101
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Palmer-Young EC, Hogeboom A, Kaye AJ, Donnelly D, Andicoechea J, Connon SJ, Weston I, Skyrm K, Irwin RE, Adler LS. Context-dependent medicinal effects of anabasine and infection-dependent toxicity in bumble bees. PLoS One 2017; 12:e0183729. [PMID: 28832668 PMCID: PMC5568382 DOI: 10.1371/journal.pone.0183729] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2017] [Accepted: 08/09/2017] [Indexed: 11/18/2022] Open
Abstract
BACKGROUND Floral phytochemicals are ubiquitous in nature, and can function both as antimicrobials and as insecticides. Although many phytochemicals act as toxins and deterrents to consumers, the same chemicals may counteract disease and be preferred by infected individuals. The roles of nectar and pollen phytochemicals in pollinator ecology and conservation are complex, with evidence for both toxicity and medicinal effects against parasites. However, it remains unclear how consistent the effects of phytochemicals are across different parasite lineages and environmental conditions, and whether pollinators actively self-medicate with these compounds when infected. APPROACH Here, we test effects of the nectar alkaloid anabasine, found in Nicotiana, on infection intensity, dietary preference, and survival and performance of bumble bees (Bombus impatiens). We examined variation in the effects of anabasine on infection with different lineages of the intestinal parasite Crithidia under pollen-fed and pollen-starved conditions. RESULTS We found that anabasine did not reduce infection intensity in individual bees infected with any of four Crithidia lineages that were tested in parallel, nor did anabasine reduce infection intensity in microcolonies of queenless workers. In addition, neither anabasine nor its isomer, nicotine, was preferred by infected bees in choice experiments, and infected bees consumed less anabasine than did uninfected bees under no-choice conditions. Furthermore, anabasine exacerbated the negative effects of infection on bee survival and microcolony performance. Anabasine reduced infection in only one experiment, in which bees were deprived of pollen and post-pupal contact with nestmates. In this experiment, anabasine had antiparasitic effects in bees from only two of four colonies, and infected bees exhibited reduced-rather than increased-phytochemical consumption relative to uninfected bees. CONCLUSIONS Variation in the effect of anabasine on infection suggests potential modulation of tritrophic interactions by both host genotype and environmental variables. Overall, our results demonstrate that Bombus impatiens prefer diets without nicotine and anabasine, and suggest that the medicinal effects and toxicity of anabasine may be context dependent. Future research should identify the specific environmental and genotypic factors that determine whether nectar phytochemicals have medicinal or deleterious effects on pollinators.
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Affiliation(s)
- Evan C. Palmer-Young
- Organismic & Evolutionary Biology, University of Massachusetts, Amherst, Massachusetts, United States of America
- Department of Biology, University of Massachusetts, Amherst, Massachusetts, United States of America
| | - Alison Hogeboom
- Department of Biology, University of Massachusetts, Amherst, Massachusetts, United States of America
| | - Alexander J. Kaye
- Department of Biology, Dartmouth College, Hanover, New Hampshire, United States of America
| | - Dash Donnelly
- Department of Biology, Dartmouth College, Hanover, New Hampshire, United States of America
| | - Jonathan Andicoechea
- Department of Biology, Dartmouth College, Hanover, New Hampshire, United States of America
| | - Sara June Connon
- Department of Biology, University of Massachusetts, Amherst, Massachusetts, United States of America
- Department of Applied Ecology, North Carolina State University, Raleigh, North Carolina, United States of America
| | - Ian Weston
- Department of Biology, University of Massachusetts, Amherst, Massachusetts, United States of America
| | - Kimberly Skyrm
- Department of Biology, University of Massachusetts, Amherst, Massachusetts, United States of America
| | - Rebecca E. Irwin
- Department of Biology, Dartmouth College, Hanover, New Hampshire, United States of America
- Department of Applied Ecology, North Carolina State University, Raleigh, North Carolina, United States of America
| | - Lynn S. Adler
- Department of Biology, University of Massachusetts, Amherst, Massachusetts, United States of America
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102
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Ecological and evolutionary approaches to managing honeybee disease. Nat Ecol Evol 2017; 1:1250-1262. [PMID: 29046562 PMCID: PMC5749923 DOI: 10.1038/s41559-017-0246-z] [Citation(s) in RCA: 39] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2017] [Accepted: 06/20/2017] [Indexed: 12/12/2022]
Abstract
Honeybee declines are a serious threat to global agricultural security and productivity. Although multiple factors contribute to these declines, parasites are a key driver. Disease problems in honeybees have intensified in recent years, despite increasing attention to addressing them. Here we argue that we must focus on the principles of disease ecology and evolution to understand disease dynamics, assess the severity of disease threats, and control these threats via honeybee management. We cover the ecological context of honeybee disease, including both host and parasite factors driving current transmission dynamics, and then discuss evolutionary dynamics including how beekeeping management practices may drive selection for more virulent parasites. We then outline how ecological and evolutionary principles can guide disease mitigation in honeybees, including several practical management suggestions for addressing short- and long-term disease dynamics and consequences. Multiple interacting factors have contributed to the rapid decline of honeybee populations worldwide. Here, the authors review the impact of parasites and pathogens, and how ecological and evolutionary principles can guide management practices.
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103
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Penley MJ, Ha GT, Morran LT. Evolution of Caenorhabditis elegans host defense under selection by the bacterial parasite Serratia marcescens. PLoS One 2017; 12:e0181913. [PMID: 28792961 PMCID: PMC5549931 DOI: 10.1371/journal.pone.0181913] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2016] [Accepted: 04/21/2017] [Indexed: 01/13/2023] Open
Abstract
Parasites can impose strong selection on hosts. In response, some host populations have adapted via the evolution of defenses that prevent or impede infection by parasites. However, host populations have also evolved life history shifts that maximize host fitness despite infection. Outcrossing and self-fertilization can have contrasting effects on evolutionary trajectories of host populations. While selfing and outcrossing are known to affect the rate at which host populations adapt in response to parasites, these mating systems may also influence the specific traits that underlie adaptation to parasites. Here, we determined the role of evolved host defense versus altered life history,in mixed mating (selfing and outcrossing) and obligately outcrossing C. elegans host populations after experimental evolution with the bacterial parasite, S. marcescens. Similar to previous studies, we found that both mixed mating and obligately outcrossing host populations adapted to S. marcescens exposure, and that the obligately outcrossing populations exhibited the greatest rates of adaptation. Regardless of the host population mating system, exposure to parasites did not significantly alter reproductive timing or total fecundity over the course of experimental evolution. However, both mixed mating and obligately outcrossing host populations exhibited significantly reduced mortality rates in the presence of the parasite after experimental evolution. Therefore, adaptation in both the mixed mating and obligately outcrossing populations was driven, at least in part, by the evolution of increased host defense and not changes in host life history. Thus, the host mating system altered the rate of adaptation, but not the nature of adaptive change in the host populations.
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Affiliation(s)
- McKenna J. Penley
- Department of Biology, Emory University, Atlanta, Georgia, United States of America
| | - Giang T. Ha
- Department of Biology, Emory University, Atlanta, Georgia, United States of America
| | - Levi T. Morran
- Department of Biology, Emory University, Atlanta, Georgia, United States of America
- * E-mail:
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104
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Elucidating the mechanisms underlying the beneficial health effects of dietary pollen on honey bees (Apis mellifera) infested by Varroa mite ectoparasites. Sci Rep 2017; 7:6258. [PMID: 28740210 PMCID: PMC5524784 DOI: 10.1038/s41598-017-06488-2] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2017] [Accepted: 06/13/2017] [Indexed: 12/16/2022] Open
Abstract
Parasites and pathogens of the honey bee (Apis mellifera) are key factors underlying colony losses, which are threatening the beekeeping industry and agriculture as a whole. To control the spread and development of pathogen infections within the colony, honey bees use plant resins with antibiotic activity, but little is known about the properties of other substances, that are mainly used as a foodstuff, for controlling possible diseases both at the individual and colony level. In this study, we tested the hypothesis that pollen is beneficial for honey bees challenged with the parasitic mite Varroa destructor associated to the Deformed Wing Virus. First, we studied the effects of pollen on the survival of infested bees, under laboratory and field conditions, and observed that a pollen rich diet can compensate the deleterious effects of mite parasitization. Subsequently, we characterized the pollen compounds responsible for the observed positive effects. Finally, based on the results of a transcriptomic analysis of parasitized bees fed with pollen or not, we developed a comprehensive framework for interpreting the observed effects of pollen on honey bee health, which incorporates the possible effects on cuticle integrity, energetic metabolism and immune response.
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105
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Lynch ZR, Schlenke TA, Morran LT, de Roode JC. Ethanol confers differential protection against generalist and specialist parasitoids of Drosophila melanogaster. PLoS One 2017; 12:e0180182. [PMID: 28700600 PMCID: PMC5507509 DOI: 10.1371/journal.pone.0180182] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2016] [Accepted: 06/12/2017] [Indexed: 12/20/2022] Open
Abstract
As parasites coevolve with their hosts, they can evolve counter-defenses that render host immune responses ineffective. These counter-defenses are more likely to evolve in specialist parasites than generalist parasites; the latter face variable selection pressures between the different hosts they infect. Natural populations of the fruit fly Drosophila melanogaster are commonly threatened by endoparasitoid wasps in the genus Leptopilina, including the specialist L. boulardi and the generalist L. heterotoma, and both wasp species can incapacitate the cellular immune response of D. melanogaster larvae. Given that ethanol tolerance is high in D. melanogaster and stronger in the specialist wasp than the generalist, we tested whether fly larvae could use ethanol as an anti-parasite defense and whether its effectiveness would differ against the two wasp species. We found that fly larvae benefited from eating ethanol-containing food during exposure to L. heterotoma; we observed a two-fold decrease in parasitization intensity and a 24-fold increase in fly survival to adulthood. Although host ethanol consumption did not affect L. boulardi parasitization rates or intensities, it led to a modest increase in fly survival. Thus, ethanol conferred stronger protection against the generalist wasp than the specialist. We tested whether fly larvae can self-medicate by seeking ethanol-containing food after being attacked by wasps, but found no support for this hypothesis. We also allowed female flies to choose between control and ethanol-containing oviposition sites in the presence vs. absence of wasps and generally found significant preferences for ethanol regardless of wasp presence. Overall, our results suggest that D. melanogaster larvae obtain protection from certain parasitoid wasp species through their mothers’ innate oviposition preferences for ethanol-containing food sources.
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Affiliation(s)
- Zachary R. Lynch
- Department of Biology, Emory University, Atlanta, Georgia, United States of America
- * E-mail:
| | - Todd A. Schlenke
- Department of Biology, Emory University, Atlanta, Georgia, United States of America
| | - Levi T. Morran
- Department of Biology, Emory University, Atlanta, Georgia, United States of America
| | - Jacobus C. de Roode
- Department of Biology, Emory University, Atlanta, Georgia, United States of America
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106
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Chan SY, Snow JW. Formidable challenges to the notion of biologically important roles for dietary small RNAs in ingesting mammals. GENES AND NUTRITION 2017; 12:13. [PMID: 29308096 PMCID: PMC5753850 DOI: 10.1186/s12263-017-0561-7] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/04/2017] [Accepted: 04/19/2017] [Indexed: 02/07/2023]
Abstract
The notion of uptake of active diet-derived small RNAs (sRNAs) in recipient organisms could have significant implications for our understanding of oral therapeutics and nutrition, for the safe use of RNA interference (RNAi) in agricultural biotechnology, and for ecological relationships. Yet, the transfer and subsequent regulation of gene activity by diet-derived sRNAs in ingesting mammals are still heavily debated. Here, we synthesize current information based on multiple independent studies of mammals, invertebrates, and plants. Rigorous assessment of these data emphasize that uptake of active dietary sRNAs is neither a robust nor a prevalent mechanism to maintain steady-state levels in higher organisms. While disagreement still continues regarding whether such transfer may occur in specialized contexts, concerns about technical difficulties and a lack of consensus on appropriate methods have led to questions regarding the reproducibility and biologic significance of some seemingly positive results. For any continuing investigations, concerted efforts should be made to establish a strong mechanistic basis for potential effects of dietary sRNAs and to agree on methodological guidelines for realizing such proof. Such processes would ensure proper interpretation of studies aiming to prove dietary sRNA activity in mammals and inform potential for application in therapeutics and agriculture.
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Affiliation(s)
- Stephen Y Chan
- Center for Pulmonary Vascular Biology and Medicine, Pittsburgh Heart, Lung, Blood, and Vascular Medicine Institute, Department of Medicine, University of Pittsburgh School of Medicine and University of Pittsburgh Medical Center, BST 1704.2, 200 Lothrop Street, Pittsburgh, PA 15261 USA
| | - Jonathan W Snow
- Department of Biology, Barnard College, New York, NY 10027 USA
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107
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Koch H, Brown MJ, Stevenson PC. The role of disease in bee foraging ecology. CURRENT OPINION IN INSECT SCIENCE 2017; 21:60-67. [PMID: 28822490 DOI: 10.1016/j.cois.2017.05.008] [Citation(s) in RCA: 47] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/16/2016] [Revised: 05/03/2017] [Accepted: 05/10/2017] [Indexed: 06/07/2023]
Abstract
Diseases have important but understudied effects on bee foraging ecology. Bees transmit and contract diseases on flowers, but floral traits including plant volatiles and inflorescence architecture may affect transmission. Diseases spill over from managed or invasive pollinators to native wild bee species, and impacts of emerging diseases are of particular concern, threatening pollinator populations and pollination services. Here we review how parasites can alter the foraging behaviour of bees by changing floral preferences and impairing foraging efficiency. We also consider how changes to pollinator behaviours alter or reduce pollination services. The availability of diverse floral resources can, however, ameliorate bee diseases and their impacts through better nutrition and antimicrobial effects of plant compounds in pollen and nectar.
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Affiliation(s)
| | - Mark Jf Brown
- School of Biological Sciences, Royal Holloway University of London, Egham, Surrey, UK
| | - Philip C Stevenson
- Royal Botanic Gardens, Kew, Surrey, UK; Natural Resources Institute, University of Greenwich, Kent, UK
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108
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Thomas F, Rome S, Mery F, Dawson E, Montagne J, Biro PA, Beckmann C, Renaud F, Poulin R, Raymond M, Ujvari B. Changes in diet associated with cancer: An evolutionary perspective. Evol Appl 2017; 10:651-657. [PMID: 28717385 PMCID: PMC5511355 DOI: 10.1111/eva.12465] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2016] [Accepted: 02/02/2017] [Indexed: 12/15/2022] Open
Abstract
Changes in diet are frequently correlated with the occurrence and progression of malignant tumors (i.e., cancer) in both humans and other animals, but an integrated conceptual framework to interpret these changes still needs to be developed. Our aim is to provide a new perspective on dietary changes in tumor‐bearing individuals by adapting concepts from parasitology. Dietary changes may occur alongside tumor progression for several reasons: (i) as a pathological side effect with no adaptive value, (ii) as the result of self‐medication by the host to eradicate the tumor and/or to slow down its progression, (iii) as a result of host manipulation by the tumor that benefits its progression, and finally (iv) as a host tolerance strategy, to alleviate and repair damages caused by tumor progression. Surprisingly, this tolerance strategy can be beneficial for the host even if diet changes are beneficial to tumor progression, provided that cancer‐induced death occurs sufficiently late (i.e., when natural selection is weak). We argue that more data and a unifying evolutionary framework, especially during the early stages of tumorigenesis, are needed to understand the links between changes in diet and tumor progression. We argue that a focus on dietary changes accompanying tumor progression can offer novel preventive and therapeutic strategies against cancer.
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Affiliation(s)
- Frédéric Thomas
- CREEC/MIVEGEC UMR IRD/CNRS/UM 5290 Montpellier Cedex 5 France
| | - Sophie Rome
- CarMen (UMR INSERM 1060, INRA 1397, INSA) Faculté de Médecine Lyon-Sud Université de Lyon Oullins France
| | - Frédéric Mery
- Evolution, Génomes, Comportement and Ecologie CNRS, IRD Université Paris-Sud, Université Paris-Saclay Gif-sur-Yvette France
| | - Erika Dawson
- Evolution, Génomes, Comportement and Ecologie CNRS, IRD Université Paris-Sud, Université Paris-Saclay Gif-sur-Yvette France
| | - Jacques Montagne
- Institute for Integrative Biology of the Cell (I2BC) CNRS Université Paris-Sud, CEA, UMR 9198 Gif-sur-Yvette France
| | - Peter A Biro
- Centre for Integrative Ecology School of Life and Environmental Sciences Deakin University Waurn Ponds VIC Australia
| | - Christa Beckmann
- Centre for Integrative Ecology School of Life and Environmental Sciences Deakin University Waurn Ponds VIC Australia
| | - François Renaud
- CREEC/MIVEGEC UMR IRD/CNRS/UM 5290 Montpellier Cedex 5 France
| | - Robert Poulin
- Department of Zoology University of Otago Dunedin New Zealand
| | - Michel Raymond
- Institute of Evolutionary Sciences University of Montpellier Montpellier France
| | - Beata Ujvari
- Centre for Integrative Ecology School of Life and Environmental Sciences Deakin University Waurn Ponds VIC Australia
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109
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Shikano I. Evolutionary Ecology of Multitrophic Interactions between Plants, Insect Herbivores and Entomopathogens. J Chem Ecol 2017; 43:586-598. [DOI: 10.1007/s10886-017-0850-z] [Citation(s) in RCA: 44] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2017] [Revised: 05/06/2017] [Accepted: 05/15/2017] [Indexed: 02/07/2023]
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110
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Palmer-Young EC, Thursfield L. Pollen extracts and constituent sugars increase growth of a trypanosomatid parasite of bumble bees. PeerJ 2017; 5:e3297. [PMID: 28503378 PMCID: PMC5426351 DOI: 10.7717/peerj.3297] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2017] [Accepted: 04/11/2017] [Indexed: 12/20/2022] Open
Abstract
Phytochemicals produced by plants, including at flowers, function in protection against plant diseases, and have a long history of use against trypanosomatid infection. Floral nectar and pollen, the sole food sources for many species of insect pollinators, contain phytochemicals that have been shown to reduce trypanosomatid infection in bumble and honey bees when fed as isolated compounds. Nectar and pollen, however, consist of phytochemical mixtures, which can have greater antimicrobial activity than do single compounds. This study tested the hypothesis that pollen extracts would inhibit parasite growth. Extracts of six different pollens were tested for direct inhibitory activity against cell cultures of the bumble bee trypanosomatid gut parasite Crithidia bombi. Surprisingly, pollen extracts increased parasite growth rather than inhibiting it. Pollen extracts contained high concentrations of sugars, mainly the monosaccharides glucose and fructose. Experimental manipulations of growth media showed that supplemental monosaccharides (glucose and fructose) increased maximum cell density, while a common floral phytochemical (caffeic acid) with inhibitory activity against other trypanosomatids had only weak inhibitory effects on Crithidia bombi. These results indicate that, although pollen is essential for bees and other pollinators, pollen may promote growth of intestinal parasites that are uninhibited by pollen phytochemicals and, as a result, can benefit from the nutrients that pollen provides.
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Affiliation(s)
- Evan C. Palmer-Young
- Organismic and Evolutionary Biology, University of Massachusetts at Amherst, Amherst, MA, United States of America
| | - Lucy Thursfield
- Royal Botanic Gardens, Kew, Richmond, Surrey, United Kingdom
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111
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Chan SY, Snow JW. Uptake and impact of natural diet-derived small RNA in invertebrates: Implications for ecology and agriculture. RNA Biol 2017; 14:402-414. [PMID: 27763816 PMCID: PMC5411125 DOI: 10.1080/15476286.2016.1248329] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2016] [Revised: 10/05/2016] [Accepted: 10/10/2016] [Indexed: 02/08/2023] Open
Abstract
The putative transfer and gene regulatory activities of diet-derived small RNAs (sRNAs) in ingesting animals are still debated. The existence of natural uptake of diet-derived sRNA by invertebrate species could have significant implication for our understanding of ecological relationships and could synergize with efforts to use RNA interference (RNAi) technology in agriculture. Here, we synthesize information gathered from studies in invertebrates using natural or artificial dietary delivery of sRNA and from studies of sRNA in vertebrate animals and plants to review our current understanding of uptake and impact of natural diet-derived sRNA on invertebrates. Our understanding has been influenced and sometimes confounded by the diversity of invertebrates and ingested plants studied, our limited insights into how gene expression may be modulated by dietary sRNAs at the mechanistic level, and the paucity of studies focusing directly on natural uptake of sRNA. As such, we suggest 2 strategies to investigate this phenomenon more comprehensively and thus facilitate the realization of its potentially broad impact on ecology and agriculture in the future.
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Affiliation(s)
- Stephen Y. Chan
- Center for Pulmonary Vascular Biology and Medicine, Pittsburgh Heart, Lung, Blood, and Vascular Medicine Institute, Department of Medicine, University of Pittsburgh School of Medicine and University of Pittsburgh Medical Center, Pittsburgh, PA, USA
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112
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Soler JJ, Ruiz-Castellano C, Figuerola J, Martín-Vivaldi M, Martínez-de la Puente J, Ruiz-Rodríguez M, Tomás G. Telomere length and dynamics of spotless starling nestlings depend on nest-building materials used by parents. Anim Behav 2017. [DOI: 10.1016/j.anbehav.2017.01.018] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
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113
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Poyet M, Eslin P, Chabrerie O, Prud'homme SM, Desouhant E, Gibert P. The invasive pest Drosophila suzukii uses trans-generational medication to resist parasitoid attack. Sci Rep 2017; 7:43696. [PMID: 28287118 PMCID: PMC5347128 DOI: 10.1038/srep43696] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2016] [Accepted: 01/26/2017] [Indexed: 11/29/2022] Open
Abstract
Animal medication is a behavioral strategy to resist enemies based on the use of substances from the environment. While it has been observed in several animals, whether invasive species can use medication to resist new enemies during its expansion is unknown. Here, we show that the worldwide invasive pest Drosophila suzukii performs trans-generational prophylactic medication by adapting its oviposition behavior in the presence of enemies. We find that flies preferentially lay their eggs on media containing atropine – an entomotoxic alkaloid – in the presence of parasitoids. We further show that flies developing on atropine more efficiently resist parasitization by parasitoids. Finally, we find that developing in hosts reared on atropine strongly impacts the life-history traits of parasitoids. This protective behavior is reported for the first time in a pest and invasive species, and suggests that animal medication may be an important driver of population dynamics during invasions.
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Affiliation(s)
- M Poyet
- Univ. Lyon, Université Claude Bernard Lyon 1, CNRS, Laboratoire de Biométrie et Biologie Evolutive, F-69100, Villeurbanne, France.,Unité Ecologie et Dynamique des Systèmes Anthropisés (FRE-CNRS 3498), Université de Picardie Jules Verne, Amiens, France
| | - P Eslin
- Unité Ecologie et Dynamique des Systèmes Anthropisés (FRE-CNRS 3498), Université de Picardie Jules Verne, Amiens, France
| | - O Chabrerie
- Unité Ecologie et Dynamique des Systèmes Anthropisés (FRE-CNRS 3498), Université de Picardie Jules Verne, Amiens, France
| | - S M Prud'homme
- Unité Ecologie et Dynamique des Systèmes Anthropisés (FRE-CNRS 3498), Université de Picardie Jules Verne, Amiens, France
| | - E Desouhant
- Univ. Lyon, Université Claude Bernard Lyon 1, CNRS, Laboratoire de Biométrie et Biologie Evolutive, F-69100, Villeurbanne, France
| | - P Gibert
- Univ. Lyon, Université Claude Bernard Lyon 1, CNRS, Laboratoire de Biométrie et Biologie Evolutive, F-69100, Villeurbanne, France
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114
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Brütsch T, Jaffuel G, Vallat A, Turlings TCJ, Chapuisat M. Wood ants produce a potent antimicrobial agent by applying formic acid on tree-collected resin. Ecol Evol 2017; 7:2249-2254. [PMID: 28405288 PMCID: PMC5383563 DOI: 10.1002/ece3.2834] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2016] [Revised: 01/06/2017] [Accepted: 01/28/2017] [Indexed: 11/08/2022] Open
Abstract
Wood ants fight pathogens by incorporating tree resin with antimicrobial properties into their nests. They also produce large quantities of formic acid in their venom gland, which they readily spray to defend or disinfect their nest. Mixing chemicals to produce powerful antibiotics is common practice in human medicine, yet evidence for the use of such "defensive cocktails" by animals remains scant. Here, we test the hypothesis that wood ants enhance the antifungal activity of tree resin by treating it with formic acid. In a series of experiments, we document that (i) tree resin had much higher inhibitory activity against the common entomopathogenic fungus Metarhizium brunneum after having been in contact with ants, while no such effect was detected for other nest materials; (ii) wood ants applied significant amounts of endogenous formic and succinic acid on resin and other nest materials; and (iii) the application of synthetic formic acid greatly increased the antifungal activity of resin, but had no such effect when applied to inert glass material. Together, these results demonstrate that wood ants obtain an effective protection against a detrimental microorganism by mixing endogenous and plant-acquired chemical defenses. In conclusion, the ability to synergistically combine antimicrobial substances of diverse origins is not restricted to humans and may play an important role in insect societies.
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Affiliation(s)
- Timothée Brütsch
- Department of Ecology and Evolution University of Lausanne Biophore, UNIL-Sorge Lausanne Switzerland
| | - Geoffrey Jaffuel
- Department of Ecology and Evolution University of Lausanne Biophore, UNIL-Sorge Lausanne Switzerland; FARCE Institute of Biology University of Neuchâtel Neuchâtel Switzerland
| | - Armelle Vallat
- Institute of Chemistry NPAC University of Neuchâtel Neuchâtel Switzerland
| | - Ted C J Turlings
- FARCE Institute of Biology University of Neuchâtel Neuchâtel Switzerland
| | - Michel Chapuisat
- Department of Ecology and Evolution University of Lausanne Biophore, UNIL-Sorge Lausanne Switzerland
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115
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Palmer-Young EC, Sadd BM, Irwin RE, Adler LS. Synergistic effects of floral phytochemicals against a bumble bee parasite. Ecol Evol 2017; 7:1836-1849. [PMID: 28331591 PMCID: PMC5355193 DOI: 10.1002/ece3.2794] [Citation(s) in RCA: 42] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2016] [Revised: 01/02/2017] [Accepted: 01/14/2017] [Indexed: 12/24/2022] Open
Abstract
Floral landscapes comprise diverse phytochemical combinations. Individual phytochemicals in floral nectar and pollen can reduce infection in bees and directly inhibit trypanosome parasites. However, gut parasites of generalist pollinators, which consume nectar and pollen from many plant species, are exposed to phytochemical combinations. Interactions between phytochemicals could augment or decrease effects of single compounds on parasites. Using a matrix of 36 phytochemical treatment combinations, we assessed the combined effects of two floral phytochemicals, eugenol and thymol, against four strains of the bumblebee gut trypanosome Crithidia bombi. Eugenol and thymol had synergistic effects against C. bombi growth across seven independent experiments, showing that the phytochemical combination can disproportionately inhibit parasites. The strength of synergistic effects varied across strains and experiments. Thus, the antiparasitic effects of individual compounds will depend on both the presence of other phytochemicals and parasite strain identity. The presence of synergistic phytochemical combinations could augment the antiparasitic activity of individual compounds for pollinators in diverse floral landscapes.
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Affiliation(s)
| | - Ben M Sadd
- School of Biological Sciences Illinois State University Normal IL USA
| | - Rebecca E Irwin
- Department of Applied Ecology North Carolina State University Raleigh NC USA
| | - Lynn S Adler
- Department of Biology University of Massachusetts at Amherst Amherst MA USA
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116
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Schmid-Hempel P. Parasites and Their Social Hosts. Trends Parasitol 2017; 33:453-462. [PMID: 28169113 DOI: 10.1016/j.pt.2017.01.003] [Citation(s) in RCA: 47] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2016] [Revised: 01/04/2017] [Accepted: 01/05/2017] [Indexed: 11/16/2022]
Abstract
The study of parasitism in socially living organisms shows that social group size correlates with the risk of infection, but group structure - and thus differences in contact networks - is generally more important. Also, genetic makeup or environmental conditions have effects. 'Social immunity' focuses on defence against parasites that are particular to social living. Recently, the role of socially transmitted microbiota for defence has become a focus, too. But whether and how parasites adapt to social organisms - beyond adaptation to solitary hosts - is poorly understood. Genomic and proteomic methods, as well as network analysis, will be tools that hold promise for many unsolved questions, but to expand our concepts in the first place is a much needed agenda.
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Affiliation(s)
- Paul Schmid-Hempel
- ETH Zürich, Institute of Integrative Biology (IBZ), ETH-Zentrum CHN, Universitätsstrasse 16, CH-8092 Zürich, Switzerland.
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117
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Palmer‐Young EC, Sadd BM, Adler LS. Evolution of resistance to single and combined floral phytochemicals by a bumble bee parasite. J Evol Biol 2017; 30:300-312. [PMID: 27783434 PMCID: PMC5324628 DOI: 10.1111/jeb.13002] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2016] [Revised: 10/20/2016] [Accepted: 10/21/2016] [Indexed: 01/05/2023]
Abstract
Repeated exposure to inhibitory compounds can drive the evolution of resistance, which weakens chemical defence against antagonists. Floral phytochemicals in nectar and pollen have antimicrobial properties that can ameliorate infection in pollinators, but evolved resistance among parasites could diminish the medicinal efficacy of phytochemicals. However, multicompound blends, which occur in nectar and pollen, present simultaneous chemical challenges that may slow resistance evolution. We assessed evolution of resistance by the common bumble bee gut parasite Crithidia bombi to two floral phytochemicals, singly and combined, over 6 weeks (~100 generations) of chronic exposure. Resistance of C. bombi increased under single and combined phytochemical exposure, without any associated costs of reduced growth under phytochemical-free conditions. After 6 weeks' exposure, phytochemical concentrations that initially inhibited growth by > 50%, and exceeded concentrations in floral nectar, had minimal effects on evolved parasite lines. Unexpectedly, the phytochemical combination did not impede resistance evolution compared to single compounds. These results demonstrate that repeated phytochemical exposure, which could occur in homogeneous floral landscapes or with therapeutic phytochemical treatment of managed hives, can cause rapid evolution of resistance in pollinator parasites. We discuss possible explanations for submaximal phytochemical resistance in natural populations. Evolved resistance could diminish the antiparasitic value of phytochemical ingestion, weakening an important natural defence against infection.
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Affiliation(s)
| | - B. M. Sadd
- School of Biological SciencesIllinois State UniversityNormalILUSA
| | - L. S. Adler
- Department of BiologyUniversity of Massachusetts at AmherstAmherstMAUSA
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118
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van Niekerk G, Loos B, Nell T, Engelbrecht AM. Autophagy--A free meal in sickness-associated anorexia. Autophagy 2016; 12:727-34. [PMID: 27050464 DOI: 10.1080/15548627.2016.1147672] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
Abstract
Activation of the immune system is metabolically costly, yet a hallmark of an infection is a reduction in appetite with a subsequent reduction in metabolite provision. What is the functional value of decreasing nutrient intake when an infection imposes large demands on metabolic parameters? Here, we propose that sickness-associated anorexia (SAA) upregulates the ancient process of autophagy systemically, thereby profoundly controlling not only immune- but also nonimmune-competent cells. This allows an advanced impact on the resolution of an infection through direct pathogen killing, enhancement of epitope presentation and the contribution toward the clearance of noxious factors. By rendering a 'free meal,' autophagy is thus most fundamentally harnessed during an anorexic response in order to promote both host tolerance and resistance. These findings strongly suggest a reassessment of numerous SAA-related clinical applications and a re-evaluation of current efforts in patient care.
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Affiliation(s)
- Gustav van Niekerk
- a Department of Physiological Sciences , Stellenbosch University , Stellenbosch , South Africa
| | - Ben Loos
- b Department of Physiological Sciences , Faculty of Natural Sciences, Stellenbosch University , Stellenbosch , South Africa
| | - Theo Nell
- b Department of Physiological Sciences , Faculty of Natural Sciences, Stellenbosch University , Stellenbosch , South Africa
| | - Anna-Mart Engelbrecht
- b Department of Physiological Sciences , Faculty of Natural Sciences, Stellenbosch University , Stellenbosch , South Africa
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119
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Darwin's finches treat their feathers with a natural repellent. Sci Rep 2016; 6:34559. [PMID: 27721475 PMCID: PMC5056383 DOI: 10.1038/srep34559] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2016] [Accepted: 09/12/2016] [Indexed: 11/08/2022] Open
Abstract
Darwin's finches are highly innovative. Recently we recorded for the first time a behavioural innovation in Darwin's finches outside the foraging context: individuals of four species rubbed leaves of the endemic tree Psidium galapageium on their feathers. We hypothesised that this behaviour serves to repel ectoparasites and tested the repellency of P. galapageium leaf extracts against parasites that negatively affect the fitness of Darwin's finches, namely mosquitoes and the invasive hematophagous fly Philornis downsi. Mosquitoes transmit pathogens which have recently been introduced by humans and the larvae of the fly suck blood from nestlings and incubating females. Our experimental evidence demonstrates that P. galapageium leaf extracts repel both mosquitoes and adult P. downsi and also inhibit the growth of P. downsi larvae. It is therefore possible that finches use this plant to repel ectopoarasites.
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120
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Stevenson PC, Nicolson SW, Wright GA. Plant secondary metabolites in nectar: impacts on pollinators and ecological functions. Funct Ecol 2016. [DOI: 10.1111/1365-2435.12761] [Citation(s) in RCA: 165] [Impact Index Per Article: 20.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Philip C. Stevenson
- Royal Botanic Gardens, Kew SurreyTW9 3AB UK
- Natural Resources Institute University of Greenwich KentME4 4TB UK
| | - Susan W. Nicolson
- Department of Zoology & Entomology University of Pretoria Private Bag X20 Hatfield0028 South Africa
| | - Geraldine A. Wright
- Centre for Behaviour and Evolution Institute of Neuroscience Newcastle University Newcastle upon TyneNE1 7RU UK
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121
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Shikano I, Cory JS. Altered nutrient intake by baculovirus-challenged insects: Self-medication or compensatory feeding? J Invertebr Pathol 2016; 139:25-33. [DOI: 10.1016/j.jip.2016.07.005] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2016] [Revised: 07/06/2016] [Accepted: 07/09/2016] [Indexed: 10/21/2022]
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122
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Hien DFDS, Dabiré KR, Roche B, Diabaté A, Yerbanga RS, Cohuet A, Yameogo BK, Gouagna LC, Hopkins RJ, Ouedraogo GA, Simard F, Ouedraogo JB, Ignell R, Lefevre T. Plant-Mediated Effects on Mosquito Capacity to Transmit Human Malaria. PLoS Pathog 2016; 12:e1005773. [PMID: 27490374 PMCID: PMC4973987 DOI: 10.1371/journal.ppat.1005773] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2016] [Accepted: 06/27/2016] [Indexed: 01/25/2023] Open
Abstract
The ecological context in which mosquitoes and malaria parasites interact has received little attention, compared to the genetic and molecular aspects of malaria transmission. Plant nectar and fruits are important for the nutritional ecology of malaria vectors, but how the natural diversity of plant-derived sugar sources affects mosquito competence for malaria parasites is unclear. To test this, we infected Anopheles coluzzi, an important African malaria vector, with sympatric field isolates of Plasmodium falciparum, using direct membrane feeding assays. Through a series of experiments, we then examined the effects of sugar meals from Thevetia neriifolia and Barleria lupilina cuttings that included flowers, and fruit from Lannea microcarpa and Mangifera indica on parasite and mosquito traits that are key for determining the intensity of malaria transmission. We found that the source of plant sugar meal differentially affected infection prevalence and intensity, the development duration of the parasites, as well as the survival and fecundity of the vector. These effects are likely the result of complex interactions between toxic secondary metabolites and the nutritional quality of the plant sugar source, as well as of host resource availability and parasite growth. Using an epidemiological model, we show that plant sugar source can be a significant driver of malaria transmission dynamics, with some plant species exhibiting either transmission-reducing or -enhancing activities.
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Affiliation(s)
| | - Kounbobr R. Dabiré
- Institut de Recherche en Sciences de la Santé (IRSS), Bobo Dioulasso, Burkina Faso
| | - Benjamin Roche
- UMISCO lab (Unité de Modélisation Mathématique et Informatique des Systèmes Complexes), UMI IRD/UPMC 209, Bondy, France
| | - Abdoulaye Diabaté
- Institut de Recherche en Sciences de la Santé (IRSS), Bobo Dioulasso, Burkina Faso
| | | | - Anna Cohuet
- MIVEGEC lab (Maladies Infectieuses et Vecteurs: Ecologie, Génétique, Evolution et Contrôle), UMR Université Montpellier, CNRS 5290, IRD 224, 911 Av. Agropolis, Montpellier, France
| | - Bienvenue K. Yameogo
- Institut de Recherche en Sciences de la Santé (IRSS), Bobo Dioulasso, Burkina Faso
| | - Louis-Clément Gouagna
- MIVEGEC lab (Maladies Infectieuses et Vecteurs: Ecologie, Génétique, Evolution et Contrôle), UMR Université Montpellier, CNRS 5290, IRD 224, 911 Av. Agropolis, Montpellier, France
| | - Richard J. Hopkins
- University of Greenwich, Natural Resource Institute–Department of Agriculture Health and Environment, Chatham Maritime, Kent, United Kingdom
| | | | - Frédéric Simard
- MIVEGEC lab (Maladies Infectieuses et Vecteurs: Ecologie, Génétique, Evolution et Contrôle), UMR Université Montpellier, CNRS 5290, IRD 224, 911 Av. Agropolis, Montpellier, France
| | - Jean-Bosco Ouedraogo
- Institut de Recherche en Sciences de la Santé (IRSS), Bobo Dioulasso, Burkina Faso
| | - Rickard Ignell
- Unit of Chemical Ecology, Department of Plant Protection Biology, Swedish University of Agricultural Sciences, Alnarp, Sweden
| | - Thierry Lefevre
- Institut de Recherche en Sciences de la Santé (IRSS), Bobo Dioulasso, Burkina Faso
- MIVEGEC lab (Maladies Infectieuses et Vecteurs: Ecologie, Génétique, Evolution et Contrôle), UMR Université Montpellier, CNRS 5290, IRD 224, 911 Av. Agropolis, Montpellier, France
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123
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Poirier‑Poulin S. Les primates non humains sont-ils médecins ? Une analyse critique des études sur l’automédication et de ses mécanismes premiers. REVUE DE PRIMATOLOGIE 2016. [DOI: 10.4000/primatologie.2575] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
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124
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Tao L, Hoang KM, Hunter MD, de Roode JC. Fitness costs of animal medication: antiparasitic plant chemicals reduce fitness of monarch butterfly hosts. J Anim Ecol 2016; 85:1246-54. [PMID: 27286503 DOI: 10.1111/1365-2656.12558] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2015] [Accepted: 05/25/2016] [Indexed: 12/01/2022]
Abstract
The emerging field of ecological immunology demonstrates that allocation by hosts to immune defence against parasites is constrained by the costs of those defences. However, the costs of non-immunological defences, which are important alternatives to canonical immune systems, are less well characterized. Estimating such costs is essential for our understanding of the ecology and evolution of alternative host defence strategies. Many animals have evolved medication behaviours, whereby they use antiparasitic compounds from their environment to protect themselves or their kin from parasitism. Documenting the costs of medication behaviours is complicated by natural variation in the medicinal components of diets and their covariance with other dietary components, such as macronutrients. In the current study, we explore the costs of the usage of antiparasitic compounds in monarch butterflies (Danaus plexippus), using natural variation in concentrations of antiparasitic compounds among plants. Upon infection by their specialist protozoan parasite Ophryocystis elektroscirrha, monarch butterflies can selectively oviposit on milkweed with high foliar concentrations of cardenolides, secondary chemicals that reduce parasite growth. Here, we show that these antiparasitic cardenolides can also impose significant costs on both uninfected and infected butterflies. Among eight milkweed species that vary substantially in their foliar cardenolide concentration and composition, we observed the opposing effects of cardenolides on monarch fitness traits. While high foliar cardenolide concentrations increased the tolerance of monarch butterflies to infection, they reduced the survival rate of caterpillars to adulthood. Additionally, although non-polar cardenolide compounds decreased the spore load of infected butterflies, they also reduced the life span of uninfected butterflies, resulting in a hump-shaped curve between cardenolide non-polarity and the life span of infected butterflies. Overall, our results suggest that the use of antiparasitic compounds carries substantial costs, which could constrain host investment in medication behaviours.
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Affiliation(s)
- Leiling Tao
- Department of Biology, Emory University, 1510 Clifton Road, Atlanta, GA, 30322, USA
| | - Kevin M Hoang
- Department of Biology, Emory University, 1510 Clifton Road, Atlanta, GA, 30322, USA
| | - Mark D Hunter
- Department of Ecology and Evolutionary Biology, University of Michigan, 830 N University Avenue, Ann Arbor, MI, 48109, USA
| | - Jacobus C de Roode
- Department of Biology, Emory University, 1510 Clifton Road, Atlanta, GA, 30322, USA
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125
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van Niekerk G, Isaacs AW, Nell T, Engelbrecht AM. Sickness-Associated Anorexia: Mother Nature's Idea of Immunonutrition? Mediators Inflamm 2016; 2016:8071539. [PMID: 27445441 PMCID: PMC4942670 DOI: 10.1155/2016/8071539] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2016] [Revised: 06/13/2016] [Accepted: 06/14/2016] [Indexed: 02/06/2023] Open
Abstract
During an infection, expansion of immune cells, assembly of antibodies, and the induction of a febrile response collectively place continual metabolic strain on the host. These considerations also provide a rationale for nutritional support in critically ill patients. Yet, results from clinical and preclinical studies indicate that aggressive nutritional support does not always benefit patients and may occasionally be detrimental. Moreover, both vertebrates and invertebrates exhibit a decrease in appetite during an infection, indicating that such sickness-associated anorexia (SAA) is evolutionarily conserved. It also suggests that SAA performs a vital function during an infection. We review evidence signifying that SAA may present a mechanism by which autophagic flux is upregulated systemically. A decrease in serum amino acids during an infection promotes autophagy not only in immune cells, but also in nonimmune cells. Similarly, bile acids reabsorbed postprandially inhibit hepatic autophagy by binding to farnesoid X receptors, indicating that SAA may be an attempt to conserve autophagy. In addition, augmented autophagic responses may play a critical role in clearing pathogens (xenophagy), in the presentation of epitopes in nonprovisional antigen presenting cells and the removal of damaged proteins and organelles. Collectively, these observations suggest that some patients might benefit from permissive underfeeding.
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Affiliation(s)
- Gustav van Niekerk
- Department of Physiological Sciences, Private Bag X1, Matieland, Stellenbosch 7600, South Africa
| | - Ashwin W. Isaacs
- Department of Physiological Sciences, Private Bag X1, Matieland, Stellenbosch 7600, South Africa
| | - Theo Nell
- Department of Physiological Sciences, Private Bag X1, Matieland, Stellenbosch 7600, South Africa
| | - Anna-Mart Engelbrecht
- Department of Physiological Sciences, Private Bag X1, Matieland, Stellenbosch 7600, South Africa
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126
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Smilanich AM, Fincher RM, Dyer LA. Does plant apparency matter? Thirty years of data provide limited support but reveal clear patterns of the effects of plant chemistry on herbivores. THE NEW PHYTOLOGIST 2016; 210:1044-1057. [PMID: 26889654 DOI: 10.1111/nph.13875] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/20/2015] [Accepted: 12/23/2015] [Indexed: 06/05/2023]
Abstract
According to the plant-apparency hypothesis, apparent plants allocate resources to quantitative defenses that negatively affect generalist and specialist herbivores, while unapparent plants invest more in qualitative defenses that negatively affect nonadapted generalists. Although this hypothesis has provided a useful framework for understanding the evolution of plant chemical defense, there are many inconsistencies surrounding associated predictions, and it has been heavily criticized and deemed obsolete. We used a hierarchical Bayesian meta-analysis model to test whether defenses from apparent and unapparent plants differ in their effects on herbivores. We collected a total of 225 effect sizes from 158 published papers in which the effects of plant chemistry on herbivore performance were reported. As predicted by the plant-apparency hypothesis, we found a prevalence of quantitative defenses in woody plants and qualitative defenses in herbaceous plants. However, the detrimental impacts of qualitative defenses were more effective against specialists than generalists, and the effects of chemical defenses did not significantly differ between specialists and generalists for woody or herbaceous plants. A striking pattern that emerged from our data was a pervasiveness of beneficial effects of secondary metabolites on herbivore performance, especially generalists. This pattern provides evidence that herbivores are evolving effective counteradaptations to putative plant defenses.
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Affiliation(s)
- Angela M Smilanich
- Department of Biology, University of Nevada, 1664 N. Virginia St, Reno, NV, 89557, USA
| | - R Malia Fincher
- Department of Biology, Samford University, 800 Lakeshore Dr., Birmingham, AL, 35229, USA
| | - Lee A Dyer
- Department of Biology, University of Nevada, 1664 N. Virginia St, Reno, NV, 89557, USA
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127
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Nunn CL, Craft ME, Gillespie TR, Schaller M, Kappeler PM. The sociality-health-fitness nexus: synthesis, conclusions and future directions. Philos Trans R Soc Lond B Biol Sci 2016; 370:rstb.2014.0115. [PMID: 25870401 DOI: 10.1098/rstb.2014.0115] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
This theme issue has highlighted the links between sociality, health and fitness in a broad range of organisms, and with approaches that include field and captive studies of animals, comparative and meta-analyses, theoretical modelling and clinical and psychological studies of humans. In this concluding chapter, we synthesize the results of these diverse studies into some of the key concepts discussed in this issue, focusing on risks of infectious disease through social contact, the effects of competition in groups on susceptibility to disease, and the integration of sociality into research on life-history trade-offs. Interestingly, the studies in this issue both support pre-existing hypotheses, and in other ways challenge those hypotheses. We focus on unexpected results, including a lack of association between ectoparasites and fitness and weak results from a meta-analysis of the links between dominance rank and immune function, and place these results in a broader context. We also review relevant topics that were not covered fully in this theme issue, including self-medication and sickness behaviours, society-level defences against infectious disease, sexual selection, evolutionary medicine, implications for conservation biology and selective pressures on parasite traits. We conclude by identifying general open questions to stimulate and guide future research on the links between sociality, health and fitness.
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Affiliation(s)
- Charles L Nunn
- Department of Evolutionary Anthropology, Duke University, Box 90383, Durham, NC 27708, USA Duke Global Health Institute, Duke University, 310 Trent Drive, Durham, NC 27710, USA
| | - Meggan E Craft
- Department of Veterinary Population Medicine, University of Minnesota, St Paul, MN 55108, USA
| | - Thomas R Gillespie
- Department of Environmental Sciences and Program in Population Biology, Ecology and Evolution, Emory University, Atlanta, GA 30322, USA Department of Environmental Health, Rollins School of Public Health, Emory University, Atlanta, GA 30322, USA
| | - Mark Schaller
- Department of Psychology, University of British Columbia, 2136 West Mall, Vancouver, British Columbia, Canada V6T1Z4
| | - Peter M Kappeler
- Behavioral Ecology and Sociobiology Unit, German Primate Center, Göttingen, Germany Department of Sociobiology/Anthropology, University of Göttingen, Göttingen, Germany
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128
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Xiong M, Shao X, Long Y, Bu H, Zhang D, Wang D, Li S, Wang R, Yao M. Molecular analysis of vertebrates and plants in scats of leopard cats (Prionailurus bengalensis) in southwest China. J Mammal 2016. [DOI: 10.1093/jmammal/gyw061] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Abstract
Understanding the diets of carnivores is essential for resolving food web interactions and the population dynamics of both prey and predators and for designing effective strategies for species and ecosystem conservation. As effective predators, wild felids play important roles in various ecosystems, but relatively little is known about the dietary habits of many species, primarily owing to their elusive behavior. We used a DNA-based method to analyze the vertebrates and plants constituting the diet of leopard cats (Prionailurus bengalensis) in the temperate forests of the mountains of southwest China, a global biodiversity hotspot. DNA extracted from leopard cat scats was amplified with primers targeting either the vertebrate mitochondrial 12S rRNA gene (N = 25 scats) or the psbCL region of the chloroplast genome of vascular plants (N = 42 scats). The polymerase chain reaction products were sequenced and prey taxa were assigned based on sequence similarity. We identified a total of 16 taxa of vertebrate prey, with pikas (in 76% of the scats) and rodents (40%) predominating. Plant material belonging to 12 taxa was found in 76% of the samples, and the genus Solanum and subfamily Rosoideae were the most frequently detected plant taxa. The frequency of occurrence of identified plant taxa differed between the spring–summer and fall–winter months. Thus, the leopard cats in our study area have a diversified diet and are highly flexible in adapting their foraging behavior to the locally available prey. Our data suggest that preserving their natural prey base dominated by pikas and rodents may be vital for the subsistence of local populations. The high species resolution and detection sensitivity of the DNA-based method we used in this study make it a powerful and efficient tool for fine-scale analysis of complex diets.
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Affiliation(s)
- Mengyin Xiong
- School of Life Sciences, Peking University, R. 640, Beijing 100871, China
| | - Xinning Shao
- School of Life Sciences, Peking University, R. 640, Beijing 100871, China
| | - Ying Long
- School of Life Sciences, Peking University, R. 640, Beijing 100871, China
| | - Hongliang Bu
- School of Life Sciences, Peking University, R. 640, Beijing 100871, China
| | - Dan Zhang
- School of Life Sciences, Peking University, R. 640, Beijing 100871, China
| | - Dajun Wang
- School of Life Sciences, Peking University, R. 640, Beijing 100871, China
| | - Sheng Li
- School of Life Sciences, Peking University, R. 640, Beijing 100871, China
| | - Rongjiang Wang
- School of Life Sciences, Peking University, R. 640, Beijing 100871, China
| | - Meng Yao
- School of Life Sciences, Peking University, R. 640, Beijing 100871, China
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129
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Humphrey PT, Gloss AD, Alexandre NM, Villalobos MM, Fremgen MR, Groen SC, Meihls LN, Jander G, Whiteman NK. Aversion and attraction to harmful plant secondary compounds jointly shape the foraging ecology of a specialist herbivore. Ecol Evol 2016; 6:3256-68. [PMID: 27096082 PMCID: PMC4829532 DOI: 10.1002/ece3.2082] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2015] [Revised: 02/17/2016] [Accepted: 02/22/2016] [Indexed: 01/15/2023] Open
Abstract
Most herbivorous insect species are restricted to a narrow taxonomic range of host plant species. Herbivore species that feed on mustard plants and their relatives in the Brassicales have evolved highly efficient detoxification mechanisms that actually prevent toxic mustard oils from forming in the bodies of the animals. However, these mechanisms likely were not present during the initial stages of specialization on mustard plants ~100 million years ago. The herbivorous fly Scaptomyza nigrita (Drosophilidae) is a specialist on a single mustard species, bittercress (Cardamine cordifolia; Brassicaceae) and is in a fly lineage that evolved to feed on mustards only in the past 10–20 million years. In contrast to many mustard specialists, S. nigrita does not prevent formation of toxic breakdown products (mustard oils) arising from glucosinolates (GLS), the primary defensive compounds in mustard plants. Therefore, it is an appealing model for dissecting the early stages of host specialization. Because mustard oils actually form in the bodies of S. nigrita, we hypothesized that in lieu of a specialized detoxification mechanism, S. nigrita may mitigate exposure to high GLS levels within plant tissues using behavioral avoidance. Here, we report that jasmonic acid (JA) treatment increased GLS biosynthesis in bittercress, repelled adult female flies, and reduced larval growth. S. nigrita larval damage also induced foliar GLS, especially in apical leaves, which correspondingly displayed the least S. nigrita damage in controlled feeding trials and field surveys. Paradoxically, flies preferred to feed and oviposit on GLS‐producing Arabidopsis thaliana despite larvae performing worse in these plants versus non‐GLS‐producing mutants. GLS may be feeding cues for S. nigrita despite their deterrent and defensive properties, which underscores the diverse relationship a mustard specialist has with its host when lacking a specialized means of mustard oil detoxification.
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Affiliation(s)
- Parris T Humphrey
- Ecology and Evolutionary Biology University of Arizona Tucson Arizona 85721; Rocky Mountain Biological Laboratory Gothic Colorado 81224; Present address: Organismic and Evolutionary Biology Harvard University Cambridge Massachusetts 02138
| | - Andrew D Gloss
- Ecology and Evolutionary Biology University of Arizona Tucson Arizona 85721; Rocky Mountain Biological Laboratory Gothic Colorado 81224
| | - Nicolas M Alexandre
- Ecology and Evolutionary Biology University of Arizona Tucson Arizona 85721; Rocky Mountain Biological Laboratory Gothic Colorado 81224
| | - Martha M Villalobos
- Ecology and Evolutionary Biology University of Arizona Tucson Arizona 85721; Rocky Mountain Biological Laboratory Gothic Colorado 81224
| | | | - Simon C Groen
- Ecology and Evolutionary Biology University of Arizona Tucson Arizona 85721; Rocky Mountain Biological Laboratory Gothic Colorado 81224
| | - Lisa N Meihls
- Boyce Thompson Institute for Plant Research Ithaca New York 14853; Present address: USDA-ARS Plant Genetics Research Unit Columbia Missouri 65211
| | - Georg Jander
- Boyce Thompson Institute for Plant Research Ithaca New York 14853
| | - Noah K Whiteman
- Ecology and Evolutionary Biology University of Arizona Tucson Arizona 85721; Rocky Mountain Biological Laboratory Gothic Colorado 81224; Present address: Department of Integrative Biology University of California Berkeley California 94720
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130
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Kaplan I, Carrillo J, Garvey M, Ode PJ. Indirect plant-parasitoid interactions mediated by changes in herbivore physiology. CURRENT OPINION IN INSECT SCIENCE 2016; 14:112-119. [PMID: 27436656 DOI: 10.1016/j.cois.2016.03.004] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/09/2015] [Revised: 02/28/2016] [Accepted: 03/02/2016] [Indexed: 06/06/2023]
Abstract
In occupying an intermediate trophic position, herbivorous insects serve a vital link between plants at the base of the food chain and parasitoids at the top. Although these herbivore-mediated indirect plant-parasitoid interactions are well-documented, new studies have uncovered previously undescribed mechanisms that are fundamentally changing how we view tri-trophic relationships. In this review we highlight recent advances in this field focusing on both plant-driven and parasitoid-driven outcomes that flow up and down the trophic web, respectively. From the bottom-up, plant metabolites can impact parasitoid success by altering host immune function; however, few have considered the potential effects of other plant defense strategies such as tolerance on parasitoid ecology and behavior. From the top-down, parasitoids have long been considered plant bodyguards, but in reality the consequences of parasitism for herbivory rates and induction of plant defensive chemistry are far more complicated with cascading effects on community-level interactions.
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Affiliation(s)
- Ian Kaplan
- Department of Entomology, Purdue University, United States.
| | - Juli Carrillo
- Department of Entomology, Purdue University, United States
| | - Michael Garvey
- Department of Entomology, Purdue University, United States
| | - Paul J Ode
- Department of Bioagricultural Sciences & Pest Management, Colorado State University, United States
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131
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Singer MS. Behaviorally plastic host-plant use by larval Lepidoptera in tri-trophic food webs. CURRENT OPINION IN INSECT SCIENCE 2016; 14:56-60. [PMID: 27436647 DOI: 10.1016/j.cois.2016.01.005] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/16/2015] [Revised: 01/15/2016] [Accepted: 01/19/2016] [Indexed: 06/06/2023]
Abstract
Plant-insect interactions research emphasizes adaptive plasticity of plants and carnivores, such as parasitoids, implying a relatively passive role of herbivores. Current work is addressing this deficit, with exciting studies of behavioral plasticity of larval Lepidoptera (caterpillars). Here I use select examples to illustrate the diversity of behaviorally plastic host-plant use by caterpillars, including anti-predator tactics, self-medication, and evasion of dynamic plant defenses, as proof of the agency of caterpillar behavior in plant-insect interactions. I emphasize the significance of adaptive behavioral plasticity of caterpillars in the context of tri-trophic interactions. Recent research on trait-mediated indirect interactions places adaptive behavioral plasticity of herbivores at the center of community and food web dynamics, with far-reaching consequences of issues such as community stability.
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Affiliation(s)
- Michael S Singer
- Department of Biology, Wesleyan University, Middletown, CT 06459, USA.
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132
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Effects of parental care on the accumulation and release of cryptic genetic variation: review of mechanisms and a case study of dung beetles. Evol Ecol 2016. [DOI: 10.1007/s10682-015-9813-4] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
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133
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Kearney PE, Murray PJ, Hoy JM, Hohenhaus M, Kotze A. The 'Toolbox' of strategies for managing Haemonchus contortus in goats: What's in and what's out. Vet Parasitol 2016; 220:93-107. [PMID: 26995728 DOI: 10.1016/j.vetpar.2016.02.028] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2015] [Revised: 02/19/2016] [Accepted: 02/25/2016] [Indexed: 10/22/2022]
Abstract
A dynamic and innovative approach to managing the blood-consuming nematode Haemonchus contortus in goats is critical to crack dependence on veterinary anthelmintics. H. contortus management strategies have been the subject of intense research for decades, and must be selected to create a tailored, individualized program for goat farms. Through the selection and combination of strategies from the Toolbox, an effective management program for H. contortus can be designed according to the unique conditions of each particular farm. This Toolbox investigates strategies including vaccines, bioactive forages, pasture/grazing management, behavioural management, natural immunity, FAMACHA, Refugia and strategic drenching, mineral/vitamin supplementation, copper Oxide Wire Particles (COWPs), breeding and selection/selecting resistant and resilient individuals, biological control and anthelmintic drugs. Barbervax(®), the ground-breaking Haemonchus vaccine developed and currently commercially available on a pilot scale for sheep, is prime for trialling in goats and would be an invaluable inclusion to this Toolbox. The specialised behaviours of goats, specifically their preferences to browse a variety of plants and accompanying physiological adaptations to the consumption of secondary compounds contained in browse, have long been unappreciated and thus overlooked as a valuable, sustainable strategy for Haemonchus management. These strategies are discussed in this review as to their value for inclusion into the 'Toolbox' currently, and the future implications of ongoing research for goat producers. Combining and manipulating strategies such as browsing behaviour, pasture management, bioactive forages and identifying and treating individual animals for haemonchosis, in addition to continuous evaluation of strategy effectiveness, is conducted using a model farm scenario. Selecting strategies from the Toolbox, with regard to their current availability, feasibility, economical cost and potential ease of implementation depending on the systems of production and their complementary nature, is the future of managing H. contortus in farmed goats internationally and maintaining the remaining efficacy of veterinary anthelmintics.
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Affiliation(s)
- P E Kearney
- The University of Queensland, Gatton Campus, QLD, Australia.
| | - P J Murray
- The University of Queensland, Gatton Campus, QLD, Australia
| | - J M Hoy
- The University of Queensland, Gatton Campus, QLD, Australia
| | - M Hohenhaus
- The University of Queensland, Gatton Campus, QLD, Australia
| | - A Kotze
- The University of Queensland, Gatton Campus, QLD, Australia; CSIRO, Bioscience Precinct, St Lucia, QLD, Australia
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134
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Abstract
Selective pressures imposed by pathogenic microorganisms to embryos have selected in hosts for a battery of antimicrobial lines of defenses that includes physical and chemical barriers. Due to the antimicrobial properties of volatile compounds of green plants and of chemicals of feather degrading bacteria, the use of aromatic plants and feathers for nest building has been suggested as one of these barriers. However, experimental evidence suggesting such effects is scarce in the literature. During two consecutive years, we explored experimentally the effects of these nest materials on loads of different groups of bacteria (mesophilic bacteria, Enterobacteriaceae, Staphylococcus and Enterococcus) of eggshells in nests of spotless starlings (Sturnus unicolor) at the beginning and at the end of the incubation period. This was also explored in artificial nests without incubation activity. We also experimentally increased bacterial density of eggs in natural and artificial nests and explored the effects of nest lining treatments on eggshell bacterial load. Support for the hypothetical antimicrobial function of nest materials was mainly detected for the year and location with larger average values of eggshell bacterial density. The beneficial effects of feathers and plants were more easily detected in artificial nests with no incubation activity, suggesting an active role of incubation against bacterial colonization of eggshells. Pigmented and unpigmented feathers reduced eggshell bacterial load in starling nests and artificial nest boxes. Results from artificial nests allowed us to discuss and discard alternative scenarios explaining the detected association, particularly those related to the possible sexual role of feathers and aromatic plants in starling nests. All these results considered together confirm the antimicrobial functionality mainly of feathers but also of plants used as nest materials, and highlight the importance of temporally and geographically environmental variation associated with risk of bacterial proliferation determining the strength of such effects. Because of costs associated to nest building, birds should adjust nest building effort to expected bacterial environments during incubation, a prediction that should be further explored.
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135
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Maure F, Thomas F, Doyon J, Brodeur J. Host nutritional status mediates degree of parasitoid virulence. OIKOS 2016. [DOI: 10.1111/oik.02944] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Fanny Maure
- MIVEGEC/UMR CNRS-IRD-UM 5290; 911 Avenue Agropolis, BP 64501 FR-34394 Montpellier Cedex 5 France
- Inst. de recherche en biologie végétale, Dépt de sciences biologiques; Univ. de Montréal; 4101, rue Sherbrooke Est Montréal QC H1X 2B2 Canada
| | - Frédéric Thomas
- MIVEGEC/UMR CNRS-IRD-UM 5290; 911 Avenue Agropolis, BP 64501 FR-34394 Montpellier Cedex 5 France
| | - Josée Doyon
- Inst. de recherche en biologie végétale, Dépt de sciences biologiques; Univ. de Montréal; 4101, rue Sherbrooke Est Montréal QC H1X 2B2 Canada
| | - Jacques Brodeur
- Inst. de recherche en biologie végétale, Dépt de sciences biologiques; Univ. de Montréal; 4101, rue Sherbrooke Est Montréal QC H1X 2B2 Canada
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136
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Biller OM, Adler LS, Irwin RE, McAllister C, Palmer-Young EC. Possible Synergistic Effects of Thymol and Nicotine Against Crithidia bombi Parasitism in Bumble Bees. PLoS One 2015; 10:e0144668. [PMID: 26657643 PMCID: PMC4686078 DOI: 10.1371/journal.pone.0144668] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2015] [Accepted: 11/20/2015] [Indexed: 02/06/2023] Open
Abstract
Floral nectar contains secondary compounds with antimicrobial properties that can affect not only plant-pollinator interactions, but also interactions between pollinators and their parasites. Although recent work has shown that consumption of plant secondary compounds can reduce pollinator parasite loads, little is known about the effects of dosage or compound combinations. We used the generalist pollinator Bombus impatiens and its obligate gut parasite Crithidia bombi to study the effects of nectar chemistry on host-parasite interactions. In two experiments we tested (1) whether the secondary compounds thymol and nicotine act synergistically to reduce parasitism, and (2) whether dietary thymol concentration affects parasite resistance. In both experiments, uninfected Bombus impatiens were inoculated with Crithidia and then fed particular diet treatments for 7 days, after which infection levels were assessed. In the synergism experiment, thymol and nicotine alone and in combination did not significantly affect parasite load or host mortality. However, the thymol-nicotine combination treatment reduced log-transformed parasite counts by 30% relative to the control group (P = 0.08). For the experiment in which we manipulated thymol concentration, we found no significant effect of any thymol concentration on Crithidia load, but moderate (2 ppm) thymol concentrations incurred a near-significant increase in mortality (P = 0.054). Our results tentatively suggest the value of a mixed diet for host immunity, yet contrast with research on the antimicrobial activity of dietary thymol and nicotine in vertebrate and other invertebrate systems. We suggest that future research evaluate genetic variation in Crithidia virulence, multi-strain competition, and Crithidia interactions with the gut microbe community that may mediate antimicrobial activities of secondary compounds.
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Affiliation(s)
- Olivia Masi Biller
- Department of Biology, University of Massachusetts at Amherst, Amherst, Massachusetts, United States of America
| | - Lynn S. Adler
- Department of Biology, University of Massachusetts at Amherst, Amherst, Massachusetts, United States of America
| | - Rebecca E. Irwin
- Department of Biology, Dartmouth College, Hanover, New Hampshire, United States of America
| | - Caitlin McAllister
- Department of Biology, University of Massachusetts at Amherst, Amherst, Massachusetts, United States of America
| | - Evan C. Palmer-Young
- Department of Biology, University of Massachusetts at Amherst, Amherst, Massachusetts, United States of America
- * E-mail:
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137
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Provenza FD, Meuret M, Gregorini P. Our landscapes, our livestock, ourselves: Restoring broken linkages among plants, herbivores, and humans with diets that nourish and satiate. Appetite 2015; 95:500-19. [DOI: 10.1016/j.appet.2015.08.004] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2015] [Revised: 07/25/2015] [Accepted: 08/01/2015] [Indexed: 02/06/2023]
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138
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Hess A, McAllister C, DeMarchi J, Zidek M, Murone J, Venesky MD. Salamanders increase their feeding activity when infected with the pathogenic chytrid fungus Batrachochytrium dendrobatidis. DISEASES OF AQUATIC ORGANISMS 2015; 116:205-212. [PMID: 26503775 DOI: 10.3354/dao02915] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Immune function is a costly line of defense against parasitism. When infected with a parasite, hosts frequently lose mass due to these costs. However, some infected hosts (e.g. highly resistant individuals) can clear infections with seemingly little fitness losses, but few studies have tested how resistant hosts mitigate these costly immune defenses. We explored this topic using eastern red-backed salamanders Plethodon cinereus and the fungal pathogen Batrachochytrium dendrobatidis (Bd). Bd is generally lethal for amphibians, and stereotypical symptoms of infection include loss in mass and deficits in feeding. However, individuals of P. cinereus can clear their Bd infections with seemingly few fitness costs. We conducted an experiment in which we repeatedly observed the feeding activity of Bd-infected and non-infected salamanders. We found that Bd-infected salamanders generally increased their feeding activity compared to non-infected salamanders. The fact that we did not observe any differences in mass change between the treatments suggests that increased feeding might help Bd-infected salamanders minimize the costs of an effective immune response.
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Affiliation(s)
- Alexandra Hess
- Department of Biology, Allegheny College, Meadville, PA 16335, USA
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139
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Bowler M, Messer EJE, Claidière N, Whiten A. Mutual medication in capuchin monkeys - Social anointing improves coverage of topically applied anti-parasite medicines. Sci Rep 2015; 5:15030. [PMID: 26456539 PMCID: PMC4601033 DOI: 10.1038/srep15030] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2015] [Accepted: 08/21/2015] [Indexed: 12/02/2022] Open
Abstract
Wild and captive capuchin monkeys will anoint themselves with a range of strong smelling substances including millipedes, ants, limes and onions. Hypotheses for the function of the behaviour range from medicinal to social. However, capuchin monkeys may anoint in contact with other individuals, as well as individually. The function of social anointing has also been explained as either medicinal or to enhance social bonding. By manipulating the abundance of an anointing resource given to two groups of tufted capuchins, we tested predictions derived from the main hypotheses for the functions of anointing and in particular, social anointing. Monkeys engaged in individual and social anointing in similar proportions when resources were rare or common, and monkeys holding resources continued to join anointing groups, indicating that social anointing has functions beyond that of gaining access to resources. The distribution of individual and social anointing actions on the monkeys’ bodies supports a medicinal function for both individual and social anointing, that requires no additional social bonding hypotheses. Individual anointing targets hard-to-see body parts that are harder to groom, whilst social anointing targets hard-to-reach body parts. Social anointing in capuchins is a form of mutual medication that improves coverage of topically applied anti-parasite medicines.
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Affiliation(s)
- Mark Bowler
- School of Psychology &Neuroscience, University of St Andrews, St Andrews, Scotland, United Kingdom.,San Diego Zoo Global Institute for Conservation Research, 15600 San Pasqual Valley Road, Escondido, CA 92027-700, USA
| | - Emily J E Messer
- School of Psychology &Neuroscience, University of St Andrews, St Andrews, Scotland, United Kingdom.,School of Life Sciences Heriot Watt University, Edinburgh, Scotland, United Kingdom
| | - Nicolas Claidière
- School of Psychology &Neuroscience, University of St Andrews, St Andrews, Scotland, United Kingdom.,Aix Marseille Université, Centre National de la Recherche Scientifique, Laboratoire de Psychologie Cognitive, Unité Mixte de Recherche 7290, Marseille, France
| | - Andrew Whiten
- School of Psychology &Neuroscience, University of St Andrews, St Andrews, Scotland, United Kingdom
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140
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Bos N, Sundström L, Fuchs S, Freitak D. Ants medicate to fight disease. Evolution 2015; 69:2979-84. [PMID: 26283006 DOI: 10.1111/evo.12752] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2015] [Revised: 07/22/2015] [Accepted: 07/23/2015] [Indexed: 02/05/2023]
Abstract
Parasites are ubiquitous, and the ability to defend against these is of paramount importance. One way to fight diseases is self-medication, which occurs when an organism consumes biologically active compounds to clear, inhibit, or alleviate disease symptoms. Here, we show for the first time that ants selectively consume harmful substances (reactive oxygen species, ROS) upon exposure to a fungal pathogen, yet avoid these in the absence of infection. This increased intake of ROS, while harmful to healthy ants, leads to higher survival of exposed ants. The fact that ingestion of this substance carries a fitness cost in the absence of pathogens rules out compensatory diet choice as the mechanism, and provides evidence that social insects medicate themselves against fungal infection, using a substance that carries a fitness cost to uninfected individuals.
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Affiliation(s)
- Nick Bos
- Centre of Excellence in Biological Interactions, University of Helsinki, Finland. .,Tvärminne Zoological Station, University of Helsinki, Finland.
| | - Liselotte Sundström
- Centre of Excellence in Biological Interactions, University of Helsinki, Finland.,Tvärminne Zoological Station, University of Helsinki, Finland
| | - Siiri Fuchs
- Centre of Excellence in Biological Interactions, University of Helsinki, Finland.,Tvärminne Zoological Station, University of Helsinki, Finland
| | - Dalial Freitak
- Centre of Excellence in Biological Interactions, University of Helsinki, Finland.,Tvärminne Zoological Station, University of Helsinki, Finland.,Centre of Excellence in Biological Interactions, University of Jyväskylä, Finland
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141
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Biological warfare: Microorganisms as drivers of host-parasite interactions. INFECTION GENETICS AND EVOLUTION 2015; 34:251-9. [PMID: 26026593 DOI: 10.1016/j.meegid.2015.05.027] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/03/2015] [Revised: 05/26/2015] [Accepted: 05/27/2015] [Indexed: 01/08/2023]
Abstract
Understanding parasite strategies for evasion, manipulation or exploitation of hosts is crucial for many fields, from ecology to medical sciences. Generally, research has focused on either the host response to parasitic infection, or the parasite virulence mechanisms. More recently, integrated studies of host-parasite interactions have allowed significant advances in theoretical and applied biology. However, these studies still provide a simplistic view of these as mere two-player interactions. Host and parasite are associated with a myriad of microorganisms that could benefit from the improved fitness of their partner. Illustrations of such complex multi-player interactions have emerged recently from studies performed in various taxa. In this conceptual article, we propose how these associated microorganisms may participate in the phenotypic alterations induced by parasites and hence in host-parasite interactions, from an ecological and evolutionary perspective. Host- and parasite-associated microorganisms may participate in the host-parasite interaction by interacting directly or indirectly with the other partner. As a result, parasites may develop (i) the disruptive strategy in which the parasite alters the host microbiota to its advantage, and (ii) the biological weapon strategy where the parasite-associated microorganism contributes to or modulates the parasite's virulence. Some phenotypic alterations induced by parasite may also arise from conflicts of interests between the host or parasite and its associated microorganism. For each situation, we review the literature and propose new directions for future research. Specifically, investigating the role of host- and parasite-associated microorganisms in host-parasite interactions at the individual, local and regional level will lead to a holistic understanding of how the co-evolution of the different partners influences how the other ones respond, both ecologically and evolutionary. The conceptual framework we propose here is important and relevant to understand the proximate basis of parasite strategies, to predict their evolutionary dynamics and potentially to prevent therapeutic failures.
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142
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Kappeler PM, Cremer S, Nunn CL. Sociality and health: impacts of sociality on disease susceptibility and transmission in animal and human societies. Philos Trans R Soc Lond B Biol Sci 2015; 370:20140116. [PMID: 25870402 PMCID: PMC4410382 DOI: 10.1098/rstb.2014.0116] [Citation(s) in RCA: 140] [Impact Index Per Article: 15.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/06/2015] [Indexed: 02/06/2023] Open
Abstract
This paper introduces a theme issue presenting the latest developments in research on the impacts of sociality on health and fitness. The articles that follow cover research on societies ranging from insects to humans. Variation in measures of fitness (i.e. survival and reproduction) has been linked to various aspects of sociality in humans and animals alike, and variability in individual health and condition has been recognized as a key mediator of these relationships. Viewed from a broad evolutionary perspective, the evolutionary transitions from a solitary lifestyle to group living have resulted in several new health-related costs and benefits of sociality. Social transmission of parasites within groups represents a major cost of group living, but some behavioural mechanisms, such as grooming, have evolved repeatedly to reduce this cost. Group living also has created novel costs in terms of altered susceptibility to infectious and non-infectious disease as a result of the unavoidable physiological consequences of social competition and integration, which are partly alleviated by social buffering in some vertebrates. Here, we define the relevant aspects of sociality, summarize their health-related costs and benefits, and discuss possible fitness measures in different study systems. Given the pervasive effects of social factors on health and fitness, we propose a synthesis of existing conceptual approaches in disease ecology, ecological immunology and behavioural neurosciences by adding sociality as a key factor, with the goal to generate a broader framework for organismal integration of health-related research.
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Affiliation(s)
- Peter M Kappeler
- Behavioral Ecology and Sociobiology Unit, German Primate Center, Göttingen, Germany Department of Sociobiology/Anthropology, University of Göttingen, Göttingen, Germany
| | - Sylvia Cremer
- IST Austria (Institute of Science and Technology Austria), Klosterneuburg, Austria
| | - Charles L Nunn
- Department of Evolutionary Anthropology, Duke University, Durham, NC, USA Duke Global Health Institute, Duke University, Durham, NC, USA
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143
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144
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Pinheiro MM, Ahmed MA, Millar SB, Sanderson T, Otto TD, Lu WC, Krishna S, Rayner JC, Cox-Singh J. Plasmodium knowlesi genome sequences from clinical isolates reveal extensive genomic dimorphism. PLoS One 2015; 10:e0121303. [PMID: 25830531 PMCID: PMC4382175 DOI: 10.1371/journal.pone.0121303] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2014] [Accepted: 01/30/2015] [Indexed: 11/21/2022] Open
Abstract
Plasmodium knowlesi is a newly described zoonosis that causes malaria in the human population that can be severe and fatal. The study of P. knowlesi parasites from human clinical isolates is relatively new and, in order to obtain maximum information from patient sample collections, we explored the possibility of generating P. knowlesi genome sequences from archived clinical isolates. Our patient sample collection consisted of frozen whole blood samples that contained excessive human DNA contamination and, in that form, were not suitable for parasite genome sequencing. We developed a method to reduce the amount of human DNA in the thawed blood samples in preparation for high throughput parasite genome sequencing using Illumina HiSeq and MiSeq sequencing platforms. Seven of fifteen samples processed had sufficiently pure P. knowlesi DNA for whole genome sequencing. The reads were mapped to the P. knowlesi H strain reference genome and an average mapping of 90% was obtained. Genes with low coverage were removed leaving 4623 genes for subsequent analyses. Previously we identified a DNA sequence dimorphism on a small fragment of the P. knowlesi normocyte binding protein xa gene on chromosome 14. We used the genome data to assemble full-length Pknbpxa sequences and discovered that the dimorphism extended along the gene. An in-house algorithm was developed to detect SNP sites co-associating with the dimorphism. More than half of the P. knowlesi genome was dimorphic, involving genes on all chromosomes and suggesting that two distinct types of P. knowlesi infect the human population in Sarawak, Malaysian Borneo. We use P. knowlesi clinical samples to demonstrate that Plasmodium DNA from archived patient samples can produce high quality genome data. We show that analyses, of even small numbers of difficult clinical malaria isolates, can generate comprehensive genomic information that will improve our understanding of malaria parasite diversity and pathobiology.
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Affiliation(s)
- Miguel M. Pinheiro
- School of Medicine, University of St Andrews, Medical and Biological Sciences Building, North Haugh, St Andrews, United Kingdom
| | - Md Atique Ahmed
- Malaria Research Centre, University Malaysia Sarawak, Kuching, Sarawak, Malaysia
| | - Scott B. Millar
- School of Medicine, University of St Andrews, Medical and Biological Sciences Building, North Haugh, St Andrews, United Kingdom
| | - Theo Sanderson
- Malaria Programme, Wellcome Trust Sanger Institute, Wellcome Trust Genome Campus, Hinxton, Cambridge, United Kingdom
| | - Thomas D. Otto
- Malaria Programme, Wellcome Trust Sanger Institute, Wellcome Trust Genome Campus, Hinxton, Cambridge, United Kingdom
| | - Woon Chan Lu
- Sarikei Hospital, Sarikei, Sarawak, 96100, Malaysia
| | - Sanjeev Krishna
- Division of Clinical Sciences, St. George’s, University of London, London, United Kingdom
| | - Julian C. Rayner
- Malaria Programme, Wellcome Trust Sanger Institute, Wellcome Trust Genome Campus, Hinxton, Cambridge, United Kingdom
| | - Janet Cox-Singh
- School of Medicine, University of St Andrews, Medical and Biological Sciences Building, North Haugh, St Andrews, United Kingdom
- * E-mail:
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145
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Richardson LL, Adler LS, Leonard AS, Andicoechea J, Regan KH, Anthony WE, Manson JS, Irwin RE. Secondary metabolites in floral nectar reduce parasite infections in bumblebees. Proc Biol Sci 2015; 282:20142471. [PMID: 25694627 PMCID: PMC4345440 DOI: 10.1098/rspb.2014.2471] [Citation(s) in RCA: 128] [Impact Index Per Article: 14.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2014] [Accepted: 01/14/2015] [Indexed: 11/12/2022] Open
Abstract
The synthesis of secondary metabolites is a hallmark of plant defence against herbivores. These compounds may be detrimental to consumers, but can also protect herbivores against parasites. Floral nectar commonly contains secondary metabolites, but little is known about the impacts of nectar chemistry on pollinators, including bees. We hypothesized that nectar secondary metabolites could reduce bee parasite infection. We inoculated individual bumblebees with Crithidia bombi, an intestinal parasite, and tested effects of eight naturally occurring nectar chemicals on parasite population growth. Secondary metabolites strongly reduced parasite load, with significant effects of alkaloids, terpenoids and iridoid glycosides ranging from 61 to 81%. Using microcolonies, we also investigated costs and benefits of consuming anabasine, the compound with the strongest effect on parasites, in infected and uninfected bees. Anabasine increased time to egg laying, and Crithidia reduced bee survival. However, anabasine consumption did not mitigate the negative effects of Crithidia, and Crithidia infection did not alter anabasine consumption. Our novel results highlight that although secondary metabolites may not rescue survival in infected bees, they may play a vital role in mediating Crithidia transmission within and between colonies by reducing Crithidia infection intensities.
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Affiliation(s)
- Leif L Richardson
- Department of Biological Sciences, Dartmouth College, Hanover, NH 03755, USA
| | - Lynn S Adler
- Biology Department, University of Massachusetts, Amherst, MA 01003, USA
| | - Anne S Leonard
- Biology Department, University of Massachusetts, Amherst, MA 01003, USA
| | | | - Karly H Regan
- Biology Department, University of Massachusetts, Amherst, MA 01003, USA
| | - Winston E Anthony
- Biology Department, University of Massachusetts, Amherst, MA 01003, USA
| | - Jessamyn S Manson
- Department of Biological Sciences, Dartmouth College, Hanover, NH 03755, USA
| | - Rebecca E Irwin
- Department of Biological Sciences, Dartmouth College, Hanover, NH 03755, USA
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Baracchi D, Brown MJF, Chittka L. Weak and contradictory effects of self-medication with nectar nicotine by parasitized bumblebees. F1000Res 2015; 4:73. [PMID: 25949807 PMCID: PMC4406194 DOI: 10.12688/f1000research.6262.1] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 03/17/2015] [Indexed: 11/20/2022] Open
Abstract
The presence of antimicrobial secondary metabolites in nectar suggests that pollinators, which are threatened globally by emergent disease, may benefit from the consumption of nectars rich in these metabolites. We tested whether nicotine, a nectar secondary metabolite common in Solenaceae and Tilia species, is used by parasitized bumblebees as a source of self-medication , using a series of toxicological, microbiological and behavioural experiments. Caged bees infected with Crithidia bombi [TI1] had a slight preference for sucrose solution laced with the alkaloid and behavioural tests showed that the parasite infection induced an increased consumption of nicotine during foraging activity. When ingested, nicotine delayed the progression of a gut infection in bumblebees by a few days, but dietary nicotine did not clear the infection, and after 10 days the parasite load approached that of control bees. Moreover, when pathogens were exposed to the alkaloid prior to host ingestion the protozoan's viability was not directly affected, suggesting that anti-parasite effects were relatively weak. Nicotine consumption in a single dose did not impose any cost even in food-stressed bees (starved) but the alkaloid had detrimental effects on healthy bees if consistently consumed for weeks. These toxic effects disappeared in infected bees suggesting that detoxification costs might have been counterbalanced by the advantages in slowing the progression of the infection. Nonetheless we did not find a benefit of nicotine consumption in terms of life expectancy of infected bees, making these findings difficult to interpret. Our results indicate that caution is warranted in interpreting impacts of plant metabolites on insect parasites and suggest that the conditions under which nicotine consumption provides benefits to either bees or plants remain to be identified. The contention that secondary metabolites in nectar may be under selection from pollinators, or used by plants to enhance their own reproductive success, remains to be confirmed.
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Affiliation(s)
- David Baracchi
- Department of Biological and Experimental Psychology, School of Biological and Chemical Sciences, Queen Mary University of London, Mile End Road, London, E1 4NS, UK
| | - Mark J. F. Brown
- School of Biological Sciences, Royal Holloway University of London, Egham, Surrey, TW20 0EX, UK
| | - Lars Chittka
- Department of Biological and Experimental Psychology, School of Biological and Chemical Sciences, Queen Mary University of London, Mile End Road, London, E1 4NS, UK
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Abstract
The presence of antimicrobial secondary metabolites in nectar suggests that pollinators, which are threatened globally by emergent disease, may benefit from the consumption of nectars rich in these metabolites. We tested whether nicotine, a nectar secondary metabolite common in Solanaceae and Tilia species, is used by parasitized bumblebees as a source of self-medication , using a series of toxicological, microbiological and behavioural experiments. Caged bees infected with Crithidia bombi had a slight preference for sucrose solution laced with the alkaloid and behavioural tests showed that the parasite infection induced an increased consumption of nicotine during foraging activity, though nicotine had an appetite-reducing effect overall. When ingested, nicotine delayed the progression of a gut infection in bumblebees by a few days, but dietary nicotine did not clear the infection, and after 10 days the parasite load approached that of control bees. Moreover, when pathogens were exposed to the alkaloid prior to host ingestion, the protozoan's viability was not directly affected, suggesting that anti-parasite effects were relatively weak. Nicotine consumption in a single dose did not impose any cost even in starved bees but the alkaloid had detrimental effects on healthy bees if consistently consumed for weeks. These toxic effects disappeared in infected bees, suggesting that detoxification costs might have been counterbalanced by the advantages in slowing the progression of the infection. Nicotine consumption did not affect bee lifespan but the reduction in the parasite load may have other likely unexplored subtle benefits both for individual bees and their colony. Potential evidence for self-medication is discussed. The contention that secondary metabolites in nectar may be under selection from pollinators, or used by plants to enhance their own reproductive success, remains to be confirmed.
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Affiliation(s)
- David Baracchi
- Department of Biological and Experimental Psychology, School of Biological and Chemical Sciences, Queen Mary University of London, Mile End Road, London, E1 4NS, UK
| | - Mark J. F. Brown
- School of Biological Sciences, Royal Holloway University of London, Egham, Surrey, TW20 0EX, UK
| | - Lars Chittka
- Department of Biological and Experimental Psychology, School of Biological and Chemical Sciences, Queen Mary University of London, Mile End Road, London, E1 4NS, UK
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Abstract
The presence of antimicrobial secondary metabolites in nectar suggests that pollinators, which are threatened globally by emergent disease, may benefit from the consumption of nectars rich in these metabolites. We tested whether nicotine, a nectar secondary metabolite common in Solanaceae and Tilia species, is used by parasitized bumblebees as a source of self-medication , using a series of toxicological, microbiological and behavioural experiments. Caged bees infected with Crithidia bombi had a slight preference for sucrose solution laced with the alkaloid and behavioural tests showed that the parasite infection induced an increased consumption of nicotine during foraging activity, though nicotine had an appetite-reducing effect overall. When ingested, nicotine delayed the progression of a gut infection in bumblebees by a few days, but dietary nicotine did not clear the infection, and after 10 days the parasite load approached that of control bees. Moreover, when pathogens were exposed to the alkaloid prior to host ingestion, the protozoan's viability was not directly affected, suggesting that anti-parasite effects were relatively weak. Nicotine consumption in a single dose did not impose any cost even in starved bees but the alkaloid had detrimental effects on healthy bees if consistently consumed for weeks. These toxic effects disappeared in infected bees, suggesting that detoxification costs might have been counterbalanced by the advantages in slowing the progression of the infection. Nicotine consumption did not affect bee lifespan but the reduction in the parasite load may have other likely unexplored subtle benefits both for individual bees and their colony. Potential evidence for self-medication is discussed. The contention that secondary metabolites in nectar may be under selection from pollinators, or used by plants to enhance their own reproductive success, remains to be confirmed.
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Affiliation(s)
- David Baracchi
- Department of Biological and Experimental Psychology, School of Biological and Chemical Sciences, Queen Mary University of London, Mile End Road, London, E1 4NS, UK
| | - Mark J. F. Brown
- School of Biological Sciences, Royal Holloway University of London, Egham, Surrey, TW20 0EX, UK
| | - Lars Chittka
- Department of Biological and Experimental Psychology, School of Biological and Chemical Sciences, Queen Mary University of London, Mile End Road, London, E1 4NS, UK
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Affiliation(s)
- Peri A. Mason
- Department of Ecology and Evolutionary Biology University of Colorado Boulder UCB 334 Colorado 80309 USA
| | - Michael S. Singer
- Biology Department Wesleyan University Middletown Connecticut 06459 USA
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