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Jakovlić I, Ye T, Zou H, Zhu F, Shi Y, Ma Y, Wang GT, Li WX, Zhang D. Drivers of interlineage variability in mitogenomic evolutionary rates in Platyhelminthes. Heredity (Edinb) 2024; 133:276-286. [PMID: 39095653 PMCID: PMC11436680 DOI: 10.1038/s41437-024-00712-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2024] [Revised: 07/25/2024] [Accepted: 07/26/2024] [Indexed: 08/04/2024] Open
Abstract
Studies of forces driving interlineage variability in the evolutionary rates (both sequence and architecture) of mitochondrial genomes often produce contradictory results. Flatworms (Platyhelminthes) exhibit the fastest-evolving mitogenomic sequences among all bilaterian phyla. To test the effects of multiple factors previously associated with different aspects of mitogenomic evolution, we used mitogenomes of 223 flatworm species, phylogenetic multilevel regression models, and causal inference. Thermic host environment (endothermic vs. ectothermic) had nonsignificant impacts on both sequence evolution and mitogenomic size. Mitogenomic gene order rearrangements (GORR) were mostly positively correlated with mitogenomic size (R2 ≈ 20-30%). Longevity was not (negatively) correlated with sequence evolution in flatworms. The predominantly free-living "turbellaria" exhibited much shorter branches and faster-evolving mitogenomic architecture than parasitic Neodermata. As a result, "parasitism" had a strong explanatory power on the branch length variability (>90%), and there was a negative correlation between GORR and branch length. However, the stem branch of Neodermata comprised 63.6% of the total average branch length. This evolutionary period was also marked by a high rate of gene order rearrangements in the ancestral Neodermata. We discuss how this period of rapid evolution deep in the evolutionary history may have decoupled sequence evolution rates from longevity and GORR, and overestimated the explanatory power of "parasitism". This study shows that impacts of variables often vary across lineages, and stresses the importance accounting for the episodic nature of evolutionary patterns in studies of mitogenomic evolution.
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Affiliation(s)
- Ivan Jakovlić
- State Key Laboratory of Herbage Improvement and Grassland Agro-Ecosystems, and College of Ecology, Lanzhou University, Lanzhou, 730000, China
| | - Tong Ye
- State Key Laboratory of Herbage Improvement and Grassland Agro-Ecosystems, and College of Ecology, Lanzhou University, Lanzhou, 730000, China
| | - Hong Zou
- Key Laboratory of Aquaculture Disease Control, Ministry of Agriculture, and State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, 430072, China
| | - Fengyue Zhu
- National Agricultural Science Observing and Experimental Station of Chongqing, Chongqing, 401329, China
- Yangtze River Fisheries Research Institute, Chinese Academy of Fishery Science, Wuhan, 430073, China
| | - Yuying Shi
- State Key Laboratory of Herbage Improvement and Grassland Agro-Ecosystems, and College of Ecology, Lanzhou University, Lanzhou, 730000, China
| | - Yiwen Ma
- State Key Laboratory of Herbage Improvement and Grassland Agro-Ecosystems, and College of Ecology, Lanzhou University, Lanzhou, 730000, China
| | - Gui-Tang Wang
- Key Laboratory of Aquaculture Disease Control, Ministry of Agriculture, and State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, 430072, China
| | - Wen-Xiang Li
- Key Laboratory of Aquaculture Disease Control, Ministry of Agriculture, and State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, 430072, China
| | - Dong Zhang
- State Key Laboratory of Herbage Improvement and Grassland Agro-Ecosystems, and College of Ecology, Lanzhou University, Lanzhou, 730000, China.
- Key Laboratory of Biodiversity and Environment on the Qinghai-Tibetan Plateau, Ministry of Education, School of Ecology and Environment, Tibet University, Lhasa, 850011, China.
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2
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Scholz T. Gaps in parasitological research in the molecular era. Trends Parasitol 2024; 40:283-291. [PMID: 38429122 DOI: 10.1016/j.pt.2024.02.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2024] [Revised: 02/07/2024] [Accepted: 02/07/2024] [Indexed: 03/03/2024]
Abstract
We live in the age of molecular biology and '-omics', and molecular methods have opened up unimagined possibilities for biological research, including parasitology. However, too one-sided a focus on new approaches can lead to major gaps as less 'cool' topics are neglected. Selected areas of research are briefly discussed to highlight the gaps caused by the current excessive focus on molecular and '-omics' methods. It is crucial to combine both 'classical' and modern methods without neglecting the complexity of the interactions of parasites with their hosts and the environment (One Health concept), which is even more urgent in today's rapidly changing world. Parasitologists should be more involved in field studies and multidisciplinary assessment of parasites.
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Affiliation(s)
- Tomáš Scholz
- Institute of Parasitology, Biology Centre of the Czech Academy of Sciences, České Budějovice, Czech Republic.
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3
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Faltýnková A, Jouet D, Nielsen ÓK, Skírnisson K. First species record of Strigea falconis Szidat, 1928 (Trematoda, Strigeidae) from gyrfalcon Falco rusticolus in Iceland-pros and cons of a complex life cycle. Parasitol Res 2024; 123:147. [PMID: 38433153 PMCID: PMC10909778 DOI: 10.1007/s00436-024-08161-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2023] [Accepted: 02/10/2024] [Indexed: 03/05/2024]
Abstract
Strigea falconis is a common parasite of birds of prey and owls widely distributed in the Holarctic. We aimed to characterise S. falconis from Iceland via integrative taxonomic approach and to contribute to the understanding of its circulation in the Holarctic. We recovered adult S. falconis from two gyrfalcons (Falco rusticolus) collected in 2011 and 2012 in Iceland (Reykjanes Peninsula, Westfjords) and characterised them by morphological and molecular genetic (D2 of rDNA, cox1, ND1 of the mDNA) methods. We provide the first species record of S. falconis in Iceland which to the best of our knowledge is its northernmost distributional range. The presence of S. falconis in Iceland is surprising, as there are no suitable intermediate hosts allowing completion of its life cycle. Gyrfalcons are fully sedentary in Iceland; thus, the only plausible explanation is that they acquired their infection by preying upon migratory birds arriving from Europe. Our data indicate that the most likely candidates are Anseriformes and Charadriiformes. Also, we corroborate the wide geographical distribution of S. falconis, as we found a high degree of similarity between our haplotypes and sequences of mesocercariae from frogs in France and of a metacercaria from Turdus naumanni in Japan, and adults from Buteo buteo and Circus aeruginosus from the Czech Republic. The case of Strigea falconis shows the advantages of a complex life cycle and also depicts its pitfalls when a parasite is introduced to a new area with no suitable intermediate hosts. In Iceland, gyrfalcons are apparently dead-end hosts for S. falconis.
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Affiliation(s)
- Anna Faltýnková
- Department of Forest Ecology, Faculty of Forestry and Wood Technology, Mendel University in Brno, Zemědělská 3, Brno, 613 00, Czech Republic.
| | - Damien Jouet
- ESCAPE UR7510, USC ANSES PETARD, Faculty of Pharmacy, University of Reims Champagne-Ardenne, 51 Rue Cognacq-Jay, 51096, Reims Cedex, France
| | | | - Karl Skírnisson
- Laboratory of Parasitology, Institute for Experimental Pathology, Keldur, University of Iceland, IS-112, Reykjavík, Iceland
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Franco-Bodek T, Barradas-Ortiz C, Negrete-Soto F, Rodríguez-Canul R, Lozano-Álvarez E, Briones-Fourzán P. Effects of Cymatocarpus solearis (Trematoda: Brachycoeliidae) on its second intermediate host, the Caribbean spiny lobster Panulirus argus. PLoS One 2023; 18:e0287097. [PMID: 37773971 PMCID: PMC10540948 DOI: 10.1371/journal.pone.0287097] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2023] [Accepted: 05/29/2023] [Indexed: 10/01/2023] Open
Abstract
Many digenean trematodes require three hosts to complete their life cycle. For Cymatocarpus solearis (Brachycoeliidae), the first intermediate host is unknown; the Caribbean spiny lobster Panulirus argus is a second intermediate host, and the loggerhead turtle Caretta caretta, a lobster predator, is the definitive host. Trophically-transmitted parasites may alter the behavior or general condition of intermediate hosts in ways that increase the hosts' rates of consumption by definitive hosts. Here, we examined the effects of infection by C. solearis on P. argus by comparing several physiological and behavioral variables among uninfected lobsters (0 cysts) and lobsters with light (1-10 cysts), moderate (11-30 cysts), and heavy (>30 cysts) infections. Physiological variables were hepatosomatic index, growth rate, hemocyte count, concentration in hemolymph of cholesterol, protein, albumin, glucose, dopamine (DA) and serotonin (5-HT). Behavioral variables included seven components of the escape response (delay to escape, duration of swimming bout, distance traveled in a swimming bout, swim velocity, acceleration, force exerted, and work performed while swimming). There was no relationship between lobster size or sex and number of cysts. Significant differences among the four lobster groups occurred only in concentration of glucose (lower in heavily infected lobsters) and 5-HT (higher in heavily and moderately infected lobsters) in plasma. As changes in 5-HT concentration can modify the host's activity patterns or choice of microhabitat, our results suggest that infection with C. solearis may alter the behavior of spiny lobsters, potentially increasing the likelihood of trophic transmission of the parasite to the definitive host.
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Affiliation(s)
- Tomás Franco-Bodek
- Posgrado en Ciencias del Mar y Limnología, Universidad Nacional Autónoma de México, Ciudad Universitaria, Ciudad de México, Mexico
| | - Cecilia Barradas-Ortiz
- Unidad Académica de Sistemas Arrecifales, Instituto de Ciencias del Mar y Limnología, Universidad Nacional Autónoma de México, Puerto Morelos, Quintana Roo, Mexico
| | - Fernando Negrete-Soto
- Unidad Académica de Sistemas Arrecifales, Instituto de Ciencias del Mar y Limnología, Universidad Nacional Autónoma de México, Puerto Morelos, Quintana Roo, Mexico
| | - Rossanna Rodríguez-Canul
- Laboratorio de Inmunología y Biología Molecular, Departamento de Recursos del Mar, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional-Unidad Mérida, Mérida, Yucatán, Mexico
| | - Enrique Lozano-Álvarez
- Unidad Académica de Sistemas Arrecifales, Instituto de Ciencias del Mar y Limnología, Universidad Nacional Autónoma de México, Puerto Morelos, Quintana Roo, Mexico
| | - Patricia Briones-Fourzán
- Unidad Académica de Sistemas Arrecifales, Instituto de Ciencias del Mar y Limnología, Universidad Nacional Autónoma de México, Puerto Morelos, Quintana Roo, Mexico
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Charoennitiwat V, Chaisiri K, Ampawong S, Laoungbua P, Chanhome L, Vasaruchapong T, Tawan T, Thaenkham U, Ratnarathorn N. Redescription and new record of Paracapillaria ( Ophidiocapillaria) najae (Nematoda: Trichuroidea) in the monocled cobra Naja kaouthia from central Thailand: morphological and molecular insights. Parasitology 2023; 150:901-910. [PMID: 37519244 PMCID: PMC10577661 DOI: 10.1017/s0031182023000707] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2023] [Revised: 07/18/2023] [Accepted: 07/18/2023] [Indexed: 08/01/2023]
Abstract
The parasitic nematode Paracapillaria (Ophidiocapillaria) najae De, 1998, found in the Indian cobra Naja naja is redescribed and re-illustrated in the present study. The monocled cobra Naja kaouthia was discovered to be a new host for this parasite in central Thailand. A comprehensive description extending the morphological and molecular characteristics of the parasites is provided to aid species recognition in future studies. The morphometric characters of 41 parasites collected from 5 cobra specimens are compared with those described in the original studies. Phylogenetic analyses using mitochondrial cytochrome c oxidase subunit 1 and nuclear 18S ribosomal RNA genes were performed to provide novel information on the systematics of P. najae. Similar characteristics were observed in the examined nematode samples, despite being found in different hosts, confirming their identity as P. najae. The molecular genetic results support the species status of P. najae, indicating P. najae is well defined and separated from other related nematode species in the family Capillariidae. Morphological descriptions, genetic sequences, evolutionary relationships among capillariids and new host and distribution records of P. najae are discussed. Paracapillaria najae specimens found in the Thai cobra had some morphological variation, and sexual size dimorphism was also indicated. Paracapillaria najae was found to infect various cobra host species and appeared to be common throughout the Oriental regions, consistent with its hosts' distribution.
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Affiliation(s)
| | - Kittipong Chaisiri
- Department of Helminthology, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Sumate Ampawong
- Department of Tropical Pathology, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Panithi Laoungbua
- Snake Farm, Queen Saovabha Memorial Institute, The Thai Red Cross Society, Bangkok, Thailand
| | - Lawan Chanhome
- Snake Farm, Queen Saovabha Memorial Institute, The Thai Red Cross Society, Bangkok, Thailand
| | - Taksa Vasaruchapong
- Snake Farm, Queen Saovabha Memorial Institute, The Thai Red Cross Society, Bangkok, Thailand
| | - Tanapong Tawan
- Snake Farm, Queen Saovabha Memorial Institute, The Thai Red Cross Society, Bangkok, Thailand
| | - Urusa Thaenkham
- Department of Helminthology, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Napat Ratnarathorn
- Animal Systematics and Molecular Ecology Laboratory, and Applied Animal Science Laboratory, Department of Biology, Faculty of Science, Mahidol University, Bangkok, Thailand
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6
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Salloum PM, Jorge F, Dheilly NM, Poulin R. Adoption of alternative life cycles in a parasitic trematode is linked to microbiome differences. Biol Lett 2023; 19:20230091. [PMID: 37282491 PMCID: PMC10244958 DOI: 10.1098/rsbl.2023.0091] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2023] [Accepted: 05/23/2023] [Indexed: 06/08/2023] Open
Abstract
For parasites with complex multi-host life cycles, the facultative truncation of the cycle represents an adaptation to challenging conditions for transmission. However, why certain individuals are capable of abbreviating their life cycle while other conspecifics are not remains poorly understood. Here, we test whether conspecific trematodes that either follow the normal three-host life cycle or skip their final host by reproducing precociously (via progenesis) in an intermediate host differ in the composition of their microbiomes. Characterization of bacterial communities based on sequencing of the V4 hypervariable region of the 16S SSU rRNA gene revealed that the same bacterial taxa occur in both normal and progenetic individuals, independent of host identity and temporal variation. However, all bacterial phyla recorded in our study, and two-thirds of bacterial families, differed in abundance between the two morphs, with some achieving higher abundance in the normal morph and others in the progenetic morph. Although the evidence is purely correlative, our results reveal a weak association between microbiome differences and intraspecific plasticity in life cycle pathways. Advances in functional genomics and experimental microbiome manipulation will allow future tests of the significance of these findings.
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Affiliation(s)
| | - Fátima Jorge
- Otago Micro and Nano Imaging, Electron Microscopy Unit, University of Otago, Dunedin 9016, New Zealand
| | - Nolwenn M. Dheilly
- School of Marine and Atmospheric Sciences, Stony Brook University, Stony Brook, NY 11794, USA
- ANSES, Agence Nationale de Sécurité Sanitaire de l'Alimentation, de l'Environnement et du Travail - Laboratoire de Ploufragan-Plouzané, Unité Génétique Virale de Biosécurité, 22440, Ploufragan, France
| | - Robert Poulin
- Department of Zoology, University of Otago, Dunedin 9016, New Zealand
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Al-Ghafli H, Barribeau SM. Double trouble: trypanosomatids with two hosts have lower infection prevalence than single host trypanosomatids. Evol Med Public Health 2023; 11:202-218. [PMID: 37404250 PMCID: PMC10317189 DOI: 10.1093/emph/eoad014] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2022] [Revised: 04/21/2023] [Indexed: 07/06/2023] Open
Abstract
Trypanosomatids are a diverse family of protozoan parasites, some of which cause devastating human and livestock diseases. There are two distinct infection life cycles in trypanosomatids; some species complete their entire life cycle in a single host (monoxenous) while others infect two hosts (dixenous). Dixenous trypanosomatids are mostly vectored by insects, and the human trypanosomatid diseases are caused mainly by vectored parasites. While infection prevalence has been described for subsets of hosts and trypanosomatids, little is known about whether monoxenous and dixenous trypanosomatids differ in infection prevalence. Here, we use meta-analyses to synthesise all published evidence of trypanosomatid infection prevalence for the last two decades, encompassing 931 unique host-trypansomatid systems. In examining 584 studies that describe infection prevalence, we find, strikingly, that monoxenous species are two-fold more prevalent than dixenous species across all hosts. We also find that dixenous trypanosomatids have significantly lower infection prevalence in insects than their non-insect hosts. To our knowledge, these results reveal for the first time, a fundamental difference in infection prevalence according to host specificity where vectored species might have lower infection prevalence as a result of a potential 'jack of all trades, master of none' style trade-off between the vector and subsequent hosts.
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Affiliation(s)
- Hawra Al-Ghafli
- Department of Evolution, Ecology and Behaviour, Institute of Infection, Veterinary, and Ecological Sciences, University of Liverpool, Liverpool, UK
| | - Seth M Barribeau
- Corresponding author. Department of Evolution, Ecology and Behaviour, Institute of Infection, Veterinary, and Ecological Sciences, University of Liverpool, Liverpool, UK. E-mail:
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microRNAs: Critical Players during Helminth Infections. Microorganisms 2022; 11:microorganisms11010061. [PMID: 36677353 PMCID: PMC9861972 DOI: 10.3390/microorganisms11010061] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2022] [Revised: 12/19/2022] [Accepted: 12/22/2022] [Indexed: 12/28/2022] Open
Abstract
microRNAs (miRNAs) are a group of small non-coding RNAs that regulate gene expression post-transcriptionally through their interaction with the 3' untranslated regions (3' UTR) of target mRNAs, affecting their stability and/or translation. Therefore, miRNAs regulate biological processes such as signal transduction, cell death, autophagy, metabolism, development, cellular proliferation, and differentiation. Dysregulated expression of microRNAs is associated with infectious diseases, where miRNAs modulate important aspects of the parasite-host interaction. Helminths are parasitic worms that cause various neglected tropical diseases affecting millions worldwide. These parasites have sophisticated mechanisms that give them a surprising immunomodulatory capacity favoring parasite persistence and establishment of infection. In this review, we analyze miRNAs in infections caused by helminths, emphasizing their role in immune regulation and its implication in diagnosis, prognosis, and the development of therapeutic strategies.
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De Vivo M, Huang J. Modeling the geographical distributions of Chordodes formosanus and its mantis hosts in Taiwan, with considerations for their niche overlaps. Ecol Evol 2022; 12:e9546. [PMID: 36447597 PMCID: PMC9702995 DOI: 10.1002/ece3.9546] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2022] [Revised: 10/28/2022] [Accepted: 11/08/2022] [Indexed: 11/29/2022] Open
Abstract
Species distribution models (SDMs) have conventionally been used for evaluating the distribution of individual species, but they can also be used, through comparing different SDMs, to evaluate the geographic similarity between taxa. In this study, we used a parasite and host system to infer the geographic overlaps between species with tight biological interaction, for example, parasites and their obligate host. Specifically, we used the horsehair worm Chordodes formosanus and its three mantis hosts to study the extent of niche overlap. We retrieved presence points for the host species and the parasite, and then we built SDMs with MaxEnt implemented in ENMeval using selected bioclim variables (based on variance inflation factor values) at 30s scale. The models showed that the hosts and parasite do not occur in the high elevation areas in Taiwan, which is expected based on their biology. Interestingly, the predicted parasite distribution included areas without collection records, implying local extinction or sampling bias. We subsequently evaluated niche overlap between hosts and the parasite according to five similarity indices (Schoener's D, I statistic, relative rank, Pearson correlation coefficient, and the rank correlation coefficient rho). Our models showed a high similarity of SDM predictions between hosts and the parasite. There were differences among metrics for which host shared the highest similarity with the parasite, but the majority of the results indicated that the Japanese boxing mantis had the highest niche similarity with the horsehair worm. The choice of the niche overlap metric to use can uncover information on the parasite's ecology, which can be important for endangered species. SDMs are reliable tools for host and parasite conservation management and could help improve our understanding of parasite biology and ecology.
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Affiliation(s)
- Mattia De Vivo
- Biodiversity Research CenterAcademia SinicaTaipeiTaiwan
- Department of Life ScienceNational Taiwan Normal UniversityTaipeiTaiwan
- Biodiversity Program, Taiwan International Graduate ProgramAcademia Sinica and National Taiwan Normal UniversityTaipeiTaiwan
| | - Jen‐Pan Huang
- Biodiversity Research CenterAcademia SinicaTaipeiTaiwan
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10
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Benesh DP, Chubb JC, Parker GA. Adaptive division of growth and development between hosts in helminths with two-host life cycles. Evolution 2022; 76:1971-1985. [PMID: 35860949 DOI: 10.1111/evo.14574] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2022] [Revised: 05/11/2022] [Accepted: 05/25/2022] [Indexed: 01/22/2023]
Abstract
Parasitic worms (helminths) with complex life cycles divide growth and development between successive hosts. Using data from 597 species of acanthocephalans, cestodes, and nematodes with two-host life cycles, we found that helminths with larger intermediate hosts were more likely to infect larger, endothermic definitive hosts, although some evolutionary shifts in definitive host mass occurred without changes in intermediate host mass. Life-history theory predicts parasites to shift growth to hosts in which they can grow rapidly and/or safely. Accordingly, helminth species grew relatively less as larvae and more as adults if they infected smaller intermediate hosts and/or larger, endothermic definitive hosts. Growing larger than expected in one host, relative to host mass/endothermy, was not associated with growing less in the other host, implying a lack of cross-host trade-offs. Rather, some helminth orders had both large larvae and large adults. Within these taxa, however, size at maturity in the definitive host was unaffected by changes to larval growth, as predicted by optimality models. Parasite life-history strategies were mostly (though not entirely) consistent with theoretical expectations, suggesting that helminths adaptively divide growth and development between the multiple hosts in their complex life cycles.
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Affiliation(s)
- Daniel P Benesh
- Department of Molecular Parasitology, Humboldt University, 10115, Berlin, Germany.,Leibniz-Institute of Freshwater Ecology and Inland Fisheries (IGB), 12587, Berlin, Germany
| | - James C Chubb
- Department of Evolution, Ecology and Behaviour, University of Liverpool, Liverpool, L69 7ZB, United Kingdom
| | - Geoff A Parker
- Department of Evolution, Ecology and Behaviour, University of Liverpool, Liverpool, L69 7ZB, United Kingdom
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Leung TLF. Economies of parasite body size. Curr Biol 2022; 32:R645-R649. [PMID: 35728546 DOI: 10.1016/j.cub.2022.01.059] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Parasitism has independently evolved multiple times across the entire tree of life, and there are numerous parasitic representatives from every major eukaryote kingdom. In animals alone, parasitism has independently evolved at least 200 times. If there are any organisms that one might think would have access to limitless resources, it would be parasites. You would think that living in or on the body of their host, which serves as both a habitat and a food source, would provide parasites with bountiful resources to maximise every aspect of their existence, especially reproduction. But parasitism is not a loophole out of life history trade-offs. There is still a finite amount of resources that a parasite can obtain and allocate to its many needs. Living in a resource-rich environment has allowed many parasites to grow to sizes that are of multiple orders of magnitude larger than their free-living relatives. But that does not mean that the underlying economy of nature and its limitations are inapplicable to parasites.
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Affiliation(s)
- Tommy L F Leung
- Zoology, School of Environmental and Rural Science, University of New England, Armidale, NSW 2351, Australia.
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12
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Liu W, Chen H. Idea paper: Trophic transmission as a potential mechanism underlying the distribution of parasite diversity in food webs. Ecol Res 2022. [DOI: 10.1111/1440-1703.12324] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Affiliation(s)
- Wei‐Chung Liu
- Institute of Statistical Science Academia Sinica Taipei Taiwan
| | - Hsuan‐Wien Chen
- Department of Biological Resources National Chiayi University Chiayi City Taiwan
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Yevstafieva V, Khorolskyi A, Kravchenko S, Melnychuk V, Nikiforova O, Reshetylo O. Features of the exogenic development of Passalurus ambiguus (Nematoda, Oxyuroidae) at different temperature regimes. BIOSYSTEMS DIVERSITY 2022. [DOI: 10.15421/012207] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
Abstract
Passalurosis is a prevalent disease among helminthiases of domestic rabbits. This invasion is caused by the nematode Passalurus ambiguus (Nematoda, Oxyuroidae), which is cosmopolitan and localized in the cecum and colon of rabbits. Passalurosis is highly contagious and capable of unlimited spread, due to the biological characteristics of its pathogen, such as the conditions that ensure maximum preservation of parasites at exogenous stages of their development. Experimental research in the laboratory established the timing of development of P. ambiguus eggs isolated from the gonads of female helminths, depending on temperature regimes and features of their growth and development. According to the morphological features of Passalurus eggs, four stages were distinguished in their exogenous development: zygote, cleavage and formation of blastomeres, formation of larvae and motile larvae. Depending on the cultivation temperature, the duration of embryogenesis ranged from 4 to 9 days, and egg viability ranged from 59.3% to 72.7%. The most favourable temperature regime for the development of P. ambiguus eggs was the temperature of 35 °C, at which 72.7% of eggs with motile larvae were formed within 4 days. At this temperature, the zygote stage lasted for 1 day of cultivation, the stage of cleaving and formation of blastomeres occurred on days 1–2, the stage of larval formation on days 1–3, and the stage of formation of motile larva on days 3–4. At lower temperatures, the term of development of Passalurus eggs increased, and the number of viable eggs decreased. At temperatures of 30 °С and 25 °С, the development of Passalurus eggs took place during 5 and 7 days, respectively, and the viability was 66.7% and 62.7%. At these temperatures, the zygote stage lasted 1–2 and 1–3 days, the stage of cleaving and formation of blastomeres occurred on days 1–3 and 1–4, the stage of larval formation lasted from days 2–4 and 2–6, and the stage of formation of motile larvae took place on days 3–5 and 4–7, respectively. The least favourable temperature for the development of P. ambiguus eggs was the temperature of 20 °С, at which the formation of motile larvae occurred in 9 days, and their viability was only 59.3%. At this temperature, the zygote stage lasted 1–4 days, the stage of cleaving and blastomere formation occurred on days 2–6, and the larval formation stage on days 3–8, and the motile larval stage happened on days 5–9. The growth and development of P. ambiguus eggs was accompanied by significant changes in morphometric parameters, such as the increase in egg width and thinning of egg shell at the egg shell plug. The obtained data will allow preventive measures to be effectively implemented on rabbit farms that are susceptible to pinworms, taking into account the terms of exogenous development of pathogens in different seasons.
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Benesh DP, Chubb JC, Lafferty KD, Parker GA. Complex life-cycles in trophically transmitted helminths: Do the benefits of increased growth and transmission outweigh generalism and complexity costs? CURRENT RESEARCH IN PARASITOLOGY & VECTOR-BORNE DISEASES 2022; 2:100085. [PMID: 35310018 PMCID: PMC8928126 DOI: 10.1016/j.crpvbd.2022.100085] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/24/2021] [Revised: 02/24/2022] [Accepted: 02/24/2022] [Indexed: 12/01/2022]
Abstract
Why do so many parasitic worms have complex life-cycles? A complex life-cycle has at least two hypothesized costs: (i) worms with longer life-cycles, i.e. more successive hosts, must be generalists at the species level, which might reduce lifetime survival or growth, and (ii) each required host transition adds to the risk that a worm will fail to complete its life-cycle. Comparing hundreds of trophically transmitted acanthocephalan, cestode, and nematode species with different life-cycles suggests these costs are weaker than expected. Helminths with longer cycles exhibit higher species-level generalism without impaired lifetime growth. Further, risk in complex life-cycles is mitigated by increasing establishment rates in each successive host. Two benefits of longer cycles are transmission and production. Longer cycles normally include smaller (and thus more abundant) first hosts that are likely to consume parasite propagules, as well as bigger (and longer-lived) definitive hosts, in which adult worms grow to larger and presumably more fecund reproductive sizes. Additional factors, like host immunity or dispersal, may also play a role, but are harder to address. Given the ubiquity of complex life-cycles, the benefits of incorporating or retaining hosts in a cycle must often exceed the costs. Comparing helminth species hints at the costs and benefits of complex life-cycles. Generalism and survival costs in longer life-cycles are weaker than expected. Longer life-cycles have growth and transmission benefits. The benefits of a complex life-cycle must often exceed the costs.
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Affiliation(s)
- Daniel P. Benesh
- Humboldt University of Berlin, Molecular Parasitology, Philippstr. 13, Haus 14, 10115, Berlin, Germany
- Leibniz-Institute of Freshwater Ecology and Inland Fisheries (IGB), Müggelseedamm 310, 12587, Berlin, Germany
- Corresponding author. Humboldt University of Berlin, Molecular Parasitology, Philippstr. 13, Haus 14, 10115, Berlin, Germany.
| | - James C. Chubb
- Department of Evolution, Ecology and Behaviour, University of Liverpool, Liverpool, L69 7ZB, UK
| | - Kevin D. Lafferty
- Western Ecological Research Center, U.S. Geological Survey, at Marine Science Institute, University of California, Santa Barbara, CA, 93106, USA
| | - Geoff A. Parker
- Department of Evolution, Ecology and Behaviour, University of Liverpool, Liverpool, L69 7ZB, UK
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Rich but random: parasite communities of snouted treefrog, Scinax fuscovarius (Anura: Hylidae), in Bodoquena Mountains, western Brazil. Parasitol Res 2021; 121:11-19. [PMID: 34820717 DOI: 10.1007/s00436-021-07378-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2020] [Accepted: 11/08/2021] [Indexed: 10/19/2022]
Abstract
Hosts represent discrete habitats that contain finite parasite communities, and individual hosts can be used as replicates in parasitism studies, such as investigations of the processes that mediate the formation of parasite communities. However, within a single host population, there may be singularities among individuals that affect parasite contact rates. Accordingly, the goals of the present study were to document the parasites associated with the small treefrog Scinax fuscovarius, to verify possible variation and co-occurrences in parasite infracommunities, and to assess the effects of host characteristics (size and sex) on infracommunity structure. Treefrog specimens (n = 75) were collected from the Bodoquena Mountains in Mato Grosso do Sul, Brazil. After collection, the specimens were transported to the laboratory, and examined for parasitic. The parasites found were removed, fixed, and identified. Patterns in parasite infracommunity organization were analyzed using the checkerboard score index, which was calculated using a presence-absence matrix. The matrix was randomized under the null hypothesis that the infracommunities independently represent the component community. Forty-two (56%) of the individuals harbored at least one parasite, and a total of 500 metazoan parasites were recovered, with a particularly rich composite community of 18 taxa, including 13 nematodes, two trematodes, one cestode, one oligochaete, and one mite larvae. The parasite species were randomly distributed among the infracommunities, with no evidence of co-occurrence, segregation, or aggregation. However, both body size and sex influenced infection, with larger hosts harboring more parasites and parasites were more abundant in male specimens and more species rich in female specimens. These results suggest that the parasite infracommunities of S. fuscovarius are shaped by both random factors and individual host characteristics.
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Research on helminths from Mexican amphibians: gaps, trends, and biases. J Helminthol 2021; 95:e67. [PMID: 34802480 DOI: 10.1017/s0022149x21000614] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
We present a taxonomic, spatial, and thematic overview of the current state of knowledge on helminth parasites of Mexican amphibians. Sixty-six host species have been studied so far, representing 17.5% of the amphibian species distributed in Mexico. A total of 139 nominal species of helminths - 68 platyhelminths, 62 nematodes, three acanthocephalans, three annelids (hirudineans), and three arthropods (pentastomids) - have been recorded parasitizing these hosts. Most taxa found in larval stages have not been identified at the species level. The gastrointestinal nematode Aplectana itzocanensis exhibits the broadest host range, while the bladder fluke Gorgoderina attenuata and A. itzocanensis show the widest geographic distribution. Our analysis of helminthological studies evidenced gaps and biases on research efforts that have been devoted to relatively few host species, regions, and approaches. Most helminthological records come from two species, the cane toad Rhinella marina and the Montezuma's frog Lithobates montezumae, and most studies have focused on describing the helminth fauna of a host species in a particular location or on the description of new helminth species. The highest proportion of records corresponds to the Veracruzan biogeographic province, and helminth richness is significantly correlated with host richness and with total amphibian richness by biogeographic province. Only three provinces (Yucatan Peninsula, Pacific Lowlands, and Baja Californian) have positive, yet still low helminth species discovery effort. Based on our findings, we recommend pursuing research approaches unexplored in Mexico and we provide guidelines to improve research on helminths parasitizing amphibians.
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