Recently, the World Health Organization recognized that efforts to interrupt schistosomiasis transmission through mass drug administration have been ineffective in some regions; one of their new recommended strategies for global... more
Recently, the World Health Organization recognized that efforts to interrupt schistosomiasis transmission through mass drug administration have been ineffective in some regions; one of their new recommended strategies for global schistosomiasis control emphasizes targeting the freshwater snails that transmit schistosome parasites. We sought to identify robust indicators that would enable precision targeting of these snails. At the site of the world’s largest recorded schistosomiasis epidemic—the Lower Senegal River Basin in Senegal—intensive sampling revealed positive relationships between intermediate host snails (abundance, density, and prevalence) and human urogenital schistosomiasis reinfection (prevalence and intensity in schoolchildren after drug administration). However, we also found that snail distributions were so patchy in space and time that obtaining useful data required effort that exceeds what is feasible in standard monitoring and control campaigns. Instead, we ident...
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Here, we present the results of a taxonomic survey of the nematodes parasitizing fishes from the lagoon flats of Palmyra Atoll, Eastern Indo-Pacific. We performed quantitative parasitological surveys of 653 individual fish from each of... more
Here, we present the results of a taxonomic survey of the nematodes parasitizing fishes from the lagoon flats of Palmyra Atoll, Eastern Indo-Pacific. We performed quantitative parasitological surveys of 653 individual fish from each of the 44 species using the intertidal sand flats that border the atoll’s lagoon. We provide morphological descriptions, prevalence, and mean intensities of the recovered seven species of adult nematode (Pulchrascaris chiloscyllii, Capillariidae gen. sp.,Cucullanus bourdini,Cucullanus oceaniensis,Pseudascarophissp., Spinitectus (Paraspinitectus) palmyraensissp. nov.,Philometra pellucida) and three larval stages (Pulchrascarissp.,Hysterothylaciumsp.,Cucullanussp.). We recorded:Pulchrascaris chiloscylliifromCarcharhinus melanopterus; Capillariidae gen. sp. fromChaetodon lunula,Lutjanus fulvus, andEllochelon vaigiensis;Cucullanus bourdinifromArothron hispidus;Cucullanus oceaniensisfromAbudefduf sordidus;Pseudascarophissp. fromChaetodon auriga,Chaetodon lunu...
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Schistosome parasites infect more than 200 million people annually, mostly in sub-Saharan Africa, where people may be co-infected with more than one species of the parasite. Infection risk for any single species is determined, in part, by... more
Schistosome parasites infect more than 200 million people annually, mostly in sub-Saharan Africa, where people may be co-infected with more than one species of the parasite. Infection risk for any single species is determined, in part, by the distribution of its obligate intermediate host snail. As the World Health Organization reprioritizes snail control to reduce the global burden of schistosomiasis, there is renewed importance in knowing when and where to target those efforts, which could vary by schistosome species. This study estimates factors associated with schistosomiasis risk in 16 villages located in the Senegal River Basin, a region hyperendemic for Schistosoma haematobium and S. mansoni. We first analyzed the spatial distributions of the two schistosomes’ intermediate host snails (Bulinus spp. and Biomphalaria pfeifferi, respectively) at village water access sites. Then, we separately evaluated the relationships between human S. haematobium and S. mansoni infections and ...
Research Interests: Biotechnology, Biology, Tropical Medicine, Ecology, Infectious Diseases, and 13 moreRare diseases, Medicine, Biological Sciences, Habitat, Digestive and Liver Diseases, Schistosomiasis, Infection, Snail, Vector borne diseases, Schistosoma Mansoni, Intermediate Host, Medical and Health Sciences, and Schistosoma Haematobium
Dicyemids and orthonectids were traditionally classified in a group called Mesozoa, but their placement in a single clade has been contested and their position(s) within Metazoa is uncertain. Here, we assembled a comprehensive matrix of... more
Dicyemids and orthonectids were traditionally classified in a group called Mesozoa, but their placement in a single clade has been contested and their position(s) within Metazoa is uncertain. Here, we assembled a comprehensive matrix of Lophotrochozoa (Metazoa) and investigated the position of Dicyemida (= Rhombozoa) and Orthonectida, employing multiple phylogenomic approaches. We sequenced seven new transcriptomes and one draft genome from dicyemids ( Dicyema , Dicyemennea ) and two transcriptomes from orthonectids ( Rhopalura ). Using these and published data, we assembled and analysed contamination-filtered datasets with up to 987 genes. Our results recover Mesozoa monophyletic and as a close relative of Platyhelminthes or Gnathifera. Because of the tendency of the long-branch mesozoans to group with other long-branch taxa in our analyses, we explored the impact of approaches purported to help alleviate long-branch attraction (e.g. taxon removal, coalescent inference, gene target...
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Plate 1.[See Figure 2 in Hrycaj & Popadiü.](A) A diagram depicting mandibular composition (whole limb versus limb base only).(B) Dissected adult mandibles of the pillbug, Armadillidium vulgare.(C) Dissected adult mandibles of the... more
Plate 1.[See Figure 2 in Hrycaj & Popadiü.](A) A diagram depicting mandibular composition (whole limb versus limb base only).(B) Dissected adult mandibles of the pillbug, Armadillidium vulgare.(C) Dissected adult mandibles of the firebrat, Thermobia domestica. In B and C, arrowheads point to dissected mandibular appendages.
Dicyemids and orthonectids were traditionally classified in a group called Mesozoa, but their placement in a single clade has been contested and their position(s) within Metazoa is uncertain. Here, we assembled a comprehensive matrix of... more
Dicyemids and orthonectids were traditionally classified in a group called Mesozoa, but their placement in a single clade has been contested and their position(s) within Metazoa is uncertain. Here, we assembled a comprehensive matrix of Lophotrochozoa (Metazoa) and investigated the position of Dicyemida (= Rhombozoa) and Orthonectida, employing multiple phylogenomic approaches. We sequenced seven new transcriptomes and one draft genome from dicyemids ( Dicyema , Dicyemennea ) and two transcriptomes from orthonectids ( Rhopalura ). Using these and published data, we assembled and analysed contamination-filtered datasets with up to 987 genes. Our results recover Mesozoa monophyletic and as a close relative of Platyhelminthes or Gnathifera. Because of the tendency of the long-branch mesozoans to group with other long-branch taxa in our analyses, we explored the impact of approaches purported to help alleviate long-branch attraction (e.g. taxon removal, coalescent inference, gene targeting). None of these were able to break the association of Orthonectida with Dicyemida in the maximum-likelihood trees. Contrastingly, the Bayesian analysis and site-specific frequency model in maximum-likelihood did not recover a monophyletic Mesozoa (but only when using a specific 50 gene matrix). The classic hypothesis on monophyletic Mesozoa is possibly reborn and should be further tested.
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The parasitic barnacles, Rhizocephala, are a little known group within Australia with only seven described species from a coastline stretching approximately 59763 km. This study describes a new species of Rhizocephala, Sacculina... more
The parasitic barnacles, Rhizocephala, are a little known group within Australia with only seven described species from a coastline stretching approximately 59763 km. This study describes a new species of Rhizocephala, Sacculina nectocarcini. The description is based on a unique combination of features pertaining to the structure of the mantle papillae, the retinaculae and the male receptacles. Biological notes, prevalence and intensity of infection are reported for this rhizocephalan, infesting the red rock crab, Nectocarcinus integrifrons, collected from Western Port, Victoria, Australia.
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We surveyed copepods parasitic on the fishes at Palmyra, a remote atoll in the Central Indo-Pacific faunal region. In total, we collected 849 individual fish, representing 44 species, from the intertidal lagoon flats at Palmyra and... more
We surveyed copepods parasitic on the fishes at Palmyra, a remote atoll in the Central Indo-Pacific faunal region. In total, we collected 849 individual fish, representing 44 species, from the intertidal lagoon flats at Palmyra and recovered 17 parasitic copepod species. The parasitic copepods were:OrbitacolaxwilliamsionMulloidichthysflavolineatus;AnuretesserratusonAcanthurusxanthopterus;CaligusconfususonCarangoidesferdau,Carangoidesorthogrammus,Caranxignobilis,Caranxmelampygus, andCaranxpapuensis;CaliguskapuhilionChaetodonaurigaandChaetodonlunula;CaliguslaticaudusonRhinecanthusaculeatus,Pseudobalistesflavimarginatus,M.flavolineatus,Upeneustaeniopterus,Chrysipteraglauca, andEpinephalusmerra;CaligusmutabilisonLutjanusfulvusandLutjanusmonostigma;CaligusrandallionC.ignobilis;Caligussp. onL.fulvus;CaritusserratusonChanoschanos;LepeophtheiruslewisionA.xanthopterus;LepeophtheirusuluusonC.ignobilis;DissonussimilisonArothronhispidus;Nemesissp. onCarcharhinusmelanopterus;Hatschekialongiabdom...
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AimTo improve our understanding of how parasitism interacts with geographical range expansions by quantifying diversity and abundance of parasites in 25 populations of a large marine snail, Kellet's whelk (Kelletia kelletii),... more
AimTo improve our understanding of how parasitism interacts with geographical range expansions by quantifying diversity and abundance of parasites in 25 populations of a large marine snail, Kellet's whelk (Kelletia kelletii), throughout its historical and recently expanded range, which are separated by a well‐known biogeographical boundary.LocationCalifornia coast (western North America).MethodsParasitological examinations were conducted on 199 whelks from 25 subtidal reefs throughout its expanded and historical ranges. We calculated infection risk, parasite intensity, and parasite species diversity. Abiotic (temperature, latitude, distance from range limit) and biotic (host density) variables were analysed as potential drivers of differential parasitism between expanded‐ and historical‐range populations.ResultsCompared with historical‐range whelks, expanded‐range whelks were 20% as likely to be infected by parasites, and those that were infected had 6% the number of individual ...
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Amphipods are often key species in aquatic food webs due to their functional roles in the ecosystem and as intermediate hosts for trophically transmitted parasites. Amphipods can also host many parasite species, yet few studies address... more
Amphipods are often key species in aquatic food webs due to their functional roles in the ecosystem and as intermediate hosts for trophically transmitted parasites. Amphipods can also host many parasite species, yet few studies address the entire parasite community of a gammarid population, precluding a more dynamic understanding of the food web. We set out to identify and quantify the parasite community of Gammarus lacustris to understand the contributions of the amphipod and its parasites to the Takvatn food web. We identified seven parasite taxa: a direct life cycle gregarine, Rotundula sp., and larval stages of two digenean trematode genera, two cestodes, one nematode, and one acanthocephalan. The larval parasites use either birds or fishes as final hosts. Bird parasites predominated, with trematode Plagiorchis sp. having the highest prevalence (69%) and mean abundance (2.7). Fish parasites were also common, including trematodes Crepidostomum spp., nematode Cystidicola farionis,...
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Introduced marine species are a major environmental and economic problem. The rate of these biological invasions has substantially increased in recent years due to the globalization of the world's economies. The damage caused by... more
Introduced marine species are a major environmental and economic problem. The rate of these biological invasions has substantially increased in recent years due to the globalization of the world's economies. The damage caused by invasive species is often a result of the higher densities and larger sizes they attain compared to where they are native. A prominent hypothesis explaining the success of introduced species is that they are relatively free of the effects of natural enemies. Most notably, they may encounter fewer parasites in their introduced range compared to their native range. Parasites are ubiquitous and pervasive in marine systems, yet their role in marine invasions is relatively unexplored. Although data on parasites of marine organisms exist, the extent to which parasites can mediate marine invasions, or the extent to which invasive parasites and pathogens are responsible for infecting or potentially decimating native marine species have not been examined. In this...
Research Interests: Parasitology, Biology, Ecology, Invasive Species, Medicine, and 14 moreAnimals, Parasites, Host-parasite interactions, Endemic Diseases, Seawater, Snails, Species Richness, Introduced species, Theoretical Models, Veterinary Sciences, Species Specificity, Food Chain, Marine ecosystem, and Marine Species
In some of the most complex animal societies, individuals exhibit a cooperative division of labour to form castes. The most pronounced types of caste formation involve reproductive and non-reproductive forms that are morphologically... more
In some of the most complex animal societies, individuals exhibit a cooperative division of labour to form castes. The most pronounced types of caste formation involve reproductive and non-reproductive forms that are morphologically distinct. In colonies comprising separate or mobile individuals, this type of caste formation has been recognized only among the arthropods, sea anemones and mole-rats. Here, we document physical and behavioural caste formation in a flatworm. Trematode flatworm parasites undergo repeated clonal reproduction of ‘parthenitae’ within their molluscan hosts forming colonies. We present experimental and observational data demonstrating specialization among trematode parthenitae to form distinct soldier and reproductive castes. Soldiers do not reproduce, have relatively large mouthparts, and are much smaller and thinner than reproductives. Soldiers are also more active, and are disproportionally common in areas of the host where invasions occur. Further, only s...
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This experiment, the last we ran under California Sea Grant project number R/CZ-162, was designed to test the settlement preferences of S. carcini under more natural conditions than in our previous experiments, which utilized 0.5 L... more
This experiment, the last we ran under California Sea Grant project number R/CZ-162, was designed to test the settlement preferences of S. carcini under more natural conditions than in our previous experiments, which utilized 0.5 L containers and cyprid densities ranging from 1-75 cyprids ml-1 (see Goddard et al. 2005). Mark Torchin designed the experiment and set up the exposure containers, which were nested in a flow-through system (with filtered outflow); Jeff Goddard and Mark Torchin examined crabs for cyprid settlement; Jeff Goddard dissected and examined crabs for infection by S. carcini.
We apply a Dynamic Energy Budget model to the common liver fluke (Fasciola hepatica), as well as its intermediate and final hosts. First, an introduction to the DEB theory is given. We divide the fluke's seven-stage life cycle into... more
We apply a Dynamic Energy Budget model to the common liver fluke (Fasciola hepatica), as well as its intermediate and final hosts. First, an introduction to the DEB theory is given. We divide the fluke's seven-stage life cycle into three phases and construct an independent model for each. We link DEB variables to measurable quantities like weight, glycogen content, and oxygen consumption, then find model parameters that match predictions to data from existing studies. We compare the present model to existing ...
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An ecological assessment of Fecampia erythrocephala, reporting its habitat distribution, abundance, host specificity, size-specific prevalence, frequency distribution among hosts, effect on host growth, and its site specificity within... more
An ecological assessment of Fecampia erythrocephala, reporting its habitat distribution, abundance, host specificity, size-specific prevalence, frequency distribution among hosts, effect on host growth, and its site specificity within these hosts is presented. At the Isle of Man and near Plymouth, Fecampia erythrocephala cocoons were generally abundant on the undersides of rocks in the Ascophyllum and Fucus serratus zones. Infected crabs were also most common in these habitats. Both Carcinus maenas and Cancer pagurus were parasitized at similar prevalences, although the former species was relatively much more common in the habitats where the worm cocoons were abundant. Fecampia erythrocephala did not infect crabs larger than 11 mm carapace width, and prevalence decreased significantly with crab size. Prevalences reached 11% in areas where cocoons were abundant. Together with the large size of these worms relative to the size of the host crabs and the observations on worm emergence, ...
Research Interests: Zoology, Plant Biology, Crustacea, Life history, Biology, and 8 moreEcology, Habitat, Man, Prevalence, Coastal Zone, Carcinus Maenas, Carapace Width, and Host
Abstract:“How healthy is that salt marsh?” Sea Grant biologists are examining certain kinds of parasites infecting marsh snails to answer this question. They have shown that the collection of parasites inside snails reflects the diversity... more
Abstract:“How healthy is that salt marsh?” Sea Grant biologists are examining certain kinds of parasites infecting marsh snails to answer this question. They have shown that the collection of parasites inside snails reflects the diversity of animal life at the marsh and hence can be used as an index of wetland health. Put simply: the more parasites in snails, the healthier the marsh.
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Thursday, August 6, 2009 - 7:20 PM Selective predation of Pachygrapsus crassipes and Hemigrapsus oregonensis on the California horn snail, Cerithidea californica in the laboratory. Maria Magdalena Meza-Lopez 1 , Julio ...
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Complex societies where individuals exhibit division of labor with physical polymorphism, behavioral specialization, and caste formation, have evolved several times throughout the animal kingdom. Recently, such complex sociality has been... more
Complex societies where individuals exhibit division of labor with physical polymorphism, behavioral specialization, and caste formation, have evolved several times throughout the animal kingdom. Recently, such complex sociality has been recognized in digenean trematodes; evidence is limited to six marine species. Hence, the extent to which a soldier caste is present throughout the Trematoda is sparsely documented, and there are no studies detailing the structure of a species lacking such a social structure. Here we examine colony structure for an additional five echinostomoid species, four of which infect the marine snail Cerithidea californica and one (Echinostoma liei) that infects the freshwater snail Biomphalaria glabrata. For all species, we present redia morphology (pharynx and body size), and the distribution of individuals of different castes throughout the snail body. When morphological evidence indicated the presence of a soldier caste, we assessed behavior by measuring attack rates of the different morphs toward heterospecific trematodes. Our findings indicate that each of the four species from C. californica have a permanent soldier caste, while E. liei does not. The observed intra- and interspecific variation of caste structure for those species with soldiers, and the documentation of colony structure for a species explicitly lacking permanent soldiers, emphasizes the diverse nature of trematode sociality and the promise of the group to permit comparative investigations of the evolution and ecology of sociality.
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Spinitectus gabata n. sp. (Spirurina: Cystidicolidae) from the gastrointestinal tract of an oarfish, Regalecus russelii, (Regalecidae), captured off the coast of Fukuoka Prefecture, Kyushu Island, Japan is the first nematode described... more
Spinitectus gabata n. sp. (Spirurina: Cystidicolidae) from the gastrointestinal tract of an oarfish, Regalecus russelii, (Regalecidae), captured off the coast of Fukuoka Prefecture, Kyushu Island, Japan is the first nematode described from an oarfish. Diagnostic characters of the new species are: female length of 6.5-8.7 mm, well-developed submedian labia, psuedolabia with pointed apices, excretory pore positioned between spine rows 20 and 22, posterior position of vulva, large oval uterus, long spicule length of 710-1350 μm, wide, flattened, short, right spicule, 12:1 to 16:1 ratio between the length of the long and short spicules and 4 pairs pre-anal and 5 pairs post-anal genital papillae supported by narrow caudal alae. Unusual features such as the bifurcation of the long, left spicule and the short right spicule serving as a gubernaculum are discussed further.
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Introduced marine species are a major environmental and economic problem. The rate of these biological invasions has substantially increased in recent years due to the globalization of the world's economies. The damage caused by... more
Introduced marine species are a major environmental and economic problem. The rate of these biological invasions has substantially increased in recent years due to the globalization of the world's economies. The damage caused by invasive species is often a result of the higher densities and larger sizes they attain compared to where they are native. A prominent hypothesis explaining the success of introduced species is that they are relatively free of the effects of natural enemies. Most notably, they may encounter fewer ...
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Crabs native to Tasmania (Australia) were surveyed with the following aims: to provide background data should a parasite be released for biocontrol purposes on the green crab (Carcinus maenas); to determine natural sources for native... more
Crabs native to Tasmania (Australia) were surveyed with the following aims: to provide background data should a parasite be released for biocontrol purposes on the green crab (Carcinus maenas); to determine natural sources for native parasites involving the green crab as host; to compare the introduced green crab parasitofauna with that of taxonomically and or ecologically similar crabs; to obtain information, through trophic transmission, about possible crab host mortality sources and to discover possible model systems for research ...
A description is given of the community (guild) structure of larval trematodes in Cerithidia californica, with regard to patterns of association of larval trematodes, geographic distribution, temporal and spatial heterogeneity, causes of... more
A description is given of the community (guild) structure of larval trematodes in Cerithidia californica, with regard to patterns of association of larval trematodes, geographic distribution, temporal and spatial heterogeneity, causes of negative interactions, neutral interactions, positive interactions and dominance.
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Many introduced marine organisms are ecological and economic pests. Nevertheless, no management approach is available to mitigate their impacts. Now, a theoretical perspective borrows principles from classical biological control, as... more
Many introduced marine organisms are ecological and economic pests. Nevertheless, no management approach is available to mitigate their impacts. Now, a theoretical perspective borrows principles from classical biological control, as widely applied to terrestrial and fresh water systems, to control the abundance of introduced marine pests. A banner example of a marine pest is the European green crab, Carcinus maenas (L.) (Brachyura: Cancridae). This crab invaded San Francisco Bay in the late 1980s and has expanded its geographic range at a record rate. Studies on the Pacific coast of the U.S.A. and elsewhere strongly indicate that it is a worst-case introduction, affecting native organisms and potentially harming fisheries and aquaculture. Extensive studies show that a significant element of its success, where introduced, has been release from its natural enemies, notably parasites. Natural enemies are infectious agents with potential to contribute to green crab biological control in...
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CSIRO Home Research Publications Repository: ...
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Eliminating human parasitic disease often requires interrupting complex transmission pathways. Even when drugs to treat people are available, disease control can be difficult if the parasite can persist in nonhuman hosts. Here, we show... more
Eliminating human parasitic disease often requires interrupting complex transmission pathways. Even when drugs to treat people are available, disease control can be difficult if the parasite can persist in nonhuman hosts. Here, we show that restoration of a natural predator of a parasite's intermediate hosts may enhance drug-based schistosomiasis control. Our study site was the Senegal River Basin, where villagers suffered a massive outbreak and persistent epidemic after the 1986 completion of the Diama Dam. The dam blocked the annual migration of native river prawns (Macrobrachium vollenhoveni) that are voracious predators of the snail intermediate hosts for schistosomiasis. We tested schistosomiasis control by reintroduced river prawns in a before-after-control-impact field experiment that tracked parasitism in snails and people at two matched villages after prawns were stocked at one village's river access point. The abundance of infected snails was 80% lower at that vill...
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We examined 149 marbled shore crabs, Pachygrapsus marmoratus, from the coast of Portugal for parasites. In particular, we focused our effort on the crab thoracic ganglion. The thoracic ganglion is the largest concentration of nervous... more
We examined 149 marbled shore crabs, Pachygrapsus marmoratus, from the coast of Portugal for parasites. In particular, we focused our effort on the crab thoracic ganglion. The thoracic ganglion is the largest concentration of nervous tissue in a crab and thus, parasites associated with this organ are well situated to influence host behavior. We found metacercariae of two microphallid trematode species in the thoracic ganglion. We also found a microsporan and an apicomplexan associated with the thoracic ganglion. Other parasites not associated with the thoracic ganglion included gregarine trophozoites which were present in the digestive diverticulae in some of the crabs and the entoniscid isopod, Grapsion cavolini. Metacercariae of one of the trematodes (probably Microphallus pachygrapsi (Deblock and Prevot)), may influence the mortality of its host.
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For trophically transmitted parasites that manipulate the phenotype of their hosts, whether the parasites do or do not experience resource competition depends on such factors as the size of the parasites relative to their hosts, the... more
For trophically transmitted parasites that manipulate the phenotype of their hosts, whether the parasites do or do not experience resource competition depends on such factors as the size of the parasites relative to their hosts, the intensity of infection, the extent to which parasites share the cost of defending against the host's immune system or manipulating their host, and the extent to which parasites share transmission goals. Despite theoretical expectations for situations in which either no, or positive, or negative density-dependence should be observed, most studies document only negative density-dependence for trophically transmitted parasites. However, this trend may be an artifact of most studies having focused on systems in which parasites are large relative to their hosts. Yet, systems are common where parasites are small relative to their hosts, and these trophically transmitted parasites may be less likely to experience resource limitation. We looked for signs of ...
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In Lake Fjellfrøsvatn, northern Norway, the larval helminths Cyathocephalus truncatus and Cystidicola farionis use Gammarus lacustris as intermediate hosts and Arctic charr (Salvelinus alpinus) as final hosts. There was sampled 1,433 live... more
In Lake Fjellfrøsvatn, northern Norway, the larval helminths Cyathocephalus truncatus and Cystidicola farionis use Gammarus lacustris as intermediate hosts and Arctic charr (Salvelinus alpinus) as final hosts. There was sampled 1,433 live G. lacustris from the lake and 1,964 G. lacustris from stomach contents of the charr. Prevalence of infection were, respectively, 0.49% and 3.72% for C. truncatus, and 0.21% and 0.20% for C. farionis. Usually, only 1 parasite was present in each host, and the 2 parasite species never co-occurred. Gammarus lacustris amphipods parasitized by C. truncatus were positively selected by the Arctic charr and were consumed approximately 8 times as often as were the unparasitized amphipods or the amphipods infected with C. farionis. This suggests that G. lacustris amphipods infected with C. truncatus larvae are more susceptible to predation than noninfected specimens, probably because of parasite-induced alterations in behavior or visibility. Alternatively, this could also be explained by selection toward the largest G. lacustris specimens observed, which are also the most frequently parasitized amphipods. However, the data show clearly that this was not a result of size-selective predation by the charr. In contrast, the presence of C. farionis did not increase the susceptibility to predation of its intermediate host. The discrepancy between the 2 helminth species supports the hypothesis that parasite-increased susceptibility to predation is related to the life history strategies of the parasites.