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Neal AT, Stettner M, Ortega-Cotto R, Dieringer D, Reed LC. Freshwater trematodes differ from marine trematodes in patterns connected with division of labor. PeerJ 2024; 12:e17211. [PMID: 38623495 PMCID: PMC11017974 DOI: 10.7717/peerj.17211] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2023] [Accepted: 03/18/2024] [Indexed: 04/17/2024] Open
Abstract
Background Prior research suggests that trematode rediae, a developmental stage of trematode parasites that reproduce clonally within a snail host, show evidence of division of labor (DOL). Single-species infections often have two morphologically distinct groups: small rediae, the 'soldiers', are active, aggressive, and do not appear to reproduce; large rediae, the 'reproductives', are larger, sluggish, and full of offspring. Most data supporting DOL come from trematodes infecting marine snails, while data from freshwater trematodes are more limited and generally do not supported DOL. The shorter lifespan typical of freshwater snails may partially explain this difference: defending a short-lived host at the expense of reproduction likely provides few advantages. Here, we present data from sixty-one colonies spanning twenty species of freshwater trematode exploring morphological and behavioral patterns commonly reported from marine trematodes believed to have DOL. Methods Trematode rediae were obtained from sixty-one infected snails collected in central Vermont, USA. A portion of the COI gene was sequenced to make tentative species identifications ('COI species'). Samples of rediae were photographed, observed, and measured to look for DOL-associated patterns including a bimodal size distribution, absence of embryos in small rediae, and pronounced appendages and enlarged pharynges (mouthparts) in small rediae. Additional rediae were used to compare activity levels and likelihood to attack heterospecific trematodes in large vs. small rediae. Results Many of the tests for DOL-associated patterns showed mixed results, even among colonies of the same COI species. However, we note a few consistent patterns. First, small rediae of most colonies appeared capable of reproduction, and we saw no indication (admittedly based on a small sample size and possibly insufficient attack trial methodology) that small rediae were more active or aggressive. This differs from patterns reported from most marine trematodes. Second, the small rediae of most colonies had larger pharynges relative to their body size than large rediae, consistent with marine trematodes. We also observed that colonies of three sampled COI species appear to produce a group of large rediae that have distinctly large pharynges. Conclusions We conclude that these freshwater species likely do not have a group of specialized non-reproductive soldiers because small rediae of at least some colonies in almost every species do appear to produce embryos. We cannot rule out the possibility that small rediae act as a temporary soldier caste. We are intrigued by the presence of rediae with enlarged pharynges in some species and propose that they may serve an adaptive role, possibly similar to the defensive role of small 'soldier' rediae of marine trematodes. Large-pharynx rediae have been documented in other species previously, and we encourage future efforts to study these large-pharynx rediae.
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2
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Brian JI, Aldridge DC. Host and parasite identity interact in scale-dependent fashion to determine parasite community structure. Oecologia 2024; 204:199-211. [PMID: 38206416 PMCID: PMC10830602 DOI: 10.1007/s00442-023-05499-3] [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: 01/11/2022] [Accepted: 12/10/2023] [Indexed: 01/12/2024]
Abstract
Understanding the ecological assembly of parasite communities is critical to characterise how changing host and environmental landscapes will alter infection dynamics and outcomes. However, studies frequently assume that (a) closely related parasite species or those with identical life-history strategies are functionally equivalent, and (b) the same factors will drive infection dynamics for a single parasite across multiple host species, oversimplifying community assembly patterns. Here, we challenge these two assumptions using a naturally occurring host-parasite system, with the mussel Anodonta anatina infected by the digenean trematode Echinoparyphium recurvatum, and the snail Viviparus viviparus infected by both E. recurvatum and Echinostoma sp. By analysing the impact of temporal parasite dispersal, host species and size, and the impact of coinfection (moving from broader environmental factors to within-host dynamics), we show that neither assumption holds true, but at different ecological scales. The assumption that closely related parasites can be functionally grouped is challenged when considering dispersal to the host (i.e. larger scales), while the assumption that the same factors will drive infection dynamics for a single parasite across multiple host species is challenged when considering within-host interspecific competition (i.e. smaller scales). Our results demonstrate that host identity, parasite identity and ecological scale require simultaneous consideration in studies of parasite community composition and transmission.
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Affiliation(s)
- Joshua I Brian
- Aquatic Ecology Group, Department of Zoology, University of Cambridge, The David Attenborough Building, Cambridge, CB2 3QZ, UK.
- Department of Geography, Bush House North East, King's College London, London, WC2B 4BG, UK.
| | - David C Aldridge
- Aquatic Ecology Group, Department of Zoology, University of Cambridge, The David Attenborough Building, Cambridge, CB2 3QZ, UK
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3
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Hechinger RF, Metz DCG. Social evolution: Diverse divisions of labor in trematode parasites. Curr Biol 2023; 33:R1238-R1240. [PMID: 38052175 DOI: 10.1016/j.cub.2023.10.029] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/07/2023]
Abstract
Some animal societies solve problems, like foraging or defense, by cooperatively dividing labor. A new discovery highlights that trematodes are unique in forming different societies at multiple parts of their complex life cycle with distinct divisions of labor to solve different problems.
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Affiliation(s)
- Ryan F Hechinger
- Scripps Institution of Oceanography, University of California San Diego, La Jolla, CA, USA.
| | - Daniel C G Metz
- School of Biological Sciences, University of Nebraska-Lincoln, Lincoln, NE, USA
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4
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Jorge F, Dheilly NM, Froissard C, Poulin R. Association between parasite microbiomes and caste development and colony structure in a social trematode. Mol Ecol 2022; 31:5608-5617. [PMID: 36004565 PMCID: PMC9826137 DOI: 10.1111/mec.16671] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2022] [Revised: 08/17/2022] [Accepted: 08/19/2022] [Indexed: 01/11/2023]
Abstract
Division of labour through the formation of morphologically and functionally distinct castes is a recurring theme in the evolution of animal sociality. The mechanisms driving the differentiation of individuals into distinct castes remain poorly understood, especially for animals forming clonal colonies. We test the association between microbiomes and caste formation within the social trematode Philophthalmus attenuatus, using a metabarcoding approach targeting the bacterial 16S SSU rRNA gene. Clonal colonies of this trematode within snail hosts comprise large reproductive individuals which produce dispersal stages, and small, non-reproducing soldiers which defend the colony against invaders. In colonies extracted directly from field-collected snails, reproductives harboured more diverse bacterial communities than soldiers, and reproductives and soldiers harboured distinct bacterial communities, at all taxonomic levels considered. No single bacterial taxon showed high enough prevalence in either soldiers or reproductives to be singled out as a key driver, indicating that the whole microbial community contributes to these differences. Other colonies were experimentally exposed to antibiotics to alter their bacterial communities, and sampled shortly after treatment and weeks later after allowing for turnover of colony members. At those time points, bacterial communities of the two castes still differed across all antibiotic treatments; however, the caste ratio within colonies changed: after antibiotic disruption and turnover of individuals, new individuals were more likely to become reproductives than in undisturbed control colonies. Our results reveal that each caste has a distinct microbiome; whether the social context affects the microbiota, or whether microbes contribute to modulating the phenotype of individuals, remains to be determined.
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Affiliation(s)
- Fátima Jorge
- Otago Micro and Nano Imaging, Electron Microscopy UnitUniversity of OtagoDunedinNew Zealand
| | - Nolwenn M. Dheilly
- School of Marine and Atmospheric SciencesStony Brook UniversityStony BrookNew YorkUSA,Unité Génétique Virale de Biosécurité, Agence Nationale de Sécurité Sanitaire de l'Alimentation, de l'Environnement et du Travail ‐ Laboratoire de Ploufragan‐PlouzanéANSESPloufraganFrance
| | | | - Robert Poulin
- Department of ZoologyUniversity of OtagoDunedinNew Zealand
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5
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A colony-level optimization model provides a potential mechanism for the evolution of novel castes in eusocial ant colonies. Heliyon 2022; 8:e09882. [PMID: 35815139 PMCID: PMC9260618 DOI: 10.1016/j.heliyon.2022.e09882] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2020] [Revised: 12/01/2021] [Accepted: 06/30/2022] [Indexed: 11/23/2022] Open
Abstract
Ant species often have multiple morphologically distinct ‘castes’ within a single colony. Given that most of these castes are involved in non-reproductive tasks, and since such individuals thus never reproduce, the question of how ant castes can evolve is a non-trivial one. Over the years, several models have been proposed in order to explain the evolution of castes in ant colonies. Here, we attempt to answer this question using an economics-based approach, developing an optimization model that implements adaptation and selection at the colony level. We argue that due to the nature of ant colonies, selection is shifted to the group level, and, due to this, individual ants are sheltered from negative selection. We show that our framework can explain the evolution of novel castes in ant colonies, and discuss the novelty of our model with regard to previous models that have been proposed. We also show that our model is consistent with several empirical observations of ant colonies.
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6
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Laidemitt MR, Gleichsner AM, Ingram CD, Gay SD, Reinhart EM, Mutuku MW, Oraro P, Minchella DJ, Mkoji GM, Loker ES, Steinauer ML. Host preference of field‐derived
Schistosoma mansoni
is influenced by snail host compatibility and infection status. Ecosphere 2022; 13. [PMID: 36285193 PMCID: PMC9592064 DOI: 10.1002/ecs2.4004] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Schistosome parasites cause a chronic inflammatory disease in humans, and recent studies have emphasized the importance of control programs for understanding the aquatic phases of schistosomiasis transmission. The host-seeking behavior of larval schistosomes (miracidia) for their snail intermediate hosts plays a critical role in parasite transmission. Using field-derived strains of Kenyan snails and parasites, we tested two main hypotheses: (1) Parasites prefer the most compatible host, and (2) parasites avoid hosts that are already infected. We tested preference to three Biomphalaria host snail taxa (B. pfeifferi, B. sudanica, and B. choanomphala), using allopatric and sympatric Schistosoma mansoni isolates and two different nonhost snail species that co-occur with Biomphalaria, Bulinus globosus, and Physa acuta. We also tested whether schistosomes avoid snail hosts that are already infected by another trematode species and whether competitive dominance played a role in their behavior. Preference was assessed using two-way choice chambers and by visually counting parasites that moved toward competing stimuli. In pairwise comparisons, we found that S. mansoni did not always prefer the more compatible snail taxon, but never favored an incompatible host over a compatible host. While parasites preferred B. pfeifferi to the nonhost species B. globosus, they did not significantly prefer B. pfeifferi versus P. acuta, an introduced species in Kenya. Finally, we demonstrated that parasites avoid infected snails if the resident parasite was competitively dominant (Patagifer sp.), and preferred snails infected with subordinates (xiphidiocercariae) to uninfected snails. These results provide evidence of “fine tuning” in the ability of schistosome miracidia to detect hosts; however, they did not always select hosts that would maximize fitness. Appreciating such discriminatory abilities could lead to a better understanding of how ecosystem host and parasite diversity influences disease transmission and could provide novel control mechanisms to improve human health.
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Affiliation(s)
- Martina R. Laidemitt
- Center for Evolutionary and Theoretical Immunology, Department of Biology University of New Mexico Albuquerque New Mexico USA
| | - Alyssa M. Gleichsner
- Department of Biological Sciences State University of New York, College at Plattsburgh Plattsburgh New York USA
| | - Christopher D. Ingram
- College of Osteopathic Medicine of the Pacific Northwest Western University of Health Sciences Lebanon Oregon USA
| | - Steven D. Gay
- College of Osteopathic Medicine of the Pacific Northwest Western University of Health Sciences Lebanon Oregon USA
| | | | - Martin W. Mutuku
- Center for Biotechnology Research and Development Kenya Medical Research Institute (KEMRI) Nairobi Kenya
| | - Polycup Oraro
- Center for Biotechnology Research and Development Kenya Medical Research Institute (KEMRI) Nairobi Kenya
| | - Dennis J. Minchella
- Department of Biological Sciences Purdue University West Lafayette Indiana USA
| | - Gerald M. Mkoji
- Center for Biotechnology Research and Development Kenya Medical Research Institute (KEMRI) Nairobi Kenya
| | - Eric S. Loker
- Center for Evolutionary and Theoretical Immunology, Department of Biology University of New Mexico Albuquerque New Mexico USA
| | - Michelle L. Steinauer
- College of Osteopathic Medicine of the Pacific Northwest Western University of Health Sciences Lebanon Oregon USA
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7
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Soldánová M, Kundid P, Scholz T, Kristoffersen R, Knudsen R. Somatic Dimorphism in Cercariae of a Bird Schistosome. Pathogens 2022; 11:pathogens11030290. [PMID: 35335614 PMCID: PMC8953619 DOI: 10.3390/pathogens11030290] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2022] [Revised: 02/20/2022] [Accepted: 02/22/2022] [Indexed: 11/16/2022] Open
Abstract
Phenotypic polymorphism is a commonly observed phenomenon in nature, but extremely rare in free-living stages of parasites. We describe a unique case of somatic polymorphism in conspecific cercariae of the bird schistosome Trichobilharzia sp. “peregra”, in which two morphs, conspicuously different in their size, were released from a single Radix balthica snail. A detailed morphometric analysis that included multiple morphological parameters taken from 105 live and formalin-fixed cercariae isolated from several naturally infected snails provided reliable evidence for a division of all cercariae into two size groups that contained either large or small individuals. Large morph (total body length of 1368 and 1339 μm for live and formalin-fixed samples, respectively) differed significantly nearly in all morphological characteristics compared to small cercariae (total body length of 976 and 898 μm for live and formalin samples, respectively), regardless of the fixation method. Furthermore, we observed that small individuals represent the normal/commonly occurring phenotype in snail populations. The probable causes and consequences of generating an alternative, much larger phenotype in the parasite infrapopulation are discussed in the context of transmission ecology as possible benefits and disadvantages facilitating or preventing the successful completion of the life cycle.
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Affiliation(s)
- Miroslava Soldánová
- Institute of Parasitology, Biology Centre of the Czech Academy of Sciences, 370 05 České Budějovice, Czech Republic; (P.K.); (T.S.)
- Correspondence:
| | - Petra Kundid
- Institute of Parasitology, Biology Centre of the Czech Academy of Sciences, 370 05 České Budějovice, Czech Republic; (P.K.); (T.S.)
- Department of Parasitology, Faculty of Science, University of South Bohemia in České Budějovice, 370 05 České Budějovice, Czech Republic
| | - Tomáš Scholz
- Institute of Parasitology, Biology Centre of the Czech Academy of Sciences, 370 05 České Budějovice, Czech Republic; (P.K.); (T.S.)
- Department of Parasitology, Faculty of Science, University of South Bohemia in České Budějovice, 370 05 České Budějovice, Czech Republic
| | - Roar Kristoffersen
- Department of Arctic and Marine Biology, Faculty of Biosciences, Fisheries and Economics, UiT The Arctic University of Norway, N9037 Tromsø, Norway; (R.K.); (R.K.)
| | - Rune Knudsen
- Department of Arctic and Marine Biology, Faculty of Biosciences, Fisheries and Economics, UiT The Arctic University of Norway, N9037 Tromsø, Norway; (R.K.); (R.K.)
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8
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Abundance and Annual Distribution of Freshwater Snails and Some Trematode Cercariae at Damietta Governorate, Egypt. Helminthologia 2021; 58:233-247. [PMID: 34934387 PMCID: PMC8647957 DOI: 10.2478/helm-2021-0026] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2020] [Accepted: 05/12/2021] [Indexed: 11/20/2022] Open
Abstract
In addition to being a good food source, freshwater snails are considered one of the positively and negatively influencing invertebrates on the environment. Several biotic and abiotic factors are thought to affect the distribution and the dynamics of these snails. Freshwater snails are the most dominant and conspicuous individuals of the freshwater biota in Damietta Governorate. In this study, freshwater snails were collected monthly from 5 geographically and environmentally different sites at Damietta Governorate at the north of Egypt during June 2017-May 2018. Seven snail species; Lanistes carinatus, Lanistes varicus, Pila wernei, Segmentorbis angustus, Melanoides tuberculata, Biomphalaria alexandrina, and Gabbiella senoriansis, were identified. Lanistes carinatus was the most abundant species (56.4%) in the collection sites. Besides, Al-Inaniyyah village had the highest snail species abundance and variety. The abundance of the most recorded species varied seasonally; the highest abundance was recorded during summer while the lowest was during winter. The abundance of some snail species correlated positively or negatively with some physico-chemical parameters; water temperature, dissolved oxygen, conductivity, total dissolved salts, and electrical conductivity. Two types of trematode cercariae; gymnocephalus cercariae and xiphidiocercariae, were harvested from Lanistes carinatus. The highest prevalence of both cercarial types was detected during summer. The correlation between the prevalence of both cercarial types and the physico-chemical parameters were determined. Xiphidiocercariae were the most predominant cercarial type in Damietta Governorate. Our findings suggest that the invasion of some freshwater snails is likely to be the cause of the low prevalence or complete absence of some medically important intermediate snail hosts. We recommend further characterization of the distribution of freshwater snails and the interrelationships among them in Egypt, and suggest a controlled use of selected snail species to combat their medically important analogues.
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9
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Abstract
Some parasitoid wasps possess soldier castes during their parasitic larval stage, but are often neglected from our evolutionary theories explaining caste systems in animal societies. This is primarily due to the polyembryonic origin of their societies. However, recent discoveries of polyembryonic trematodes (i.e. flatworms) possessing soldier castes require us to reconsider this reasoning. I argue we can benefit from including these polyembryonic parasites in eusocial discussions, for polyembryony and parasitism are taxonomically vast and influence the evolution of social behaviours and caste systems in various circumstances. Despite their polyembryony, their social evolution can be explained by theories of eusociality designed for parent–offspring groups, which are the subjects of most social evolution research. Including polyembryonic parasites in these theories follows the trend of major evolutionary transitions theory expanding social evolution research into all levels of biological organization. In addition, these continued discoveries of caste systems in parasites suggest social evolution may be more relevant to parasitology than currently acknowledged.
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Affiliation(s)
- Brian A Whyte
- Department of Environmental Science, Policy and Management, University of California, Berkeley, CA, USA
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10
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Cost of interspecific competition between trematode colonies. J Helminthol 2020; 94:e139. [PMID: 32238196 DOI: 10.1017/s0022149x20000243] [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: 11/06/2022]
Abstract
In a range of trematode species, specific members of the parthenitae colony infecting the molluscan first intermediate host appear specialized for defence against co-infecting species. The evolution of such division of labour requires that co-infection entails fitness costs. Yet, this premise has very rarely been tested in species showing division of labour. Using Himasthla elongata (Himasthlidae) and Renicola roscovita (Renicolidae) infecting periwinkles Littorina littorea as study system, we show that the size of emerged cercariae is markedly reduced in both parasite species when competing over host resources. Cercarial longevity, on the other hand, is negatively influenced by competition only in R. roscovita. Season, which may impact the nutritional state of the host, also affects cercarial size, but only in H. elongata. Hence, our study underlines that cercarial quality is, indeed, compromised by competition, not only in the inferior R. roscovita (no division of labour) but also in the competitively superior H. elongata (division of labour).
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11
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Abstract
One of the most important aspects of the scientific endeavour is the definition of specific concepts as precisely as possible. However, it is also important not to lose sight of two facts: (i) we divide the study of nature into manageable parts in order to better understand it owing to our limited cognitive capacities and (ii) definitions are inherently arbitrary and heavily influenced by cultural norms, language, the current political climate, and even personal preferences, among many other factors. As a consequence of these facts, clear-cut definitions, despite their evident importance, are oftentimes quite difficult to formulate. One of the most illustrative examples about the difficulty of articulating precise scientific definitions is trying to define the concept of a brain. Even though the current thinking about the brain is beginning to take into account a variety of organisms, a vertebrocentric bias still tends to dominate the scientific discourse about this concept. Here I will briefly explore the evolution of our 'thoughts about the brain', highlighting the difficulty of constructing a universally (or even a generally) accepted formal definition of it and using planarians as one of the earliest examples of organisms proposed to possess a 'traditional', vertebrate-style brain. I also suggest that the time is right to attempt to expand our view of what a brain is, going beyond exclusively structural and taxa-specific criteria. Thus, I propose a classification that could represent a starting point in an effort to expand our current definitions of the brain, hopefully to help initiate conversations leading to changes of perspective on how we think about this concept. This article is part of the theme issue 'Liquid brains, solid brains: How distributed cognitive architectures process information'.
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Affiliation(s)
- Oné R Pagán
- Department of Biology, West Chester University , West Chester, PA 19383 , USA
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12
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Resetarits EJ, Torchin ME, Hechinger RF. Social trematode parasites increase standing army size in areas of greater invasion threat. Biol Lett 2020; 16:20190765. [PMID: 32097594 PMCID: PMC7058954 DOI: 10.1098/rsbl.2019.0765] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2019] [Accepted: 01/31/2020] [Indexed: 11/12/2022] Open
Abstract
Organisms or societies are resource limited, causing important trade-offs between reproduction and defence. Given such trade-offs, optimal allocation theory predicts that, for animal societies with a soldier caste, allocation to soldiers should reflect local external threats. Although both threat intensity and soldier allocation can vary widely in nature, we currently lack strong evidence that spatial variation in threat can drive the corresponding variation in soldier allocation. The diverse guild of trematode parasites of the California horn snail provides a useful system to address this problem. Several of these species form colonies in their hosts with a reproductive division of labour including a soldier caste. Soldiers are non-reproductive and specialized in defence, attacking and killing invading parasites. We quantified invasion threat and soldier allocation for 168 trematode colonies belonging to six species at 26 sites spread among 10 estuaries in temperate and tropical regions. Spatial variation in invasion threat was matched as predicted by the relative number of soldiers for multiple parasite species. Soldier allocation correlated with invasion threat at fine spatial scales, suggesting that allocation is at least partly inducible. These results may represent the first clear documentation of a spatial correlation between allocation to any type of caste and a biotic selective agent.
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Affiliation(s)
- Emlyn J. Resetarits
- Center for the Ecology of Infectious Disease, Odum School of Ecology, University of Georgia, Athens, GA, USA
- Department of Integrative Biology, University of Texas, Austin, TX, USA
- Smithsonian Tropical Research Institute, Balboa, Ancon, Republic of Panama
| | - Mark E. Torchin
- Smithsonian Tropical Research Institute, Balboa, Ancon, Republic of Panama
- Marine Science Institute, University of California, Santa Barbara, CA, USA
| | - Ryan F. Hechinger
- Scripps Institution of Oceanography, Marine Biology Research Division, University of California-San Diego, La Jolla, CA, USA
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13
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Laidemitt MR, Anderson LC, Wearing HJ, Mutuku MW, Mkoji GM, Loker ES. Antagonism between parasites within snail hosts impacts the transmission of human schistosomiasis. eLife 2019; 8:50095. [PMID: 31845890 PMCID: PMC6917487 DOI: 10.7554/elife.50095] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2019] [Accepted: 11/16/2019] [Indexed: 01/16/2023] Open
Abstract
Human disease agents exist within complex environments that have underappreciated effects on transmission, especially for parasites with multi-host life cycles. We examined the impact of multiple host and parasite species on transmission of the human parasite Schistosoma mansoni in Kenya. We show S. mansoni is impacted by cattle and wild vertebrates because of their role in supporting trematode parasites, the larvae of which have antagonistic interactions with S. mansoni in their shared Biomphalaria vector snails. We discovered the abundant cattle trematode, Calicophoron sukari, fails to develop in Biomphalaria pfeifferi unless S. mansoni larvae are present in the same snail. Further development of S. mansoni is subsequently prevented by C. sukari’s presence. Modeling indicated that removal of C. sukari would increase S. mansoni-infected snails by two-fold. Predictable exploitation of aquatic habitats by humans and their cattle enable C. sukari to exploit S. mansoni, thereby limiting transmission of this human pathogen.
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Affiliation(s)
- Martina R Laidemitt
- Department of Biology, University of New Mexico, Albuquerque, United States.,Center for Evolutionary and Theoretical Immunology (CETI), University of New Mexico, Albuquerque, United States
| | - Larissa C Anderson
- Department of Biology, University of New Mexico, Albuquerque, United States.,Center for Evolutionary and Theoretical Immunology (CETI), University of New Mexico, Albuquerque, United States
| | - Helen J Wearing
- Department of Biology, University of New Mexico, Albuquerque, United States.,Center for Evolutionary and Theoretical Immunology (CETI), University of New Mexico, Albuquerque, United States.,Department of Mathematics and Statistics, University of New Mexico, Albuquerque, United States
| | - Martin W Mutuku
- Centre for Biotechnology Research and Development, Kenya Medical Research Institute, Nairobi, Kenya
| | - Gerald M Mkoji
- Centre for Biotechnology Research and Development, Kenya Medical Research Institute, Nairobi, Kenya
| | - Eric S Loker
- Department of Biology, University of New Mexico, Albuquerque, United States.,Center for Evolutionary and Theoretical Immunology (CETI), University of New Mexico, Albuquerque, United States
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14
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Laidemitt MR, Brant SV, Mutuku MW, Mkoji GM, Loker ES. The diverse echinostomes from East Africa: With a focus on species that use Biomphalaria and Bulinus as intermediate hosts. Acta Trop 2019; 193:38-49. [PMID: 30710531 PMCID: PMC6461134 DOI: 10.1016/j.actatropica.2019.01.025] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2018] [Revised: 01/27/2019] [Accepted: 01/29/2019] [Indexed: 10/29/2022]
Abstract
Echinostomes are a diverse group of digenetic trematodes that are globally distributed. The diversity of echinostomes in Africa remains largely unknown, particularly in analyses using molecular markers. Therefore, we were interested in the composition and host usage patterns of African echinostomes, especially those that also use schistosome transmitting snails as intermediate hosts. We collected adults and larval stages of echinostomes from 19 different localities in East Africa (1 locality in Uganda and 18 in Kenya). In this study we provide locality information, host use, museum vouchers, and genetic data for two loci (28S and nad1) from 98 samples of echinostomes from East Africa. Combining morphological features, host use information, and phylogenetic analyses we found 17 clades of echinostomes in East Africa. Four clades were found to use more than one genus of freshwater snails as their first intermediate hosts. We also determined at least partial life cycles (2 of the 3) of four clades using molecular markers. Of the 17 clades, 13 use Biomphalaria or Bulinus as a first intermediate host. The overlap in host usage creates opportunities for competition, including against human schistosomes. Thus, our study can be used as a foundation for future studies to ascertain the interactions between schistosomes and echinostomes in their respective intermediate hosts.
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15
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Alda P, Bonel N, Cazzaniga NJ, Martorelli SR, Lafferty KD. A strong colonizer rules the trematode guild in an intertidal snail host. Ecology 2019; 100:e02696. [PMID: 30908617 DOI: 10.1002/ecy.2696] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/02/2018] [Revised: 02/04/2019] [Accepted: 02/25/2019] [Indexed: 11/08/2022]
Abstract
We examined the extent to which supply-side, niche, and competition theories and concepts help explain a trematode community in which one species comprises 87% of the trematode individuals, and the remaining 15 species each have <3%. We collected and dissected the common and wide-ranging snail host Heleobia australis over four seasons from three distinct habitats from the intertidal area of the Bahía Blanca estuary, Argentina. Inside a snail, trematodes interact with each other with outcomes that depend on facilitation, competition, and preemption, suggesting that dominant species should be common. The abundant trematode species, Microphallus simillimus, is a weak competitor, but has life-history traits and strategies associated with higher colonization ability that could increase its probability of invading the host first, allowing it to preempt the rare species. Rather than segregate by habitat, trematode species aggregated in pans during the summer where dominant trematode species often excluded subordinate ones. Despite losses to competition, and a lack of niche partitioning, M. simillimus ruled this species-rich trematode guild through strong recruitment and (potentially) preemption. Therefore, extremely skewed species abundance distributions, like this one, can derive from extremely skewed colonization abilities.
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Affiliation(s)
- Pilar Alda
- Laboratorio de Zoología de Invertebrados I, Departamento de Biología, Bioquímica y Farmacia, Universidad Nacional del Sur, San Juan 670, B8000ICN, Bahía Blanca, Argentina.,Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Godoy Cruz 2290, C1425FQB, Buenos Aires, Argentina
| | - Nicolás Bonel
- Laboratorio de Zoología de Invertebrados I, Departamento de Biología, Bioquímica y Farmacia, Universidad Nacional del Sur, San Juan 670, B8000ICN, Bahía Blanca, Argentina.,Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Godoy Cruz 2290, C1425FQB, Buenos Aires, Argentina.,Centre d'Ecologie Fonctionnelle et Evolutive, UMR 5175, CNRS, Université de Montpellier, Université Paul-Valéry Montpellier, Ecole Pratique des Hautes Etudes, 1919 Route de Mende, 34293, Montpellier Cedex 05, France
| | - Néstor J Cazzaniga
- Laboratorio de Zoología de Invertebrados I, Departamento de Biología, Bioquímica y Farmacia, Universidad Nacional del Sur, San Juan 670, B8000ICN, Bahía Blanca, Argentina
| | - Sergio R Martorelli
- Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Godoy Cruz 2290, C1425FQB, Buenos Aires, Argentina.,Centro de Estudios Parasitológicos y de Vectores (CONICET-UNLP), Avenida 120 s/n e/61 y 62, 1900, La Plata, Buenos Aires, Argentina
| | - Kevin D Lafferty
- Western Ecological Research Center, U.S. Geological Survey at Marine Science Institute, University of California, Santa Barbara, California, 93106, USA
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16
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Poulin R, Kamiya T, Lagrue C. Evolution, phylogenetic distribution and functional ecology of division of labour in trematodes. Parasit Vectors 2019; 12:5. [PMID: 30609937 PMCID: PMC6320615 DOI: 10.1186/s13071-018-3241-6] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2018] [Accepted: 11/28/2018] [Indexed: 11/13/2022] Open
Abstract
Division of labour has evolved in many social animals where colonies consist of clones or close kin. It involves the performance of different tasks by morphologically distinct castes, leading to increased colony fitness. Recently, a form of division of labour has been discovered in trematodes: clonal rediae inside the snail intermediate host belong either to a large-bodied reproductive caste, or to a much smaller and morphologically distinct ‘soldier’ caste which defends the colony against co-infecting trematodes. We review recent research on this phenomenon, focusing on its phylogenetic distribution, its possible evolutionary origins, and how division of labour functions to allow trematode colonies within their snail host to adjust to threats and changing conditions. To date, division of labour has been documented in 15 species from three families: Himasthlidae, Philophthalmidae and Heterophyidae. Although this list of species is certainly incomplete, the evidence suggests that division of labour has arisen independently more than once in the evolutionary history of trematodes. We propose a simple scenario for the gradual evolution of division of labour in trematodes facing a high risk of competition in a long-lived snail host. Starting with initial conditions prior to the origin of castes (size variation among rediae within a colony, size-dependent production of cercariae by rediae, and a trade-off between cercarial production and other functions, such as defence), maximising colony fitness (R0) can lead to caste formation or the age-structured division of labour observed in some trematodes. Finally, we summarise recent research showing that caste ratios, i.e. relative numbers of reproductive and soldier rediae per colony, become more soldier-biased in colonies exposed to competition from another trematode species sharing the same snail, and also respond to other stressors threatening the host’s survival or the colony itself. In addition, there is evidence of asymmetrical phenotypic plasticity among individual caste members: reproductives can assume defensive functions against competitors in the absence of soldiers, whereas soldiers are incapable of growing into reproductives if the latter’s numbers are reduced. We conclude by highlighting future research directions, and the advantages of trematodes as model systems to study social evolution.
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Affiliation(s)
- Robert Poulin
- Department of Zoology, University of Otago, Dunedin, New Zealand.
| | - Tsukushi Kamiya
- Department of Ecology and Evolutionary Biology, University of Toronto, Toronto, Canada
| | - Clément Lagrue
- Department of Biological Sciences, University of Alberta, Edmonton, Canada
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17
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Stewart Merrill TE, Cáceres CE. Within-host complexity of a plankton-parasite interaction. Ecology 2018; 99:2864-2867. [PMID: 30265378 DOI: 10.1002/ecy.2483] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/09/2018] [Revised: 07/13/2018] [Accepted: 07/20/2018] [Indexed: 11/06/2022]
Affiliation(s)
- Tara E Stewart Merrill
- Program in Ecology, Evolution and Conservation Biology, University of Illinois at Urbana-Champaign, Urbana, Illinois, 61801, USA
| | - Carla E Cáceres
- Program in Ecology, Evolution and Conservation Biology, University of Illinois at Urbana-Champaign, Urbana, Illinois, 61801, USA
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18
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Lagrue C, MacLeod CD, Keller L, Poulin R. Caste ratio adjustments in response to perceived and realised competition in parasites with division of labour. J Anim Ecol 2018; 87:1429-1439. [DOI: 10.1111/1365-2656.12873] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/25/2017] [Accepted: 05/19/2018] [Indexed: 11/27/2022]
Affiliation(s)
- Clément Lagrue
- Department of Zoology; University of Otago; Dunedin New Zealand
| | - Colin D. MacLeod
- Department of Zoology; University of British Columbia; Vancouver BC Canada
| | - Laurent Keller
- Department of Ecology and Evolution; University of Lausanne; Lausanne Switzerland
| | - Robert Poulin
- Department of Zoology; University of Otago; Dunedin New Zealand
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19
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Wittmann MJ, Fukami T. Eco-Evolutionary Buffering: Rapid Evolution Facilitates Regional Species Coexistence despite Local Priority Effects. Am Nat 2018; 191:E171-E184. [PMID: 29750553 DOI: 10.1086/697187] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
Inhibitory priority effects, in which early-arriving species exclude competing species from local communities, are thought to enhance regional species diversity via community divergence. Theory suggests, however, that these same priority effects make it difficult for species to coexist in the region unless individuals are continuously supplied from an external species pool, often an unrealistic assumption. Here we develop an eco-evolutionary hypothesis to solve this conundrum. We build a metacommunity model in which local priority effects occur between two species via interspecific interference. Within each species there are two genotypes: one is more resistant to interspecific interference than the other but pays a fitness cost for its resistance. Because of this trade-off, species evolve to become less resistant as they become regionally more common. Rare species can then invade some local patches and consequently recover in regional frequency. This "eco-evolutionary buffering" enables the regional coexistence of species despite local priority effects, even in the absence of immigration from an external species pool. Our model predicts that eco-evolutionary buffering is particularly effective when local communities are small and connected by infrequent dispersal.
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20
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MacLeod C, Poulin R, Lagrue C. Save your host, save yourself? Caste-ratio adjustment in a parasite with division of labor and snail host survival following shell damage. Ecol Evol 2018; 8:1615-1625. [PMID: 29435237 PMCID: PMC5792506 DOI: 10.1002/ece3.3782] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2017] [Revised: 11/27/2017] [Accepted: 12/06/2017] [Indexed: 11/11/2022] Open
Abstract
Shell damage and parasitic infections are frequent in gastropods, influencing key snail host life-history traits such as survival, growth, and reproduction. However, their interactions and potential effects on hosts and parasites have never been tested. Host-parasite interactions are particularly interesting in the context of the recently discovered division of labor in trematodes infecting marine snails. Some species have colonies consisting of two different castes present at varying ratios; reproductive members and nonreproductive soldiers specialized in defending the colony. We assessed snail host survival, growth, and shell regeneration in interaction with infections by two trematode species, Philophthalmus sp. and Maritrema novaezealandense, following damage to the shell in the New Zealand mud snail Zeacumantus subcarinatus. We concomitantly assessed caste-ratio adjustment between nonreproductive soldiers and reproductive members in colonies of the trematode Philophthalmus sp. in response to interspecific competition and shell damage to its snail host. Shell damage, but not parasitic infection, significantly increased snail mortality, likely due to secondary infections by pathogens. However, trematode infection and shell damage did not negatively affect shell regeneration or growth in Z. subcarinatus; infected snails actually produced more new shell than their uninfected counterparts. Both interspecific competition and shell damage to the snail host induced caste-ratio adjustment in Philophthalmus sp. colonies. The proportion of nonreproductive soldiers increased in response to interspecific competition and host shell damage, likely to defend the parasite colony and potentially the snail host against increasing threats. These results indicate that secondary infections by pathogens following shell damage to snails both significantly increased snail mortality and induced caste-ratio adjustments in parasites. This is the first evidence that parasites with a division of labor may be able to produce nonreproductive soldiers according to environmental factors other than interspecific competition with other parasites.
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Affiliation(s)
- Colin MacLeod
- Department of ZoologyUniversity of British ColumbiaVancouverBCCanada
| | - Robert Poulin
- Department of ZoologyUniversity of OtagoDunedinNew Zealand
| | - Clément Lagrue
- Department of ZoologyUniversity of OtagoDunedinNew Zealand
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21
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Sokolow SH, Wood CL, Jones IJ, Lafferty KD, Kuris AM, Hsieh MH, De Leo GA. To Reduce the Global Burden of Human Schistosomiasis, Use 'Old Fashioned' Snail Control. Trends Parasitol 2018; 34:23-40. [PMID: 29126819 PMCID: PMC5819334 DOI: 10.1016/j.pt.2017.10.002] [Citation(s) in RCA: 60] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2017] [Revised: 09/30/2017] [Accepted: 10/16/2017] [Indexed: 12/27/2022]
Abstract
Control strategies to reduce human schistosomiasis have evolved from 'snail picking' campaigns, a century ago, to modern wide-scale human treatment campaigns, or preventive chemotherapy. Unfortunately, despite the rise in preventive chemotherapy campaigns, just as many people suffer from schistosomiasis today as they did 50 years ago. Snail control can complement preventive chemotherapy by reducing the risk of transmission from snails to humans. Here, we present ideas for modernizing and scaling up snail control, including spatiotemporal targeting, environmental diagnostics, better molluscicides, new technologies (e.g., gene drive), and 'outside the box' strategies such as natural enemies, traps, and repellants. We conclude that, to achieve the World Health Assembly's stated goal to eliminate schistosomiasis, it is time to give snail control another look.
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Affiliation(s)
- Susanne H Sokolow
- Hopkins Marine Station, Stanford University, Pacific Grove, CA 93950, USA; Marine Science Institute, University of California, Santa Barbara, CA 93106, USA.
| | - Chelsea L Wood
- School of Aquatic and Fishery Sciences, University of Washington, Box 355020, Seattle, WA 98195-5020, USA
| | - Isabel J Jones
- Hopkins Marine Station, Stanford University, Pacific Grove, CA 93950, USA
| | - Kevin D Lafferty
- U.S. Geological Survey, Western Ecological Research Center, c/o Marine Science Institute, University of California, Santa Barbara, CA 93106, USA
| | - Armand M Kuris
- Marine Science Institute, University of California, Santa Barbara, CA 93106, USA
| | - Michael H Hsieh
- Children's National Health System, Washington DC, 20010, USA; The George Washington University, Washington DC, 20037, USA; Biomedical Research Institute, Rockville, MD 20850, USA
| | - Giulio A De Leo
- Hopkins Marine Station, Stanford University, Pacific Grove, CA 93950, USA
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22
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Worms at war: interspecific parasite competition and host resources alter trematode colony structure and fitness. Parasitology 2017; 144:1530-1542. [DOI: 10.1017/s003118201700107x] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
SUMMARYParasites competing over limited host resources are faced with a tradeoff between reproductive success and host overexploitation jeopardizing survival. Surprisingly little is known about the outcome of such competitive scenarios, and we therefore aimed at elucidating interactions between the trematodes Himasthla elongata and Renicola roscovita coinfecting the periwinkle first intermediate host. The results show that the success of Himasthla colonies (rediae) in terms of cercarial emission is unaffected by Renicola competition (sporocysts), whereas deteriating host condition decreases fitness. Furthermore, double infection has no bearing on Himasthla’s colony size but elevated the proportion of non-reproductive rediae that play a decisive role in colony defence. Opposite, the development of the Renicola colony (size/maturity), and in turn fitness, is markedly reduced in presence of Himasthla, whereas the nutritional state of the host appears less important. Hence, the intramolluscan competition between Himasthla and Renicola is asymmetrical, Himasthla being the superior competitor. Himasthla not only adjusts its virulence according to the hosts immediate nutritional state, it also nullifies the negative impact of a heterospecific competitor on own fitness. The latter is argued to follow in part from direct predation on the competitor, for which purpose more defensive non-reproductive rediae are strategically produced.
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23
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Boomsma JJ, Gawne R. Superorganismality and caste differentiation as points of no return: how the major evolutionary transitions were lost in translation. Biol Rev Camb Philos Soc 2017; 93:28-54. [PMID: 28508537 DOI: 10.1111/brv.12330] [Citation(s) in RCA: 122] [Impact Index Per Article: 17.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2016] [Revised: 03/04/2017] [Accepted: 03/08/2017] [Indexed: 12/27/2022]
Abstract
More than a century ago, William Morton Wheeler proposed that social insect colonies can be regarded as superorganisms when they have morphologically differentiated reproductive and nursing castes that are analogous to the metazoan germ-line and soma. Following the rise of sociobiology in the 1970s, Wheeler's insights were largely neglected, and we were left with multiple new superorganism concepts that are mutually inconsistent and uninformative on how superorganismality originated. These difficulties can be traced to the broadened sociobiological concept of eusociality, which denies that physical queen-worker caste differentiation is a universal hallmark of superorganismal colonies. Unlike early evolutionary naturalists and geneticists such as Weismann, Huxley, Fisher and Haldane, who set out to explain the acquisition of an unmated worker caste, the goal of sociobiology was to understand the evolution of eusociality, a broad-brush convenience category that covers most forms of cooperative breeding. By lumping a diverse spectrum of social systems into a single category, and drawing attention away from the evolution of distinct quantifiable traits, the sociobiological tradition has impeded straightforward connections between inclusive fitness theory and the major evolutionary transitions paradigm for understanding irreversible shifts to higher organizational complexity. We evaluate the history by which these inconsistencies accumulated, develop a common-cause approach for understanding the origins of all major transitions in eukaryote hierarchical complexity, and use Hamilton's rule to argue that they are directly comparable. We show that only Wheeler's original definition of superorganismality can be unambiguously linked to irreversible evolutionary transitions from context-dependent reproductive altruism to unconditional differentiation of permanently unmated castes in the ants, corbiculate bees, vespine wasps and higher termites. We argue that strictly monogamous parents were a necessary, albeit not sufficient condition for all transitions to superorganismality, analogous to single-zygote bottlenecking being a necessary but not sufficient condition for the convergent origins of complex soma across multicellular eukaryotes. We infer that conflict reduction was not a necessary condition for the origin of any of these major transitions, and conclude that controversies over the status of inclusive fitness theory primarily emanate from the arbitrarily defined sociobiological concepts of superorganismality and eusociality, not from the theory itself.
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Affiliation(s)
- Jacobus J Boomsma
- Centre for Social Evolution, Department of Biology, University of Copenhagen, Universitetsparken 15, 2100, Copenhagen, Denmark.,Department of Zoology, University of Oxford, South Parks Road, Oxford, OX1 3PS, UK
| | - Richard Gawne
- Centre for Social Evolution, Department of Biology, University of Copenhagen, Universitetsparken 15, 2100, Copenhagen, Denmark.,Department of Biology, Duke University, 130 Science Drive, Durham, NC, 27708, USA
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24
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Garcia-Vedrenne AE, Quintana ACE, DeRogatis AM, Dover CM, Lopez M, Kuris AM, Hechinger RF. Trematodes with a reproductive division of labour: heterophyids also have a soldier caste and early infections reveal how colonies become structured. Int J Parasitol 2016; 47:41-50. [PMID: 27914977 DOI: 10.1016/j.ijpara.2016.10.003] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2016] [Revised: 10/07/2016] [Accepted: 10/07/2016] [Indexed: 12/01/2022]
Abstract
Recent findings have extended the documentation of complex sociality to the Platyhelminthes, describing the existence of a reproductive division of labour involving a soldier caste among the parthenitae of trematode parasites. However, all species examined to date occupy high positions in trematode interspecific dominance hierarchies and belong to two closely related families, the Echinostomatidae and the Philophthalmidae (Superfamily Echinostomatoidea). Further, the two species documented as lacking soldiers also belong to the Echinostomatidae. Here, we examine four species of intermediate dominance, all belonging to the family Heterophyidae (Superfamily Opisthorchioidea): Euhaplorchis californiensis, Phocitremoides ovale, Pygidiopsoides spindalis and Stictodora hancocki, all of which infect the California horn snail, Cerithideopsis californica (=Cerithidea californica). We quantify morphology, distribution and behaviour of rediae from fully developed colonies. We also provide information on colony structure for three developing heterophyid colonies to better understand colony development. We discuss the implications of our findings, particularly with respect to how they suggest alternatives to the conclusions of other researchers concerning the nature of trematode sociality. Our analyses of morphological, distributional and behavioural patterns of developed colonies indicate that these heterophyid trematodes have a non-reproductive caste whose function is defence of the colony from invading trematodes. Hence, a soldier caste occurs for species lower in dominance hierarchies than previously known, and is present in at least two superfamilies of digenean trematodes, suggesting that selection for a soldier caste may be much more common among the Trematoda than previously recognised.
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Affiliation(s)
- Ana E Garcia-Vedrenne
- Department of Ecology, Evolution and Marine Biology, University of California, Santa Barbara, CA 93106, USA.
| | - Anastasia C E Quintana
- College of Creative Studies, University of California, Santa Barbara, CA 93106, USA; Department of Marine Science and Conservation, Nicholas School of the Environment, Duke University, Durham, NC 27708, USA
| | - Andrea M DeRogatis
- College of Creative Studies, University of California, Santa Barbara, CA 93106, USA; Department of Animal Science, University of California, Davis, CA 95616, USA
| | - Christina M Dover
- Department of Ecology, Evolution and Marine Biology, University of California, Santa Barbara, CA 93106, USA; Virginia-Maryland College of Veterinary Medicine, Blacksburg, VA 24061, USA
| | - Maribel Lopez
- Department of Ecology, Evolution and Marine Biology, University of California, Santa Barbara, CA 93106, USA
| | - Armand M Kuris
- Department of Ecology, Evolution and Marine Biology, University of California, Santa Barbara, CA 93106, USA; College of Creative Studies, University of California, Santa Barbara, CA 93106, USA
| | - Ryan F Hechinger
- Department of Ecology, Evolution and Marine Biology, University of California, Santa Barbara, CA 93106, USA; Scripps Institution of Oceanography, Marine Biology Research Division, University of California, San Diego, La Jolla, CA 92093, USA
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25
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Abstract
Paramphistomoids are ubiquitous and widespread digeneans that infect a diverse range of
definitive hosts, being particularly speciose in ruminants. We collected adult worms from
cattle, goats and sheep from slaughterhouses, and cercariae from freshwater snails from
ten localities in Central and West Kenya. We sequenced cox1 (690 bp) and
internal transcribed region 2 (ITS2) (385 bp) genes from a small piece of 79 different
adult worms and stained and mounted the remaining worm bodies for comparisons with
available descriptions. We also sequenced cox1 and ITS2 from 41
cercariae/rediae samples collected from four different genera of planorbid snails.
Combining morphological observations, host use information, genetic distance values and
phylogenetic methods, we delineated 16 distinct clades of paramphistomoids. For four of
the 16 clades, sequences from adult worms and cercariae/rediae matched, providing an
independent assessment for their life cycles. Much work is yet to be done to resolve fully
the relationships among paramphistomoids, but some correspondence between sequence- and
anatomically based classifications were noted. Paramphistomoids of domestic ruminants
provide one of the most abundant sources of parasitic flatworm biomass, and because of the
predilection of several species use Bulinus and
Biomphalaria snail hosts, have interesting linkages with the biology of
animal and human schistosomes to in Africa.
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26
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Mordecai EA, Jaramillo AG, Ashford JE, Hechinger RF, Lafferty KD. The role of competition - colonization tradeoffs and spatial heterogeneity in promoting trematode coexistence. Ecology 2016; 97:1484-1496. [DOI: 10.1890/15-0753.1] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/01/2015] [Revised: 11/20/2015] [Accepted: 12/07/2015] [Indexed: 12/18/2022]
Affiliation(s)
- Erin A. Mordecai
- Department of Biology; Stanford University; Stanford California 94305 USA
| | - Alejandra G. Jaramillo
- Ecology, Evolution, and Marine Biology; University of California; Santa Barbara California USA
| | - Jacob E. Ashford
- Environmental Sciences Department, Geology 2258, 900; University Ave; Riverside California USA
| | - Ryan F. Hechinger
- Marine Biology Research Division; Scripps Institution of Oceanography; University of California; San Diego California 92093 USA
| | - Kevin D. Lafferty
- US Geological Survey; Western Ecological Research Center; c/o Marine Science Institute; University of California; Santa Barbara California 93106 USA
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27
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Almeida CS, Cristaldo PF, Florencio DF, Cruz NG, Santos AA, Oliveira AP, Santana AS, Ribeiro EJ, Lima AP, Bacci L, Araújo AP. Combined foraging strategies and soldier behaviour in Nasutitermes aff. coxipoensis (Blattodea: Termitoidea: Termitidae). Behav Processes 2016; 126:76-81. [DOI: 10.1016/j.beproc.2016.03.006] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2015] [Revised: 03/09/2016] [Accepted: 03/11/2016] [Indexed: 10/22/2022]
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28
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29
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Powell S. A comparative perspective on the ecology of morphological diversification in complex societies: nesting ecology and soldier evolution in the turtle ants. Behav Ecol Sociobiol 2016. [DOI: 10.1007/s00265-016-2080-8] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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30
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Rautiala P, Gardner A. Intragenomic Conflict over Soldier Allocation in Polyembryonic Parasitoid Wasps. Am Nat 2016; 187:E106-15. [PMID: 27028082 DOI: 10.1086/685082] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
Understanding the selection pressures that have driven the evolution of sterile insect castes has been the focus of decades of intense scientific debate. An amenable empirical test bed for theory on this topic is provided by the sterile-soldier caste of polyembryonic parasitoid wasps. The function of these soldiers has been a source of controversy, with two basic hypotheses emerging: the "brood-benefit" hypothesis that they provide an overall benefit for their siblings and the "sex-ratio-conflict" hypothesis that the soldiers mediate a conflict between brothers and sisters by killing their opposite-sex siblings. Here, we investigate the divergent sex-ratio optima of a female embryo's maternal-origin and paternal-origin genes, to determine the potential for, and direction of, intragenomic conflict over soldiering. We then derive contrasting empirically testable predictions concerning the patterns of genomic imprinting that are expected to arise out of this intragenomic conflict, for the brood-benefit versus the sex-ratio-conflict hypothesis of soldier function.
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31
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Galaktionov KV, Podvyaznaya IM, Nikolaev KE, Levakin IA. Self-sustaining infrapopulation or colony? Redial clonal groups of Himasthla elongata (Mehlis, 1831) (Trematoda: Echinostomatidae) in Littorina littorea (Linnaeus) (Gastropoda: Littorinidae) do not support the concept of eusocial colonies in trematodes. Folia Parasitol (Praha) 2015; 62. [DOI: 10.14411/fp.2015.067] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2015] [Accepted: 09/29/2015] [Indexed: 11/19/2022]
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32
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Garcia-Vedrenne AE, Quintana ACE, DeRogatis AM, Martyn K, Kuris AM, Hechinger RF. Social Organization in Parasitic Flatworms--Four Additional Echinostomoid Trematodes Have a Soldier Caste and One Does Not. J Parasitol 2015; 102:11-20. [PMID: 26560890 DOI: 10.1645/15-853] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Abstract
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 6 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 5 echinostomoid species, 4 of which infect the marine snail Cerithidea californica and 1 (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 4 species from C. californica have a permanent soldier caste while E. liei does not. The observed intra- and inter-specific 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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Affiliation(s)
- Ana E Garcia-Vedrenne
- Department of Ecology, Evolution and Marine Biology and Marine Science Institute, University of California, Santa Barbara, California 93106
| | - Anastasia C E Quintana
- Department of Ecology, Evolution and Marine Biology and Marine Science Institute, University of California, Santa Barbara, California 93106
| | - Andrea M DeRogatis
- Department of Ecology, Evolution and Marine Biology and Marine Science Institute, University of California, Santa Barbara, California 93106
| | - Kayla Martyn
- Department of Ecology, Evolution and Marine Biology and Marine Science Institute, University of California, Santa Barbara, California 93106
| | - Armand M Kuris
- Department of Ecology, Evolution and Marine Biology and Marine Science Institute, University of California, Santa Barbara, California 93106
| | - Ryan F Hechinger
- Department of Ecology, Evolution and Marine Biology and Marine Science Institute, University of California, Santa Barbara, California 93106
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Relative reproductive success of co-infecting parasite genotypes under intensified within-host competition. INFECTION GENETICS AND EVOLUTION 2015; 36:450-455. [PMID: 26296607 DOI: 10.1016/j.meegid.2015.08.015] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/23/2015] [Revised: 08/06/2015] [Accepted: 08/12/2015] [Indexed: 12/24/2022]
Abstract
In nature, host individuals are commonly simultaneously infected with more than one genotype of the same parasite species. These co-infecting parasites often interact, which can affect their fitness and shape host-parasite ecology and evolution. Many of such interactions take place through competition for limited host resources. Therefore, variation in ecological factors modifying the host resource level could be important in determining the intensity of competition and the outcome of co-infections. We tested this hypothesis by measuring the relative reproductive success of co-infecting genotypes of the trematode parasite Diplostomum pseudospathaceum in its snail host Lymnaea stagnalis while experimentally manipulating snail resource level using contrasting feeding treatments (ad libitum food supply, no food). We found that food deprivation constrained the overall parasite within-host reproduction as the release of parasite transmission stages (cercariae) was reduced. This indicates intensified competition among the parasite genotypes. The genotypic composition of the released cercariae, however, was not affected by the feeding treatments. This suggests that in this system, the relative reproductive success of co-infecting parasite genotypes, which is an important component determining their fitness, is robust to variation in ecological factors modifying the strength of resource competition.
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Interference competition in entomopathogenic nematodes: male Steinernema kill members of their own and other species. Int J Parasitol 2014; 44:1009-17. [PMID: 25110292 DOI: 10.1016/j.ijpara.2014.07.004] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2014] [Revised: 07/01/2014] [Accepted: 07/04/2014] [Indexed: 11/21/2022]
Abstract
There is evidence of competition within and between helminth species, but the mechanisms involved are not well described. In interference competition, organisms prevent each other from using the contested resource through direct negative interactions, either chemical or physical. Steinernema spp. are entomopathogenic nematodes; they enter a living insect host which they kill and consume with the aid of symbiotic bacteria. Several studies have demonstrated intra- and interspecific competition in Steinernema, mediated by a scramble for resources and by incompatibility of the bacterial symbiont. Here we describe a mechanism by which male Steinernema may compete directly for resources, both food (host) and females, by physically injuring or killing members of another species as well as males of their own species. A series of experiments was conducted in hanging drops of insect haemolymph. Males of each of four species (Steinernemalongicaudum, Steinernemacarpocapsae, Steinernemakraussei and Steinernemafeltiae), representing three of the five phylogenetic clades of the genus, killed each other. Within 48h, up to 86% of pairs included at least one dead male, compared with negligible mortality in single male controls. There was evidence of intraspecific difference: one strain of S. feltiae (4CFMO) killed while another (UK76) did not. Males also killed both females and males of other Steinernema spp. There was evidence of a hierarchy of killing, with highest mortality due to S. longicaudum followed by S. carpocapsae, S. kraussei and S. feltiae. Wax moth larvae were co-infected with members of two Steinernema spp. to confirm that killing also takes place in the natural environment of an insect cadaver. When insects were co-infected with one infective juvenile of each species, S. longicaudum males killed both S. feltiae UK76 and Steinernema hermaphroditum. Wax moths co-infected with larger, equal numbers of S. longicaudum and S. feltiae UK76 produced mainly S. longicaudum progeny, as expected based on hanging drop experiments.
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Gorbushin AM, Borisova EA. Himasthla elongata: Implantation of rediae to the specific iteroparous long-living host, Littorina littorea, results in the immune rejection. FISH & SHELLFISH IMMUNOLOGY 2014; 39:432-438. [PMID: 24931625 DOI: 10.1016/j.fsi.2014.05.035] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/28/2014] [Revised: 05/19/2014] [Accepted: 05/30/2014] [Indexed: 06/03/2023]
Abstract
All semelparous short-lived gastropods studied so far for the experimental transplantation of trematode parthenitae, from one specific host to another, showed more or less successful acceptance of implanted parasites. We implanted echinostomatid rediae, Himasthla elongata, to the specific iteroparous long-living host, coenogastropod Littorina littorea. Using simple and low-invasive implantation techniques we have tested 680 snails injected with 75 redia microhemipopulations (MHP) harvested from naturally infected snails. Neither young nor mature rediae were able to survive in the recipient periwinkles in the course of 30 days post-implantation. A strong immune response from the host was already evident within the first week after implantation: initial inactivation of motile rediae with toxic humoral immune factors, following encapsulation of the implants and increased hemocyte counts. In contrast, rediae from the same MHPs showed perfect survival rates in primary in vitro axenic cultures. The failure of the transplantation experiments is explained in terms of the compatibility matching phenotype model. In the studied host-parasite combination all periwinkles are potentially susceptible and all rediae MHPs are potentially infective, however the probability of the compatible phenotypes matching is virtually low. Low investment in L. littorea annual reproduction would result in increased investment in self maintenance and immune mechanisms, causing the general resistance to the trematode infestation. Presumably, this resistance is relatively higher in long-lived iteroparous gastropods compare to semelparous short-lived mollusks such as pulmonates.
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Affiliation(s)
- Alexander M Gorbushin
- Institute of Evolutionary Physiology and Biochemistry of the Russian Academy of Sciences (IEPhB RAS), St-Petersburg, Russia.
| | - Elena A Borisova
- Institute of Evolutionary Physiology and Biochemistry of the Russian Academy of Sciences (IEPhB RAS), St-Petersburg, Russia
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36
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de Bekker C, Merrow M, Hughes DP. From behavior to mechanisms: an integrative approach to the manipulation by a parasitic fungus (Ophiocordyceps unilateralis s.l.) of its host ants (Camponotus spp.). Integr Comp Biol 2014; 54:166-76. [PMID: 24907198 DOI: 10.1093/icb/icu063] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Co-evolution of parasites and their hosts has led to certain parasites adaptively manipulating the behavior of their hosts. Although the number of examples from different taxa for this phenomenon is growing, the mechanisms underlying parasite-induced manipulation of hosts' behavior are still poorly understood. The development of laboratory infections integrating various disciplines within the life sciences is an important step in that direction. Here, we advocate for such an integrative approach using the parasitic fungi of the genus Ophiocordyceps that induce an adaptive biting behavior in Camponotus ants as an example. We emphasize the use of behavioral assays under controlled laboratory conditions, the importance of temporal aspects of the behavior (possibly involving the circadian clock), and the need to approach colonizing parasites as organizations with a division of labor.
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Affiliation(s)
- Charissa de Bekker
- *Department of Entomology and Biology, Center for Infectious Disease Dynamics, Pennsylvania State University, University Park, State College, PA 16802, USA; Institute of Medical Psychology, Faculty of Medicine, Ludwig Maximilians Universität München, 80336 Munich, Germany
| | - Martha Merrow
- *Department of Entomology and Biology, Center for Infectious Disease Dynamics, Pennsylvania State University, University Park, State College, PA 16802, USA; Institute of Medical Psychology, Faculty of Medicine, Ludwig Maximilians Universität München, 80336 Munich, Germany
| | - David P Hughes
- *Department of Entomology and Biology, Center for Infectious Disease Dynamics, Pennsylvania State University, University Park, State College, PA 16802, USA; Institute of Medical Psychology, Faculty of Medicine, Ludwig Maximilians Universität München, 80336 Munich, Germany
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Geographic variation in caste ratio of trematode colonies with a division of labour reflect local adaptation. Parasitol Res 2014; 113:2593-602. [DOI: 10.1007/s00436-014-3913-x] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2014] [Accepted: 04/09/2014] [Indexed: 10/25/2022]
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Tian L, Zhou X. The soldiers in societies: defense, regulation, and evolution. Int J Biol Sci 2014; 10:296-308. [PMID: 24644427 PMCID: PMC3957085 DOI: 10.7150/ijbs.6847] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2013] [Accepted: 01/02/2014] [Indexed: 11/24/2022] Open
Abstract
The presence of reproductively altruistic castes is one of the primary traits of the eusocial societies. Adaptation and regulation of the sterile caste, to a certain extent, drives the evolution of eusociality. Depending on adaptive functions of the first evolved sterile caste, eusocial societies can be categorized into the worker-first and soldier-first lineages, respectively. The former is marked by a worker caste as the first evolved altruistic caste, whose primary function is housekeeping, and the latter is highlighted by a sterile soldier caste as the first evolved altruistic caste, whose task is predominantly colony defense. The apparent functional differences between these two fundamentally important castes suggest worker-first and soldier-first eusociality are potentially driven by a suite of distinctively different factors. Current studies of eusocial evolution have been focused largely on the worker-first Hymenoptera, whereas understanding of soldier-first lineages including termites, eusocial aphids, gall-dwelling thrips, and snapping shrimp, is greatly lacking. In this review, we summarize the current state of knowledge on biology, morphology, adaptive functions, and caste regulation of the soldier caste. In addition, we discuss the biological, ecological and genetic factors that might contribute to the evolution of distinct caste systems within eusocial lineages.
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Affiliation(s)
| | - Xuguo Zhou
- Department of Entomology, University of Kentucky, Lexington, KY 40546-0091, USA
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39
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Affiliation(s)
- Eric S. Loker
- Center for Evolutionary and Theoretical Immunology, Parasitology Division – Museum of Southwestern Biology, Department of Biology, University of New Mexico, Albuquerque, New Mexico 87131
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Ross L, Gardner A, Hardy N, West SA. Ecology, not the genetics of sex determination, determines who helps in eusocial populations. Curr Biol 2013; 23:2383-7. [PMID: 24268409 DOI: 10.1016/j.cub.2013.10.013] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2013] [Revised: 08/15/2013] [Accepted: 10/04/2013] [Indexed: 01/02/2023]
Abstract
In eusocial species, the sex ratio of helpers varies from female only, in taxa such as the social Hymenoptera (ants, bees, and wasps) [1], to an unbiased mixture of males and females, as in most termites [2]. Hamilton suggested that this difference owes to the haplodiploid genetics of the Hymenoptera leading to females being relatively more related to their siblings [3]. However, it has been argued that Hamilton's hypothesis does not work [4-9] and that the sex of helpers could instead be explained by variation in the ecological factors that favor eusociality [10]. Here we test these two competing hypotheses, which focus on the possible importance of different terms in Hamilton's rule [2, 11], with a comparative study across all sexual eusocial taxa. We find that the sex ratio of helpers (1) shows no significant correlation with whether species are haplodiploid or diploid and (2) shows a strong correlation with the ecological factor that had favored eusociality. Specifically, when the role of helpers is to defend the nest, both males and females help, whereas when the role of helpers is to provide brood care, then helpers are the sex or sexes that provided parental care ancestrally. More generally, our results confirm the ability of kin selection theory to explain the biology of eusocial species, independently of ploidy, and add support to the idea that haplodiploidy has been more important for shaping conflicts within eusocial societies than for explaining its origins [6, 12-19].
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Affiliation(s)
- Laura Ross
- School of Biological Sciences, Institute of Evolutionary Biology, University of Edinburgh, Edinburgh, EH9 3JT, UK; Department of Zoology, University of Oxford, South Parks Road, Oxford OX1 3PS, UK.
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Multi-clone infections and the impact of intraspecific competition on trematode colonies with a division of labour. Parasitology 2013; 141:304-10. [PMID: 24148647 DOI: 10.1017/s0031182013001492] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
A division of labour occurs in colonies of the trematode Philophthalmus sp. within their first intermediate hosts. Two castes exist: one which reproduces and one which does not reproduce. It has been hypothesized that the benefit of the non-reproductive caste is in competitive interactions. Evidence for this from past experiments with Philophthalmus sp. colonies has been contradictory: the non-reproductive caste appears to benefit the colony in some way but not necessarily by combating interspecific competitors. The aims of this study were to consider intraspecific competition as a possible cause of the division of labour in Philophthalmus sp. colonies. Results show that mixed genotype infections occur in Philophthalmus sp. infected hosts and thus intraspecific competition is likely. Furthermore, the total number of individuals per colony is reduced in mixed genotype infections, indicating that intraspecific competition reduces colony fitness. However, the results do not indicate that the division of labour in Philophthalmus sp. plays a role in competitive interactions as the ratio of small, non-reproductive to large, reproductive individuals is unaffected by the presence of intraspecific competition. This is the first study to identify and quantify intraspecific competition in Philophthalmus sp., and to assess its selective role in this species' division of labour.
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42
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Lambden J, Johnson PTJ. Quantifying the biomass of parasites to understand their role in aquatic communities. Ecol Evol 2013; 3:2310-21. [PMID: 23919172 PMCID: PMC3728967 DOI: 10.1002/ece3.635] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2013] [Revised: 05/09/2013] [Accepted: 05/10/2013] [Indexed: 12/05/2022] Open
Abstract
By infecting multiple host species and acting as a food resource, parasites can affect food web topography and contribute to ecosystem energy transfer. Owing to the remarkable secondary production of some taxa, parasite biomass – although cryptic – can be comparable to other invertebrate and vertebrate groups. More resolved estimates of parasite biomass are therefore needed to understand parasite interactions, their consequences for host fitness, and potential influences on ecosystem energetics. We developed an approach to quantify the masses of helminth parasites and compared our results with those of biovolume-based approaches. Specifically, we massed larval and adult parasites representing 13 species and five life stages of trematodes and cestodes from snail and amphibian hosts. We used a replicated regression approach to quantify dry mass and compared these values with indirect biovolume estimates to test the validity of density assumptions. Our technique provided precise estimates (R2 from 0.69 to 0.98) of biomass across a wide range of parasite morphotypes and sizes. Individual parasites ranged in mass from 0.368 ± 0.041 to 320 ± 98.1 μg. Among trematodes, adult parasites tended to be the largest followed by rediae, with nonclonal larval stages (metacercariae and cercariae) as the smallest. Among similar morphotypes, direct estimates of dry mass and the traditional biovolume technique provided generally comparable estimates (although important exceptions also emerged). Finally, we present generalized length-mass regression equations to calculate trematode mass from length measurements, and discuss the most efficient use of limited numbers of parasites. By providing a novel method of directly estimating parasite biomass while also helping to validate more traditional methods involving length-mass conversion, our findings aim to facilitate future investigations into the ecological significance of parasites, particularly with respect to ecosystem energetics. In addition, this novel technique can be applied to a wide range of difficult-to-mass organisms.
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Affiliation(s)
- Jason Lambden
- Ecology and Evolutionary Biology, University of Colorado Ramaley N122, Boulder, Colorado, 80309-0334
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43
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Kamiya T, O’Dwyer K, Nuy J, Poulin R. What determines the growth of individual castes in social trematodes? Evol Ecol 2013. [DOI: 10.1007/s10682-013-9646-y] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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44
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Herrera EA. Ecological and genetic distribution of eusociality: the case for kin selection. Behav Ecol 2013. [DOI: 10.1093/beheco/ars166] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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45
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Reproduction and caste ratios under stress in trematode colonies with a division of labour. Parasitology 2013; 140:825-32. [DOI: 10.1017/s0031182012002235] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
SUMMARYTrematodes form clonal colonies in their first intermediate host. Individuals are, depending on species, rediae or sporocysts (which asexually reproduce) and cercariae (which develop within rediae or sporocysts and infect the next host). Some species use a division of labour within colonies, with 2 distinct redial morphs: small rediae (non-reproducing) and large rediae (individuals which produce cercariae). The theory of optimal caste ratio predicts that the ratio of caste members (small to large rediae) responds to environmental variability. This was tested in Philophthalmus sp. colonies exposed to host starvation and competition with the trematode, Maritrema novaezealandensis. Philophthalmus sp. infected snails, with and without M. novaezealandensis, were subjected to food treatments. Reproductive output, number of rediae, and the ratio of small to large rediae were compared among treatments. Philophthalmus sp. colonies responded to host starvation and competition; reproductive output was higher in well-fed snails of both infection types compared with snails in lower food treatments and well-fed, single infected snails compared with well-fed double infected snails. Furthermore, the caste ratio in Philophthalmus sp. colonies was altered in response to competition. This is the first study showing caste ratio responses to environmental pressures in trematodes with a division of labour.
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46
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Kamiya T, Poulin R. Behavioural plasticity of social trematodes depends upon social context. Biol Lett 2013; 9:20121027. [PMID: 23234865 DOI: 10.1098/rsbl.2012.1027] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Members of some social insects adjust their behaviours depending upon social context. Such plasticity allows colonies to sustain efficiency of the whole without the cost of additional production of individuals or delayed responses to perturbations. Using the recently discovered social clonal stage of trematode parasites, we investigated whether members of the reproductive caste adjust their defensive behaviour according to the local availability of non-reproductive defensive specialists, and if so whether the plasticity affects the short-term reproductive success of reproductive morphs. In vitro experiments demonstrated plasticity in competitive interactions of the reproductive morphs depending on the number of non-reproductive defensive specialists present nearby, which lead to differences in reproductive output at the individual level. This study provides support for the benefit of maintaining non-reproductive morphs in competitive situations, arising through socially mediated behavioural plasticity.
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Affiliation(s)
- T Kamiya
- Department of Zoology, University of Otago, Dunedin, New Zealand.
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47
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Louhi KR, Karvonen A, Rellstab C, Louhi R, Jokela J. Prevalence of infection as a predictor of multiple genotype infection frequency in parasites with multiple-host life cycle. J Anim Ecol 2012; 82:191-200. [DOI: 10.1111/j.1365-2656.2012.02028.x] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2012] [Accepted: 07/12/2012] [Indexed: 12/28/2022]
Affiliation(s)
- Katja-Riikka Louhi
- Department of Biological and Environmental Science; University of Jyväskylä; PO Box 35 FIN-40014 Jyväskylä Finland
- Department of Biological and Environmental Sciences; University of Helsinki; PO Box 65 FIN-00014 Helsinki Finland
| | - Anssi Karvonen
- Department of Biological and Environmental Science; University of Jyväskylä; PO Box 35 FIN-40014 Jyväskylä Finland
| | - Christian Rellstab
- Department of Biological and Environmental Science; University of Jyväskylä; PO Box 35 FIN-40014 Jyväskylä Finland
| | - Risto Louhi
- State Treasury/Insurance; Sörnäisten rantatie 13, PO Box 10 FIN-00054 Helsinki Finland
| | - Jukka Jokela
- Eawag, Swiss Federal Institute of Aquatic Science and Technology and ETH Zürich, Institution of Intergrative Biology (IBZ); Überlandstrasse 133, PO Box 611 CH-8600 Dübendorf Switzerland
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48
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Lloyd MM, Poulin R. Fitness benefits of a division of labour in parasitic trematode colonies with and without competition. Int J Parasitol 2012; 42:939-46. [PMID: 22935097 DOI: 10.1016/j.ijpara.2012.07.010] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2012] [Revised: 07/26/2012] [Accepted: 07/28/2012] [Indexed: 12/31/2022]
Abstract
A reproductive division of labour has recently been discovered within polyembryonic colonies of two species of parasitic trematodes infecting snail hosts. In these colonies, one morph expands the colony through asexual reproduction while the other morph never reproduces. As in other polyembryonic species using a division of labour (parasitoid wasps, one species of sea anemone), the non-reproducing morph appears specialized for defense against competing colonies. In this study, we first assessed competition between Philophthalmus sp. (which possesses reproducing and non-reproducing morphs) and the most common co-infecting species, Maritrema novaezealandensis, by quantifying colony success within snail hosts. Colonies of either species that did not compete within their host were more successful (i.e., produced more transmission stages) than colonies that were competing in a shared host. Second, we cultured individuals of both species in vitro, alone or together, to study the interaction more closely and to measure any advantage obtained by the colony from the non-reproducing morphs. This was done by manipulating the presence and abundance of M. novaezealandensis as well as the presence of the non-reproducing 'defensive' morph. Philophthalmus sp. colonies with both reproducing and non-reproducing morphs but without M. novaezealandensis were most successful. This implies the non-reproducing morphs provide a fitness benefit to Philophthalmus sp. colonies even in the absence of competition, although the nature of this advantage remains unclear.
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Affiliation(s)
- Melanie M Lloyd
- Department of Zoology, University of Otago, Dunedin 9054, New Zealand.
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49
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Rubenstein DR. Family feuds: social competition and sexual conflict in complex societies. Philos Trans R Soc Lond B Biol Sci 2012; 367:2304-13. [PMID: 22777018 PMCID: PMC3391424 DOI: 10.1098/rstb.2011.0283] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Darwin was initially puzzled by the processes that led to ornamentation in males-what he termed sexual selection-and those that led to extreme cooperation and altruism in complex animal societies-what was later termed kin selection. Here, I explore the relationships between sexual and kin selection theory by examining how social competition for reproductive opportunities-particularly in females-and sexual conflict over mating partners are inherent and critical parts of complex altruistic societies. I argue that (i) patterns of reproductive sharing within complex societies can drive levels of social competition and reproductive conflict not only in males but also in females living in social groups, and ultimately the evolution of female traits such as ornaments and armaments; (ii) mating conflict over female choice of sexual partners can influence kin structure within groups and drive the evolution of complex societies; and (iii) patterns of reproductive sharing and conflict among females may also drive the evolution of complex societies by influencing kin structure within groups. Ultimately, complex societies exhibiting altruistic behaviour appear to have only arisen in taxa where social competition over reproductive opportunities and sexual conflict over mating partners were low. Once such societies evolved, there were important selective feedbacks on traits used to regulate and mediate intra-sexual competition over reproductive opportunities, particularly in females.
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Affiliation(s)
- Dustin R Rubenstein
- Department of Ecology, Evolution and Environmental Biology, Columbia University, 10th Floor Schermerhorn Extension, 1200 Amsterdam Avenue, New York, NY 10027, USA.
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50
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Parasite diversity and coinfection determine pathogen infection success and host fitness. Proc Natl Acad Sci U S A 2012; 109:9006-11. [PMID: 22615371 DOI: 10.1073/pnas.1201790109] [Citation(s) in RCA: 123] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
While the importance of changes in host biodiversity for disease risk continues to gain empirical support, the influence of natural variation in parasite diversity on epidemiological outcomes remains largely overlooked. Here, we combined field infection data from 2,191 amphibian hosts representing 158 parasite assemblages with mechanistic experiments to evaluate the influence of parasite richness on both parasite transmission and host fitness. Using a guild of larval trematode parasites (six species) and an amphibian host, our experiments contrasted the effects of parasite richness vs. composition, observed vs. randomized assemblages, and additive vs. replacement designs. Consistent with the dilution effect hypothesis extended to intrahost diversity, increases in parasite richness reduced overall infection success, including infections by the most virulent parasite. However, the effects of parasite richness on host growth and survival were context dependent; pathology increased when parasites were administered additively, even when the presence of the most pathogenic species was held constant, but decreased when added species replaced or reduced virulent species, emphasizing the importance of community composition and assembly. These results were similar or stronger when community structures were weighted by their observed frequencies in nature. The field data also revealed the highly nested structure of parasite assemblages, with virulent species generally occupying basal positions, suggesting that increases in parasite richness and antagonism in nature will decrease virulent infections. Our findings emphasize the importance of parasite biodiversity and coinfection in affecting epidemiological responses and highlight the value of integrating research on biodiversity and community ecology for understanding infectious diseases.
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