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Yamashita J, Sato T, Watanabe K. Hairworm Infection and Seasonal Changes in Paratenic Hosts in a Mountain Stream in Japan. J Parasitol 2017; 103:32-37. [DOI: 10.1645/15-887] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Affiliation(s)
- J. Yamashita
- Laboratory of Animal Ecology, Division of Zoology, Department of Biological Sciences, Graduate School of Sciences, Kyoto University, Kitashirakawa-Oiwake-cho, Sakyo-ku, Kyoto 606-8502, Japan
| | - T. Sato
- Laboratory of Animal Ecology, Division of Zoology, Department of Biological Sciences, Graduate School of Sciences, Kyoto University, Kitashirakawa-Oiwake-cho, Sakyo-ku, Kyoto 606-8502, Japan
| | - K. Watanabe
- Laboratory of Animal Ecology, Division of Zoology, Department of Biological Sciences, Graduate School of Sciences, Kyoto University, Kitashirakawa-Oiwake-cho, Sakyo-ku, Kyoto 606-8502, Japan
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Cizauskas CA, Carlson CJ, Burgio KR, Clements CF, Dougherty ER, Harris NC, Phillips AJ. Parasite vulnerability to climate change: an evidence-based functional trait approach. ROYAL SOCIETY OPEN SCIENCE 2017; 4:160535. [PMID: 28280551 PMCID: PMC5319317 DOI: 10.1098/rsos.160535] [Citation(s) in RCA: 46] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/22/2016] [Accepted: 12/06/2016] [Indexed: 05/19/2023]
Abstract
Despite the number of virulent pathogens that are projected to benefit from global change and to spread in the next century, we suggest that a combination of coextinction risk and climate sensitivity could make parasites at least as extinction prone as any other trophic group. However, the existing interdisciplinary toolbox for identifying species threatened by climate change is inadequate or inappropriate when considering parasites as conservation targets. A functional trait approach can be used to connect parasites' ecological role to their risk of disappearance, but this is complicated by the taxonomic and functional diversity of many parasite clades. Here, we propose biological traits that may render parasite species particularly vulnerable to extinction (including high host specificity, complex life cycles and narrow climatic tolerance), and identify critical gaps in our knowledge of parasite biology and ecology. By doing so, we provide criteria to identify vulnerable parasite species and triage parasite conservation efforts.
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Affiliation(s)
- Carrie A. Cizauskas
- Department of Environmental Science, Policy, and Management, University of California, Berkeley, CA, USA
- Author for correspondence: Carrie A. Cizauskas e-mail:
| | - Colin J. Carlson
- Department of Environmental Science, Policy, and Management, University of California, Berkeley, CA, USA
| | - Kevin R. Burgio
- Department of Ecology and Evolutionary Biology, University of Connecticut, Storrs, CT, USA
| | - Chris F. Clements
- Institute of Evolutionary Biology and Environmental Studies, The University of Zurich, Zurich, Switzerland
| | - Eric R. Dougherty
- Department of Environmental Science, Policy, and Management, University of California, Berkeley, CA, USA
| | - Nyeema C. Harris
- Department of Ecology and Evolutionary Biology, University of Michigan, Ann Arbor, MI, USA
| | - Anna J. Phillips
- Department of Invertebrate Zoology, Smithsonian's National Museum of Natural History, Washington, DC, USA
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Kamenova S, Bartley T, Bohan D, Boutain J, Colautti R, Domaizon I, Fontaine C, Lemainque A, Le Viol I, Mollot G, Perga ME, Ravigné V, Massol F. Invasions Toolkit. ADV ECOL RES 2017. [DOI: 10.1016/bs.aecr.2016.10.009] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
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Dougherty ER, Carlson CJ, Bueno VM, Burgio KR, Cizauskas CA, Clements CF, Seidel DP, Harris NC. Paradigms for parasite conservation. CONSERVATION BIOLOGY : THE JOURNAL OF THE SOCIETY FOR CONSERVATION BIOLOGY 2016; 30:724-33. [PMID: 26400623 DOI: 10.1111/cobi.12634] [Citation(s) in RCA: 53] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/25/2015] [Revised: 09/11/2015] [Accepted: 09/18/2015] [Indexed: 05/03/2023]
Abstract
Parasitic species, which depend directly on host species for their survival, represent a major regulatory force in ecosystems and a significant component of Earth's biodiversity. Yet the negative impacts of parasites observed at the host level have motivated a conservation paradigm of eradication, moving us farther from attainment of taxonomically unbiased conservation goals. Despite a growing body of literature highlighting the importance of parasite-inclusive conservation, most parasite species remain understudied, underfunded, and underappreciated. We argue the protection of parasitic biodiversity requires a paradigm shift in the perception and valuation of their role as consumer species, similar to that of apex predators in the mid-20th century. Beyond recognizing parasites as vital trophic regulators, existing tools available to conservation practitioners should explicitly account for the unique threats facing dependent species. We built upon concepts from epidemiology and economics (e.g., host-density threshold and cost-benefit analysis) to devise novel metrics of margin of error and minimum investment for parasite conservation. We define margin of error as the risk of accidental host extinction from misestimating equilibrium population sizes and predicted oscillations, while minimum investment represents the cost associated with conserving the additional hosts required to maintain viable parasite populations. This framework will aid in the identification of readily conserved parasites that present minimal health risks. To establish parasite conservation, we propose an extension of population viability analysis for host-parasite assemblages to assess extinction risk. In the direst cases, ex situ breeding programs for parasites should be evaluated to maximize success without undermining host protection. Though parasitic species pose a considerable conservation challenge, adaptations to conservation tools will help protect parasite biodiversity in the face of an uncertain environmental future.
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Affiliation(s)
- Eric R Dougherty
- Department of Environmental Science, Policy, and Management, University of California, Berkeley, 130 Mulford Hall, Berkeley, CA, 94720, U.S.A
| | - Colin J Carlson
- Department of Environmental Science, Policy, and Management, University of California, Berkeley, 130 Mulford Hall, Berkeley, CA, 94720, U.S.A
| | - Veronica M Bueno
- Department of Ecology and Evolutionary Biology, University of Connecticut, 75 N. Eagleville Road, Storrs, CT, 06269, U.S.A
| | - Kevin R Burgio
- Department of Ecology and Evolutionary Biology, University of Connecticut, 75 N. Eagleville Road, Storrs, CT, 06269, U.S.A
| | - Carrie A Cizauskas
- Department of Ecology and Evolutionary Biology, Princeton University, 106A Guyot Hall, Princeton, NJ, 08544, U.S.A
| | - Christopher F Clements
- Institute of Evolutionary Biology and Environmental Studies, University of Zurich, Winterthurerstrasse 190, CH-8057, Zurich, Switzerland
| | - Dana P Seidel
- Department of Environmental Science, Policy, and Management, University of California, Berkeley, 130 Mulford Hall, Berkeley, CA, 94720, U.S.A
| | - Nyeema C Harris
- Ecology and Evolutionary Biology, University of Michigan, 830 North University Avenue, Ann Arbor, MI, 48109, U.S.A
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Ernst CM, Hanelt B, Buddle CM. Parasitism of Ground Beetles (Coleoptera: Carabidae) by a New Species of Hairworm (Nematomorpha: Gordiida) in Arctic Canada. J Parasitol 2016; 102:327-35. [DOI: 10.1645/15-863] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
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Sato T, El-Sabaawi RW, Campbell K, Ohta T, Richardson JS. A test of the effects of timing of a pulsed resource subsidy on stream ecosystems. J Anim Ecol 2016; 85:1136-46. [PMID: 26972564 DOI: 10.1111/1365-2656.12516] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2015] [Accepted: 02/17/2016] [Indexed: 11/28/2022]
Abstract
Spatial resource subsidies can alter bottom-up and top-down forces of community regulation across ecosystem boundaries. Most subsidies are temporally variable, and recent theory has suggested that consumer-resource dynamics can be stabilized if the peak timing of a subsidy is desynchronized with that of prey productivity in the recipient ecosystem. However, magnitude of consumer responses per se could depend on the subsidy timing, which may be a critical component for community dynamics and ecosystem processes. The aim of this study was to test (i) whether a recipient consumer (cutthroat trout) responds differently to a resource subsidy occurring early in its growing season than to a subsidy occurring late in the season and, if this is the case, (ii) whether the timing-dependent consumer response has cascading effects on communities and ecosystem functions in streams. To test those hypotheses, we conducted a large-scale field experiment, in which we directly manipulated the timing of augmentation of the terrestrial invertebrates that enter stream (i.e. peak timing of June-August vs. August-October), keeping constant the total amounts of the invertebrates entered. We found large increases in the individual growth rate and population biomass of the cutthroat trout, in response to the early resource pulse, but not to the late pulse. This timing-dependent consumer response cascaded down to reduce benthic invertebrates and leaf breakdown rate, and increased water nutrient concentrations. Furthermore, the early resource pulse resulted in higher maturity rate of the cutthroat trout in the following spring, demonstrating the importance of the subsidy timing on long-term community dynamics via the consumer's numerical response. Our results emphasize the need to acknowledge timing-dependent consumer responses in understanding the effects of subsidies on communities and ecosystem processes. Elucidating the mechanisms by which consumers effectively exploit pulsed subsidies is an important avenue to better understand community dynamics in spatially coupled ecosystems.
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Affiliation(s)
- Takuya Sato
- The Hakubi Center for Advanced Research, Kyoto University, Yoshida-honmachi, Sakyo-ku, Kyoto, 606-8501, Japan
| | - Rana W El-Sabaawi
- Department of Biology, University of Victoria, Victoria, BC, V8W 3N5, Canada
| | - Kirsten Campbell
- Department of Forest & Conservation Sciences, University of British Columbia, Forest Sciences Centre 3041, 2424 Main Mall, Vancouver, BC, V6T 1Z4, Canada
| | - Tamihisa Ohta
- Tomakomai Research Station, Field Science Center for Northern Biosphere, Hokkaido University, Takaoka, Tomakomai, Hokkaido, 053-0035, Japan
| | - John S Richardson
- Department of Forest & Conservation Sciences, University of British Columbia, Forest Sciences Centre 3041, 2424 Main Mall, Vancouver, BC, V6T 1Z4, Canada
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58
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Chiu MC, Huang CG, Wu WJ, Shiao SF. Annual Survey of Horsehair Worm Cysts in Northern Taiwan, with Notes on a Single Seasonal Infection Peak in Chironomid Larvae (Diptera: Chironomidae). J Parasitol 2016; 102:319-26. [PMID: 26885875 DOI: 10.1645/15-907] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Abstract
The life cycle of the freshwater horsehair worm typically includes a free-living phase (adult, egg, larva) and a multiple-host parasitic phase (aquatic paratenic host, terrestrial definitive host). Such a life cycle involving water and land can improve energy flow in riparian ecosystems; however, its temporal dynamics in nature have rarely been investigated. This study examined seasonal infection with cysts in larval Chironominae (Diptera: Chironomidae) in northern Taiwan. In the larval chironomids, cysts of 3 horsehair worm species were identified. The cysts of the dominant species were morphologically similar to those of Chordodes formosanus. Infection with these cysts increased suddenly and peaked 2 mo after the reproductive season of the adult horsehair worms. Although adult C. formosanus emerged several times in a year, only 1 distinct infection peak was detected in September in the chironomid larvae. Compared with the subfamily Chironominae, samples from the subfamilies Tanypodinae and Orthocladiinae were less parasitized. This indicates that the feeding behavior of the chironomid host likely affects horsehair worm cyst infections; however, bioconcentration in predatory chironomids was not detected.
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Affiliation(s)
- Ming-Chung Chiu
- Department of Entomology, National Taiwan University, Taipei 106, Taiwan
| | - Chin-Gi Huang
- Department of Entomology, National Taiwan University, Taipei 106, Taiwan
| | - Wen-Jer Wu
- Department of Entomology, National Taiwan University, Taipei 106, Taiwan
| | - Shiuh-Feng Shiao
- Department of Entomology, National Taiwan University, Taipei 106, Taiwan
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59
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Wood CL, Johnson PT. A world without parasites: exploring the hidden ecology of infection. FRONTIERS IN ECOLOGY AND THE ENVIRONMENT 2015; 13:425-434. [PMID: 28077932 PMCID: PMC5222570 DOI: 10.1890/140368] [Citation(s) in RCA: 86] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
Parasites have historically been considered a scourge, deserving of annihilation. Although parasite eradications rank among humanity's greatest achievements, new research is shedding light on the collateral effects of parasite loss. Here, we explore a "world without parasites": a thought experiment for illuminating the ecological roles that parasites play in ecosystems. While there is robust evidence for the effects of parasites on host individuals (eg affecting host vital rates), this exercise highlights how little we know about the influence of parasites on communities and ecosystems (eg altering energy flow through food webs). We present hypotheses for novel, interesting, and general effects of parasites. These hypotheses are largely untested, and should be considered a springboard for future research. While many uncertainties exist, the available evidence suggests that a world without parasites would be very different from the world we know, with effects extending from host individuals to populations, communities, and even ecosystems.
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Affiliation(s)
- Chelsea L Wood
- Department of Ecology and Evolutionary Biology, University of Michigan, Ann Arbor, MI; Michigan Society of Fellows, University of Michigan, Ann Arbor, MI; Department of Ecology and Evolutionary Biology, University of Colorado, Boulder, CO
| | - Pieter Tj Johnson
- Department of Ecology and Evolutionary Biology, University of Colorado, Boulder, CO
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60
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Host manipulation in the face of environmental changes: Ecological consequences. INTERNATIONAL JOURNAL FOR PARASITOLOGY-PARASITES AND WILDLIFE 2015; 4:442-51. [PMID: 26835252 PMCID: PMC4699980 DOI: 10.1016/j.ijppaw.2015.08.001] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/29/2015] [Revised: 07/30/2015] [Accepted: 08/03/2015] [Indexed: 12/27/2022]
Abstract
Several parasite species, particularly those having complex life-cycles, are known to induce phenotypic alterations in their hosts. Most often, such alterations appear to increase the fitness of the parasites at the expense of that of their hosts, a phenomenon known as “host manipulation”. Host manipulation can have important consequences, ranging from host population dynamics to ecosystem engineering. So far, the importance of environmental changes for host manipulation has received little attention. However, because manipulative parasites are embedded in complex systems, with many interacting components, changes in the environment are likely to affect those systems in various ways. Here, after reviewing the ecological importance of manipulative parasites, we consider potential causes and consequences of changes in host manipulation by parasites driven by environmental modifications. We show that such consequences can extend to trophic networks and population dynamics within communities, and alter the ecological role of manipulative parasites such as their ecosystem engineering. We suggest that taking them into account could improve the accuracy of predictions regarding the effects of global change. We also propose several directions for future studies. Environmental changes can affect ecosystems in various ways. Manipulative parasites are known to play numerous roles within ecosystems. However, the effects of environmental changes on manipulation has been overlooked. We review those effects and their potential consequences on larger scales. We conclude with suggestions on the direction of future studies.
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61
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Gopko M, Mikheev VN, Taskinen J. Changes in host behaviour caused by immature larvae of the eye fluke: evidence supporting the predation suppression hypothesis. Behav Ecol Sociobiol 2015. [DOI: 10.1007/s00265-015-1984-z] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Takasuka K, Yasui T, Ishigami T, Nakata K, Matsumoto R, Ikeda K, Maeto K. Host manipulation by an ichneumonid spider ectoparasitoid that takes advantage of preprogrammed web-building behaviour for its cocoon protection. J Exp Biol 2015; 218:2326-32. [DOI: 10.1242/jeb.122739] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
ABSTRACT
Host manipulation by parasites and parasitoids is a fascinating phenomenon within evolutionary ecology, representing an example of extended phenotypes. To elucidate the mechanism of host manipulation, revealing the origin and function of the invoked actions is essential. Our study focused on the ichneumonid spider ectoparasitoid Reclinervellus nielseni, which turns its host spider (Cyclosa argenteoalba) into a drugged navvy, to modify the web structure into a more persistent cocoon web so that the wasp can pupate safely on this web after the spider's death. We focused on whether the cocoon web originated from the resting web that an unparasitized spider builds before moulting, by comparing web structures, building behaviour and silk spectral/tensile properties. We found that both resting and cocoon webs have reduced numbers of radii decorated by numerous fibrous threads and specific decorating behaviour was identical, suggesting that the cocoon web in this system has roots in the innate resting web and ecdysteroid-related components may be responsible for the manipulation. We also show that these decorations reflect UV light, possibly to prevent damage by flying web-destroyers such as birds or large insects. Furthermore, the tensile test revealed that the spider is induced to repeat certain behavioural steps in addition to resting web construction so that many more threads are laid down for web reinforcement.
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Affiliation(s)
- Keizo Takasuka
- Laboratory of Insect Biodiversity and Ecosystem Science, Graduate School of Agricultural Science, Kobe University, Hyogo 657-8501, Japan
| | - Tomoki Yasui
- Department of Chemical Science and Engineering, Graduate School of Engineering, Kobe University, Hyogo 657-8501, Japan
| | - Toru Ishigami
- Department of Chemical Science and Engineering, Graduate School of Engineering, Kobe University, Hyogo 657-8501, Japan
| | - Kensuke Nakata
- Faculty for the Study of Contemporary Society, Kyoto Women's University, Kyoto 605-8501, Japan
| | | | - Kenichi Ikeda
- Laboratory of Stress Cytology, Graduate School of Agricultural Science, Kobe University, Hyogo 657-8501, Japan
| | - Kaoru Maeto
- Laboratory of Insect Biodiversity and Ecosystem Science, Graduate School of Agricultural Science, Kobe University, Hyogo 657-8501, Japan
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Labaude S, Cézilly F, Tercier X, Rigaud T. Influence of host nutritional condition on post-infection traits in the association between the manipulative acanthocephalan Pomphorhynchus laevis and the amphipod Gammarus pulex. Parasit Vectors 2015. [PMID: 26223476 PMCID: PMC4520090 DOI: 10.1186/s13071-015-1017-9] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Several parasites with complex life-cycles induce phenotypic alterations in their intermediate hosts. According to the host manipulation hypothesis, such phenotypic alterations are supposed to increase the fitness of the parasite at the expense of that of its intermediate hosts through increasing the probability of transmission to next hosts. Although the phenomenon has received a large attention, the proximate factors modulating the occurrence and intensity of host manipulation remain poorly known. It has however, been suggested that the amount of energy reserves in the intermediate host might be a key parameter, although its precise influence on the intensity of manipulation remains unclear. Dietary depletion in the host may also lead to compromise with other parasite traits, such as probability of establishing or growth or virulence. METHODS Here, we address the question through performing experimental infections of the freshwater amphipod Gammarus pulex with two different populations of the acanthocephalan fish parasite Pomphorhynchus laevis, and manipulation of host nutritional condition. Following exposure, gammarids were given either a "standard" diet (consisting of elm leaves and chironomid larvae) or a "deprived" food treatment (deprived in proteins), and infection parameters were recorded. Once parasites reached the stage at which they become infective to their definitive host, refuge use (a behavioural trait presumably implied in trophic transmission) was assessed, and metabolic rate was measured. RESULTS Infected gammarids exposed to the deprived food treatment showed a lower metabolic rate, indicative of a lower body condition, compared to those exposed to the standard food treatment. Parasite size was smaller, and, depending on the population of origin of the parasites, intensity of infection was lower or mortality was higher in deprived hosts. However, food treatment had no effect on either the timing or intensity of behavioural modifications. CONCLUSIONS Overall, while our results suggest that acanthocephalan parasites develop better in hosts in good condition, no evidence was found for an influence of host nutritional condition on host manipulation by parasites.
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Affiliation(s)
- Sophie Labaude
- Université de Bourgogne Franche-Comté, UMR CNRS 6282 Biogéosciences, Dijon, France.
| | - Frank Cézilly
- Université de Bourgogne Franche-Comté, UMR CNRS 6282 Biogéosciences, Dijon, France.
| | - Xavier Tercier
- Université de Bourgogne Franche-Comté, UMR CNRS 6282 Biogéosciences, Dijon, France.
| | - Thierry Rigaud
- Université de Bourgogne Franche-Comté, UMR CNRS 6282 Biogéosciences, Dijon, France.
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Kadoya EZ, Ishii HS. Host manipulation of bumble bee queens bySphaerularianematodes indirectly affects foraging of non-host workers. Ecology 2015; 96:1361-70. [DOI: 10.1890/14-0036.1] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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65
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Bao G, Suetsugu K, Wang H, Yao X, Liu L, Ou J, Li C. Effects of the hemiparasitic plant Pedicularis kansuensis on plant community structure in a degraded grassland. Ecol Res 2015. [DOI: 10.1007/s11284-015-1248-4] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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66
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Han Y, van Oers MM, van Houte S, Ros VID. Virus-Induced Behavioural Changes in Insects. HOST MANIPULATIONS BY PARASITES AND VIRUSES 2015. [DOI: 10.1007/978-3-319-22936-2_10] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/03/2022]
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67
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Wood CL, Sandin SA, Zgliczynski B, Guerra AS, Micheli F. Fishing drives declines in fish parasite diversity and has variable effects on parasite abundance. Ecology 2014; 95:1929-46. [PMID: 25163125 DOI: 10.1890/13-1270.1] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Despite the ubiquity and ecological importance of parasites, relatively few studies have assessed their response to anthropogenic environmental change. Heuristic models have predicted both increases and decreases in parasite abundance in response to human disturbance, with empirical support for both. However, most studies focus on one or a few selected parasite species. Here, we assess the abundance of parasites of seven species of coral reef fishes collected from three fished and three unfished islands of the Line Islands archipelago in the central equatorial Pacific. Because we chose fish hosts that spanned different trophic levels, taxonomic groups, and body sizes, we were able to compare parasite responses across a broad cross section of the total parasite community in the presence and absence of fishing, a major human impact on marine ecosystems. We found that overall parasite species richness was substantially depressed on fished islands, but that the response of parasite abundance varied among parasite taxa: directly transmitted parasites were significantly more abundant on fished than on unfished islands, while the reverse was true for trophically transmitted parasites. This probably arises because trophically transmitted parasites require multiple host species, some of which are the top predators most sensitive to fishing impacts. The increase in directly transmitted parasites appeared to be due to fishing-driven compensatory increases in the abundance of their hosts. Together, these results provide support for the predictions of both heuristic models, and indicate that the direction of fishing's impact on parasite abundance is mediated by parasite traits, notably parasite transmission strategies.
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68
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Rasconi S, Grami B, Niquil N, Jobard M, Sime-Ngando T. Parasitic chytrids sustain zooplankton growth during inedible algal bloom. Front Microbiol 2014; 5:229. [PMID: 24904543 PMCID: PMC4033230 DOI: 10.3389/fmicb.2014.00229] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2014] [Accepted: 04/29/2014] [Indexed: 11/13/2022] Open
Abstract
This study assesses the quantitative impact of parasitic chytrids on the planktonic food web of two contrasting freshwater lakes during different algal bloom situations. Carbon-based food web models were used to investigate the effects of chytrids during the spring diatom bloom in Lake Pavin (oligo-mesotrophic) and the autumn cyanobacteria bloom in Lake Aydat (eutrophic). Linear inverse modeling was employed to estimate undetermined flows in both lakes. The Monte Carlo Markov chain linear inverse modeling procedure provided estimates of the ranges of model-derived fluxes. Model results confirm recent theories on the impact of parasites on food web function through grazers and recyclers. During blooms of "inedible" algae (unexploited by planktonic herbivores), the epidemic growth of chytrids channeled 19-20% of the primary production in both lakes through the production of grazer exploitable zoospores. The parasitic throughput represented 50% and 57% of the zooplankton diet, respectively, in the oligo-mesotrophic and in the eutrophic lakes. Parasites also affected ecological network properties such as longer carbon path lengths and loop strength, and contributed to increase the stability of the aquatic food web, notably in the oligo-mesotrophic Lake Pavin.
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Affiliation(s)
- Serena Rasconi
- CNRS UMR 6250, UMRi 7266, LIENSs, Université de La Rochelle La Rochelle, France
| | - Boutheina Grami
- CNRS UMR 6250, UMRi 7266, LIENSs, Université de La Rochelle La Rochelle, France
| | - Nathalie Niquil
- CNRS UMR 6250, UMRi 7266, LIENSs, Université de La Rochelle La Rochelle, France
| | - Marlène Jobard
- CNRS UMR 6023, LMGE, Clermont Université Aubière Cedex, France
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69
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Stafford-Banks CA, Yang LH, McMunn MS, Ullman DE. Virus infection alters the predatory behavior of an omnivorous vector. OIKOS 2014. [DOI: 10.1111/oik.01148] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
| | - Louie H. Yang
- Dept of Entomology and Nematology; Univ. of California; Davis Davis CA 95616 USA
| | - Marshall S. McMunn
- Dept of Entomology and Nematology; Univ. of California; Davis Davis CA 95616 USA
| | - Diane E. Ullman
- Dept of Entomology and Nematology; Univ. of California; Davis Davis CA 95616 USA
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Abstract
To understand how fisheries affect parasites, we conducted a meta-analysis of studies that contrasted parasite assemblages in fished and unfished areas. Parasite diversity was lower in hosts from fished areas. Larger hosts had a greater abundance of parasites, suggesting that fishing might reduce the abundance of parasites by selectively removing the largest, most heavily parasitized individuals. After controlling for size, the effect of fishing on parasite abundance varied according to whether the host was fished and the parasite's life cycle. Parasites of unfished hosts were more likely to increase in abundance in response to fishing than were parasites of fished hosts, possibly due to compensatory increases in the abundance of unfished hosts. While complex life cycle parasites tended to decline in abundance in response to fishing, directly transmitted parasites tended to increase. Among complex life cycle parasites, those with fished hosts tended to decline in abundance in response to fishing, while those with unfished hosts tended to increase. However, among directly transmitted parasites, responses did not differ between parasites with and without fished hosts. This work suggests that parasite assemblages are likely to change substantially in composition in increasingly fished ecosystems, and that parasite life history and fishing status of the host are important in predicting the response of individual parasite species or groups to fishing.
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71
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Sato T, Watanabe K. Do stage-specific functional responses of consumers dampen the effects of subsidies on trophic cascades in streams? J Anim Ecol 2014; 83:907-15. [PMID: 24308701 DOI: 10.1111/1365-2656.12192] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2013] [Accepted: 11/28/2013] [Indexed: 10/25/2022]
Affiliation(s)
- Takuya Sato
- The Hakubi Center for Advanced Research; Kyoto University; Yoshida-Ushinomiya-cho Sakyo-ku Kyoto 606-8302 Japan
| | - Katsutoshi Watanabe
- Department of Zoology; Division of Biological Science; Graduate School of Science; Kyoto University; Kitashirakawa-Oiwakecho Sakyo-ku Kyoto 606-8502 Japan
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72
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Preston DL, Orlofske SA, Lambden JP, Johnson PTJ. Biomass and productivity of trematode parasites in pond ecosystems. J Anim Ecol 2013; 82:509-17. [PMID: 23488451 DOI: 10.1111/1365-2656.12030] [Citation(s) in RCA: 70] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2012] [Accepted: 10/29/2012] [Indexed: 11/30/2022]
Abstract
1. Ecologists often measure the biomass and productivity of organisms to understand the importance of populations and communities in the flow of energy through ecosystems. Despite the central role of such studies in the advancement of freshwater ecology, there has been little effort to incorporate parasites into studies of freshwater energy flow. This omission is particularly important considering the roles that parasites sometimes play in shaping community structure and ecosystem processes. 2. Using quantitative surveys and dissections of over 1600 aquatic invertebrate and amphibian hosts, we calculated the ecosystem-level biomass and productivity of trematode parasites alongside the biomass of free-living aquatic organisms in three freshwater ponds in California, USA. 3. Snails and amphibian larvae, which are both important intermediate trematode hosts, dominated the dry biomass of free-living organisms across ponds (snails = 3.2 g m(-2); amphibians = 3.1 g m(-2)). An average of 33.5% of mature snails were infected with one of six trematode taxa, amounting to a density of 13 infected snails m(-2) of pond substrate. Between 18% and 33% of the combined host and parasite biomass within each infected snail consisted of larval trematode tissue, which collectively accounted for 87% of the total trematode biomass within the three ponds. Mid-summer trematode dry biomass averaged 0.10 g m(-2), which was equal to or greater than that of the most abundant insect orders (coleoptera = 0.10 g m(-2), odonata = 0.08 g m(-2), hemiptera = 0.07 g m(-2) and ephemeroptera = 0.03 g m(-2)). 4. On average, each trematode taxon produced between 14 and 1660 free-swimming larvae (cercariae) infected snail(-1) 24 h(-1) in mid-summer. Given that infected snails release cercariae for 3-4 months a year, the pond trematode communities produced an average of 153 mg m(-2) yr(-1) of dry cercarial biomass (range = 70-220 mg m(-2) yr(-1)). 5. Our results suggest that a significant amount of energy moves through trematode parasites in freshwater pond ecosystems, and that their contributions to ecosystem energetics may exceed those of many free-living taxa known to play key roles in structuring aquatic communities.
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Affiliation(s)
- Daniel L Preston
- Department of Ecology and Evolutionary Biology, University of Colorado, Ramaley N122, Campus Box 334, Boulder, Colorado, 80309, USA
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73
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Bolek MG, Rogers E, Szmygiel C, Shannon RP, Doerfert-Schrader WE, Schmidt-Rhaesa A, Hanelt B. Survival of larval and cyst stages of gordiids (Nematomorpha) after exposure to freezing. J Parasitol 2012; 99:397-402. [PMID: 23252693 DOI: 10.1645/12-62.1] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Abstract
Hairworms infect terrestrial arthropods and are 1 of the most understudied groups of parasites. Recently, life cycles of 2 gordiids (Paragordius varius and Paragordius obamai) have been domesticated in the laboratory. We tested the viability of laboratory reared and post-frozen larval and cyst stages of the North American gordiid, P. varius , frozen at -80 C for 7 mo, and the viability of field collected and post-frozen cysts of the African (P. obamai) and North American ( P. varius ) gordiid frozen at -20 C for 2 mo. All snails exposed to post-frozen or control P. varius larvae became infected with cysts, and there was no significant difference in prevalence or mean intensity of cysts among control or experimental snail groups. As with larvae, no significant differences were observed in prevalence or mean intensity of emerging worms from crickets infected with post-frozen or control P. obamai or P. varius cysts. All female P. obamai and P. varius worms from control and post-frozen cyst infections laid eggs and larvae hatched from some of these eggs. Survival and cyst formation of P. varius larvae exposed to different combinations of drying and/or freezing temperatures indicated that gordiid larvae have the ability to survive drying and freezing, but survival significantly increases during freezing at lower temperatures. The major contribution of our study is the demonstration that gordiid larval and cyst stages can survive freezing temperatures to infect and develop in the next host.
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Affiliation(s)
- Matthew G Bolek
- Department of Zoology, Oklahoma State University, Stillwater, Oklahoma 74078, USA
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74
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Sato T, Watanabe K, Tamotsu S, Ichikawa A, Schmidt-Rhaesa A. Diversity of nematomorph and cohabiting nematode parasites in riparian ecosystems around the Kii Peninsula, Japan. CAN J ZOOL 2012. [DOI: 10.1139/z2012-048] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Nematomorph parasites manipulate terrestrial invertebrate hosts to seek out and enter streams, thereby deriving substantial energy subsidies to stream salmonids. Despite this potential ecological role of nematomorphs, knowledge of their diversity remains unclear. Using molecular (i.e., 18S rRNA and mitochondrial COI genes) and morphological approaches, we explored the species diversity of suspected nematomorph specimens, as well as their terrestrial orthopteran hosts, in 10 stream and riparian ecosystems around the Kii Peninsula, central Honshu, Japan. We distinguished seven species of nematomorphs belonging to three genera based on molecular and morphological data. The identifications by the two approaches were consistent with each other at the genus level but partly not at the species level. Furthermore, among the suspected nematomorph specimens, eight nematode species belonging to the orders Mermithida and Trichocephalida were found from two sites. Several orthopterans, mainly camel crickets, were infected by nematomorphs and by a nematode without obvious species specificity. These results suggest that diverse parasites and their orthopteran hosts drive the parasite-mediated energy flow across the stream and riparian ecosystems.
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Affiliation(s)
- Takuya Sato
- The Hakubi Center for Advanced Research, Kyoto University, Yoshida-Ushinomiya-cyou, Sakyo-ku, Kyoto 606-8302, Japan
| | - Katsutoshi Watanabe
- Department of Zoology, Division of Biological Science, Graduate School of Science, Kyoto University, Kitashirakawa-Oiwakecho, Sakyo-ku, Kyoto 606-8502, Japan
| | - Satoshi Tamotsu
- Department of Biological Sciences, Nara Women’s University, Kitauoya-Nishi machi, Nara 630-8506 Japan
| | - Akihiko Ichikawa
- Orthopterological Society of Japan, 310 Kitadai Building, 17-13 Hirao-4 chome, Taisho-ku, Osaka 551-0012, Japan
| | - Andreas Schmidt-Rhaesa
- Zoological Museum, University Hamburg, Martin-Luther-King-Platz 3, 20146, Hamburg, Germany
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75
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Effects of an invasive plant transcend ecosystem boundaries through a dragonfly-mediated trophic pathway. Oecologia 2012; 170:1045-52. [PMID: 22622872 PMCID: PMC3496476 DOI: 10.1007/s00442-012-2357-1] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2011] [Accepted: 05/01/2012] [Indexed: 10/28/2022]
Abstract
Trophic interactions can strongly influence the structure and function of terrestrial and aquatic communities through top-down and bottom-up processes. Species with life stages in both terrestrial and aquatic systems may be particularly likely to link the effects of trophic interactions across ecosystem boundaries. Using experimental wetlands planted with purple loosestrife (Lythrum salicaria), we tested the degree to which the bottom-up effects of floral density of this invasive plant could trigger a chain of interactions, changing the behavior of terrestrial flying insect prey and predators and ultimately cascading through top-down interactions to alter lower trophic levels in the aquatic community. The results of our experiment support the linkage of terrestrial and aquatic food webs through this hypothesized pathway, with high loosestrife floral density treatments attracting high levels of visiting insect pollinators and predatory adult dragonflies. High floral densities were also associated with increased adult dragonfly oviposition and subsequently high larval dragonfly abundance in the aquatic community. Finally, high-flower treatments were coupled with changes in zooplankton species richness and shifts in the composition of zooplankton communities. Through changes in animal behavior and trophic interactions in terrestrial and aquatic systems, this work illustrates the broad and potentially cryptic effects of invasive species, and provides additional compelling motivation for ecologists to conduct investigations that cross traditional ecosystem boundaries.
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76
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Sato T, Egusa T, Fukushima K, Oda T, Ohte N, Tokuchi N, Watanabe K, Kanaiwa M, Murakami I, Lafferty KD. Nematomorph parasites indirectly alter the food web and ecosystem function of streams through behavioural manipulation of their cricket hosts. Ecol Lett 2012; 15:786-93. [DOI: 10.1111/j.1461-0248.2012.01798.x] [Citation(s) in RCA: 78] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2012] [Revised: 02/03/2012] [Accepted: 04/16/2012] [Indexed: 10/28/2022]
Affiliation(s)
- Takuya Sato
- The Hakubi Center for Advanced Research; Kyoto University; Yoshida-Ushinomiya-cyou; Sakyo-ku; Kyoto; 606-8302; Japan
| | - Tomohiro Egusa
- Department of Forest Science; Graduate School of Agricultural and Life Sciences; The University of Tokyo; 1-1-1 Yayoi; Bunkyo-ku; Tokyo; 113-8657; Japan
| | - Keitaro Fukushima
- Field Science Education and Research Center; Kyoto University; Kitashirakawa-Oiwakecho; Sakyo-ku; Kyoto; 606-8502; Japan
| | - Tomoki Oda
- Department of Forest Science; Graduate School of Agricultural and Life Sciences; The University of Tokyo; 1-1-1 Yayoi; Bunkyo-ku; Tokyo; 113-8657; Japan
| | - Nobuhito Ohte
- Department of Forest Science; Graduate School of Agricultural and Life Sciences; The University of Tokyo; 1-1-1 Yayoi; Bunkyo-ku; Tokyo; 113-8657; Japan
| | - Naoko Tokuchi
- Field Science Education and Research Center; Kyoto University; Kitashirakawa-Oiwakecho; Sakyo-ku; Kyoto; 606-8502; Japan
| | - Katsutoshi Watanabe
- Department of Zoology; Division of Biological Science; Graduate School of Science; Kyoto University; Kitashirakawa-Oiwakecho; Sakyo-ku; Kyoto; 606-8502; Japan
| | - Minoru Kanaiwa
- Faculty of Bio-Industry; Tokyo University of Agriculture; 196 Yasaka; Abashiri-city; Hokkaido; 099-2493; Japan
| | - Isaya Murakami
- Regional Environmental Planning Inc.; Midori Akutagawa Building; 1-15-18; Akutagawacho; Takatsuki-city; Osaka; 569-1123; Japan
| | - Kevin D. Lafferty
- U.S. Geological Survey; Western Ecological Research Center; c/o Marine Science Institute; University of California; Santa Barbara
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77
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Sato T, Watanabe K, Tokuchi N, Kamauchi H, Harada Y, Lafferty KD. A nematomorph parasite explains variation in terrestrial subsidies to trout streams in Japan. OIKOS 2011. [DOI: 10.1111/j.1600-0706.2011.19121.x] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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78
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Holt RD. IJEE Soapbox: World free of parasites and vectors: Would it be heaven, or would it be hell? Isr J Ecol Evol 2010. [DOI: 10.1560/ijee.56.3-4.239] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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