo-West Pacific. Few (perhaps no) species are credibly cosmopolitan but some have wide distributions across the Indo-West Pacific. The hierarchical 'relatedness' of epinephelines as suggested by how they share Trematode taxa (families, genera, species) shows little congruence with what is known of their phylogeny. The major determinant of relatedness appears to be geographical proximity. Together these attributes suggest that host-parasite coevolution has contributed little to the evolution of Trematode communities of epinephelines. Instead, they appear to have arisen through localized episodes of host-switching, presumably both into and out of the epinephelines. The Epinephelinae may well be typical of most groups of marine fishes both in the extent to which their Trematode parasites are known and in that, apparently, co-evolution has contributed little to the evolution of their communities of Trematodes.
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Trematode life cycles: short is sweet?
Trends in parasitology, 2002Co-Authors: Robert Poulin, Thomas H. CribbAbstract:Complex life cycles are a hallmark of parasitic Trematodes. In several Trematode taxa, however, the life cycle is truncated: fewer hosts are used than in a typical three-host cycle, with fewer transmission events. Eliminating one host from the life cycle can be achieved in at least three different ways. Some Trematodes show even more extreme forms of life cycle abbreviations, using only a mollusc to complete their cycle, with or without sexual reproduction. The occurrence of these phenomena among Trematode families are reviewed here and show that life cycle truncation has evolved independently many times in the phylogeny of Trematodes. The hypotheses proposed to account for life-cycle truncation, in addition to the factors preventing the adoption of shorter cycles by all Trematodes are also discussed. The study of shorter life cycles offers an opportunity to understand the forces shaping the evolution of life cycles in general.
David W Thieltges - One of the best experts on this subject based on the ideXlab platform.
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host diversity and latitude drive Trematode diversity patterns in the european freshwater fauna
Global Ecology and Biogeography, 2011Co-Authors: David W Thieltges, Christian Hof, Martin Brändle, Roland Brandl, Matthias D Dehling, Robert PoulinAbstract:Aim We investigated the relationship between host and parasite diversity as well as latitudinal gradients in parasite diversity on a continental scale in European freshwater Trematodes. Location European freshwaters. Methods We extracted distributional data for 564 freshwater Trematodes across 25 biogeographical regions in Europe from the Limnofauna Europaea and used multiple regression analyses to test for correlations between the diversity of definitive (vertebrates) or first intermediate (gastropods) hosts and that of Trematodes, and for latitudinal gradients in Trematode diversity. In particular, we investigated patterns in beta diversity among latitudinal bands and between Trematode species that parasitize host groups with low (autogenic) and high (allogenic) dispersal capacity. We also tested for a latitudinal gradient in the proportional representation of these two Trematode groups within regional faunas. Results Latitude or first intermediate host richness had no effect on Trematode richness, but definitive host richness was a strong predictor of Trematode richness, among both allogenic and autogenic parasites. We found that beta diversity of Trematode faunas within latitudinal bands decreased to the north, with similar values for allogenic and autogenic Trematodes. Finally, we observed an increasing proportion of autogenic species toward the north of Europe. Main conclusions The richness of definitive hosts appears to be the driver of Trematode diversity at a continental scale. The latitudinal gradient in beta diversity reflects patterns observed in free-living species and probably results from recolonization in the aftermath of the ice ages. The similar beta-diversity patterns of allogenic and autogenic Trematodes and the increasing proportion of autogenic Trematodes with increasing latitude are surprising. We suggest that the geographical scale of our analysis or confounding factors such as differences in habitat utilization and specialization may partly explain these patterns.
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PAPER Host diversity and latitude drive Trematode diversity patterns in the
2011Co-Authors: David W Thieltges, Christian Hof, D. Matthias Dehling, Martin Brändle, Roland Brandl, Robert PoulinAbstract:Aim We investigated the relationship between host and parasite diversity as well as latitudinal gradients in parasite diversity on a continental scale in European freshwater Trematodes. Location European freshwaters. Methods We extracted distributional data for 564 freshwater Trematodes across 25 biogeographical regions in Europe from the Limnofauna Europaea and used multiple regression analyses to test for correlations between the diversity of definitive (vertebrates) or first intermediate (gastropods) hosts and that of Trematodes, and for latitudinal gradients in Trematode diversity. In particular, we investigated patterns in beta diversity among latitudinal bands and between Trematode species that parasitize host groups with low (autogenic) and high (allogenic) dispersal capacity. We also tested for a latitudinal gradient in the proportional representation of these two Trematode groups within regional faunas. Results Latitude or first intermediate host richness had no effect on Trematode richness, but definitive host richness was a strong predictor of Trematode richness, among both allogenic and autogenic parasites. We found that beta diversity of Trematode faunas within latitudinal bands decreased to the north, with similar values for allogenic and autogenic Trematodes. Finally, we observed an increasing proportion of autogenic species toward the north of Europe. Main conclusions The richness of definitive hosts appears to be the driver of Trematode diversity at a continental scale. The latitudinal gradient in beta diversity reflects patterns observed in free-living species and probably results from recolonization in the aftermath of the ice ages. The similar beta-diversity patterns of allogenic and autogenic Trematodes and the increasing proportion of autogenic Trematodes with increasing latitude are surprising. We suggest that the geographical scale of our analysis or confounding factors such as differences in habitat utilization and specialization may partly explain these patterns.
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production of marine Trematode cercariae a potentially overlooked path of energy flow in benthic systems
Marine Ecology Progress Series, 2008Co-Authors: David W Thieltges, Janet Koprivnikar, Xavier De Montaudouin, Brian L Fredensborg, Thomas K Jensen, Robert PoulinAbstract:Parasites, in particular Trematodes, are unseen but ubiquitous components of marine intertidal ecosystems. Although parasites are known to affect population dynamics and food web structure, their potential function as an unrecognized path of energy flow in these ecosystems is yet to be quantified. We use published data on rates at which Trematodes produce free-swimming infec- tive larvae (cercariae) that are released from their gastropod intermediate hosts to investigate patterns in cercarial output as a function of different variables, and to calculate the annual produc- tion of cercariae in different marine benthic systems. Across 18 Trematode species, cercarial output (no. cercariae shed snail -1 d -1 ) ranged over 4 orders of magnitude and was positively correlated with snail host species size. While cercarial output did not correlate with latitude, it did correlate nega- tively with the size of cercariae, and was influenced by the type of downstream host sought by cer- cariae, being highest when this host was a vertebrate. Our estimates of annual cercarial production (kJ m -2 yr -1 ), which take into account the density of infected snails in the habitat, were within the range of production values reported for free-living invertebrates inhabiting benthic ecosystems. These estimates would be much higher if they included all Trematode species in an ecosystem, and not just single-species values. Overall, results suggest that Trematode cercariae represent potentially important paths of energy flow in benthic systems as well as a potentially important food supply to benthic organisms.
