1
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Agrawal AA, Hastings AP, Duplais C. Testing the selective sequestration hypothesis: Monarch butterflies preferentially sequester plant defences that are less toxic to themselves while maintaining potency to others. Ecol Lett 2024; 27:e14340. [PMID: 38017619 DOI: 10.1111/ele.14340] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2023] [Revised: 10/08/2023] [Accepted: 10/23/2023] [Indexed: 11/30/2023]
Abstract
Herbivores that sequester toxins are thought to have cracked the code of plant defences. Nonetheless, coevolutionary theory predicts that plants should evolve toxic variants that also negatively impact specialists. We propose and test the selective sequestration hypothesis, that specialists preferentially sequester compounds that are less toxic to themselves while maintaining toxicity to enemies. Using chemically distinct plants, we show that monarch butterflies sequester only a subset of cardenolides from milkweed leaves that are less potent against their target enzyme (Na+ /K+ -ATPase) compared to several dominant cardenolides from leaves. However, sequestered compounds remain highly potent against sensitive Na+ /K+ -ATPases found in most predators. We confirmed this differential toxicity with mixtures of purified cardenolides from leaves and butterflies. The genetic basis of monarch adaptation to sequestered cardenolides was also confirmed with transgenic Drosophila that were CRISPR-edited with the monarch's Na+ /K+ -ATPase. Thus, the monarch's selective sequestration appears to reduce self-harm while maintaining protection from enemies.
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Affiliation(s)
- Anurag A Agrawal
- Department of Ecology and Evolutionary Biology, Cornell University, Ithaca, New York, USA
- Department of Entomology, Cornell University, Ithaca, New York, USA
| | - Amy P Hastings
- Department of Ecology and Evolutionary Biology, Cornell University, Ithaca, New York, USA
| | - Christophe Duplais
- Department of Entomology, Cornell AgriTech, Cornell University, Geneva, New York, USA
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2
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Burger H, Buttala S, Koch H, Ayasse M, Johnson SD, Stevenson PC. Nectar cardenolides and floral volatiles mediate a specialized wasp pollination system. J Exp Biol 2024; 227:jeb246156. [PMID: 38180227 PMCID: PMC10785657 DOI: 10.1242/jeb.246156] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2023] [Accepted: 11/15/2023] [Indexed: 01/06/2024]
Abstract
Specialization in plant pollination systems can arise from traits that function as filters of flower visitors. This may involve chemical traits such as floral volatiles that selectively attract favoured visitors and non-volatile nectar constituents that selectively deter disfavoured visitors through taste or longer-term toxic effects or both. We explored the functions of floral chemical traits in the African milkweed Gomphocarpus physocarpus, which is pollinated almost exclusively by vespid wasps, despite having nectar that is highly accessible to other insects such as honeybees. We demonstrated that the nectar of wasp-pollinated G. physocarpus contains cardenolides that had greater toxic effects on Apis mellifera honeybees than on Vespula germanica wasps, and also reduced feeding rates by honeybees. Behavioural experiments using natural compositions of nectar compounds showed that these interactions are mediated by non-volatile nectar chemistry. We also identified volatile compounds with acetic acid as a main component in the floral scent of G. physocarpus that elicited electrophysiological responses in wasp antennae. Mixtures of these compounds were behaviourally effective for attraction of V. germanica wasps. The results show the importance of both volatile and non-volatile chemical traits as filters that lead to specialization in plant pollination systems.
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Affiliation(s)
- Hannah Burger
- Evolutionary Ecology and Conservation Genomics, Ulm University, 89081 Ulm, Germany
| | - Samantha Buttala
- Evolutionary Ecology and Conservation Genomics, Ulm University, 89081 Ulm, Germany
| | - Hauke Koch
- Royal Botanic Gardens, Kew,Kew Green, Richmond TW9 3AE, UK
| | - Manfred Ayasse
- Evolutionary Ecology and Conservation Genomics, Ulm University, 89081 Ulm, Germany
| | - Steven D. Johnson
- Centre for Functional Biodiversity, School of Life Sciences, University of KwaZulu-Natal, Scottsville, Pietermaritzburg 3209, South Africa
| | - Philip C. Stevenson
- Royal Botanic Gardens, Kew,Kew Green, Richmond TW9 3AE, UK
- Natural Resources Institute, University of Greenwich, Chatham Maritime, Kent ME4 4TB, UK
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3
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Petzel-Witta S, Wunder C, Pogoda W, Toennes SW, Mebs D. Missed chances? Sequestration and non-sequestration of alkaloids by moths (Lepidoptera). Toxicon 2023; 227:107098. [PMID: 36990229 DOI: 10.1016/j.toxicon.2023.107098] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2023] [Revised: 03/20/2023] [Accepted: 03/22/2023] [Indexed: 03/30/2023]
Abstract
Some butterflies and moths sequester and retain noxious phytochemicals for defence against predators. In the present study, three moth species, the garden tiger moth, Arctia caja, the death hawk moth, Acherontia atropos, and the oleander hawk moth, Daphnis nerii, were tested whether they sequester alkaloids from their host plants. Whereas A. caja consistently sequestered atropine from Atropa belladonna, also when atropine sulfate was added to the alkaloid-free diet of the larvae, A. atropos and D. nerii were found to be unable to sequester alkaloids, neither atropine nor eburnamenine from Vinca major, respectively. Instead of acquiring toxicity as chemical defence, nocturnal lifestyle and cryptic attitudes may improve their chances of survival.
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4
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Brooks OL, James JJ, Saporito RA. Maternal chemical defenses predict offspring defenses in a dendrobatid poison frog. Oecologia 2023; 201:385-396. [PMID: 36637523 DOI: 10.1007/s00442-023-05314-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2022] [Accepted: 01/03/2023] [Indexed: 01/14/2023]
Abstract
Within and among populations, alkaloid defenses of the strawberry poison frog (Oophaga pumilio) vary spatially, temporally, and with life history stage. Natural variation in defense has been implicated as a critical factor in determining the level of protection afforded against predators and pathogens. Oophaga pumilio tadpoles sequester alkaloids from nutritive eggs and are, thus, entirely dependent on their mothers for their defense. However, it remains unclear how tadpole alkaloid composition relates to that of its mother and how variation in maternally provisioned defenses might result in varying levels of protection against predators. Here, we demonstrate that natural variation in the alkaloid composition of a mother frog is reflected as variation in her tadpole's alkaloid composition. Tadpoles, like mother frogs, varied in their alkaloid composition but always contained the identical alkaloids found in their mother. Alkaloid quantity in tadpoles was highly correlated with alkaloid quantity in their mothers. Additionally, alkaloid quantity was the best predictor of tadpole palatability, wherein tadpoles with higher alkaloid quantities were less palatable. Mother frogs with greater quantities of alkaloids are, thus, providing better protection for their offspring by provisioning chemical defenses during one of the most vulnerable periods of life.
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Affiliation(s)
- Olivia L Brooks
- School of Biological Sciences, Illinois State University, Normal, IL, 61701, USA.,Department of Biology, John Carroll University, University Heights, OH, 44118, USA
| | - Jessie J James
- Department of Biology, San Francisco State University, San Francisco, CA, 94132, USA
| | - Ralph A Saporito
- Department of Biology, John Carroll University, University Heights, OH, 44118, USA.
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5
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Blount JD, Rowland HM, Mitchell C, Speed MP, Ruxton GD, Endler JA, Brower LP. The price of defence: toxins, visual signals and oxidative state in an aposematic butterfly. Proc Biol Sci 2023; 290:20222068. [PMID: 36651049 PMCID: PMC9845971 DOI: 10.1098/rspb.2022.2068] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
In a variety of aposematic species, the conspicuousness of an individual's warning signal and the quantity of its chemical defence are positively correlated. This apparent honest signalling is predicted by resource competition models which assume that the production and maintenance of aposematic defences compete for access to antioxidant molecules that have dual functions as pigments and in protecting against oxidative damage. To test for such trade-offs, we raised monarch butterflies (Danaus plexippus) on different species of their milkweed host plants (Apocynaceae) that vary in quantities of cardenolides to test whether (i) the sequestration of cardenolides as a secondary defence is associated with costs in the form of oxidative lipid damage and reduced antioxidant defences; and (ii) lower oxidative state is associated with a reduced capacity to produce aposematic displays. In male monarchs conspicuousness was explained by an interaction between oxidative damage and sequestration: males with high levels of oxidative damage became less conspicuous with increased sequestration of cardenolides, whereas those with low oxidative damage became more conspicuous with increased levels of cardenolides. There was no significant effect of oxidative damage or concentration of sequestered cardenolides on female conspicuousness. Our results demonstrate a physiological linkage between the production of coloration and oxidative state, and differential costs of sequestration and signalling in monarch butterflies.
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Affiliation(s)
- Jonathan D. Blount
- Centre for Ecology and Conservation, College of Life and Environmental Sciences, University of Exeter, Penryn Campus, Cornwall TR10 9FE, UK
| | - Hannah M. Rowland
- Research Group Predators and Toxic Prey, Max Planck Institute for Chemical Ecology, Hans-Knöll-Straße 8, Jena, 07745, Germany
| | - Christopher Mitchell
- Centre for Ecology and Conservation, College of Life and Environmental Sciences, University of Exeter, Penryn Campus, Cornwall TR10 9FE, UK
| | - Michael P. Speed
- Institute of Systems, Molecular and Integrative Biology, University of Liverpool, Liverpool L69 7BE, UK
| | - Graeme D. Ruxton
- School of Biology, Sir Harold Mitchell Building, Greenside Place, St Andrews, UK
| | - John A. Endler
- Centre for Integrative Ecology, School of Life and Environmental Sciences, Deakin University, Waurn Ponds, Victoria 3216, Australia
| | - Lincoln P. Brower
- Department of Biology, Sweet Briar College, Sweet Briar, VA 24595, USA
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6
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Mohammadi S, Yang L, Bulbert M, Rowland HM. Defence mitigation by predators of chemically defended prey integrated over the predation sequence and across biological levels with a focus on cardiotonic steroids. ROYAL SOCIETY OPEN SCIENCE 2022; 9:220363. [PMID: 36133149 PMCID: PMC9449480 DOI: 10.1098/rsos.220363] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/13/2022] [Accepted: 08/17/2022] [Indexed: 05/10/2023]
Abstract
Predator-prey interactions have long served as models for the investigation of adaptation and fitness in natural environments. Anti-predator defences such as mimicry and camouflage provide some of the best examples of evolution. Predators, in turn, have evolved sensory systems, cognitive abilities and physiological resistance to prey defences. In contrast to prey defences which have been reviewed extensively, the evolution of predator counter-strategies has received less attention. To gain a comprehensive view of how prey defences can influence the evolution of predator counter-strategies, it is essential to investigate how and when selection can operate. In this review we evaluate how predators overcome prey defences during (i) encounter, (ii) detection, (iii) identification, (iv) approach, (v) subjugation, and (vi) consumption. We focus on prey that are protected by cardiotonic steroids (CTS)-defensive compounds that are found in a wide range of taxa, and that have a specific physiological target. In this system, coevolution is well characterized between specialist insect herbivores and their host plants but evidence for coevolution between CTS-defended prey and their predators has received less attention. Using the predation sequence framework, we organize 574 studies reporting predators overcoming CTS defences, integrate these counter-strategies across biological levels of organization, and discuss the costs and benefits of attacking CTS-defended prey. We show that distinct lineages of predators have evolved dissecting behaviour, changes in perception of risk and of taste perception, and target-site insensitivity. We draw attention to biochemical, hormonal and microbiological strategies that have yet to be investigated as predator counter-adaptations to CTS defences. We show that the predation sequence framework will be useful for organizing future studies of chemically mediated systems and coevolution.
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Affiliation(s)
- Shabnam Mohammadi
- School of Biological Sciences, University of Nebraska, Lincoln, NE, USA
- Institut für Zell- und Systembiologie der Tiere, Universität Hamburg, Hamburg, Germany
- Max Planck Institute for Chemical Ecology, Jena, Germany
| | - Lu Yang
- Wellcome Sanger Institute, Cambridge, UK
| | - Matthew Bulbert
- Department of Biological Sciences, Macquarie University North Ryde, New South Wales, Australia
- Department of Biological and Medical Sciences, Faculty of Health and Life Sciences, University of Oxford Brookes, Oxford, UK
- Max Planck Institute for Chemical Ecology, Jena, Germany
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7
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Mohammadi S, Yang L, Bulbert M, Rowland HM. Defence mitigation by predators of chemically defended prey integrated over the predation sequence and across biological levels with a focus on cardiotonic steroids. ROYAL SOCIETY OPEN SCIENCE 2022; 9:220363. [PMID: 36133149 DOI: 10.6084/m9.figshare.c.6168216] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 05/13/2022] [Accepted: 08/17/2022] [Indexed: 05/25/2023]
Abstract
Predator-prey interactions have long served as models for the investigation of adaptation and fitness in natural environments. Anti-predator defences such as mimicry and camouflage provide some of the best examples of evolution. Predators, in turn, have evolved sensory systems, cognitive abilities and physiological resistance to prey defences. In contrast to prey defences which have been reviewed extensively, the evolution of predator counter-strategies has received less attention. To gain a comprehensive view of how prey defences can influence the evolution of predator counter-strategies, it is essential to investigate how and when selection can operate. In this review we evaluate how predators overcome prey defences during (i) encounter, (ii) detection, (iii) identification, (iv) approach, (v) subjugation, and (vi) consumption. We focus on prey that are protected by cardiotonic steroids (CTS)-defensive compounds that are found in a wide range of taxa, and that have a specific physiological target. In this system, coevolution is well characterized between specialist insect herbivores and their host plants but evidence for coevolution between CTS-defended prey and their predators has received less attention. Using the predation sequence framework, we organize 574 studies reporting predators overcoming CTS defences, integrate these counter-strategies across biological levels of organization, and discuss the costs and benefits of attacking CTS-defended prey. We show that distinct lineages of predators have evolved dissecting behaviour, changes in perception of risk and of taste perception, and target-site insensitivity. We draw attention to biochemical, hormonal and microbiological strategies that have yet to be investigated as predator counter-adaptations to CTS defences. We show that the predation sequence framework will be useful for organizing future studies of chemically mediated systems and coevolution.
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Affiliation(s)
- Shabnam Mohammadi
- School of Biological Sciences, University of Nebraska, Lincoln, NE, USA
- Institut für Zell- und Systembiologie der Tiere, Universität Hamburg, Hamburg, Germany
- Max Planck Institute for Chemical Ecology, Jena, Germany
| | - Lu Yang
- Wellcome Sanger Institute, Cambridge, UK
| | - Matthew Bulbert
- Department of Biological Sciences, Macquarie University North Ryde, New South Wales, Australia
- Department of Biological and Medical Sciences, Faculty of Health and Life Sciences, University of Oxford Brookes, Oxford, UK
- Max Planck Institute for Chemical Ecology, Jena, Germany
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8
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Solis-Sosa R, Semeniuk CAD, Larrivée M, Cox S. Investing in monarch conservation: understanding private funding dynamics. FRONTIERS IN CONSERVATION SCIENCE 2022. [DOI: 10.3389/fcosc.2022.903132] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Non-profit environmental organizations (NGOs) rely heavily on external donors to fulfill their mandates. However, forecasting donations for long-term planning is an elusive task at best. The non-compulsory nature of donation requires NGOs to understand how donors’ attention and funding allocations change over time as conservation scenarios change and incorporate these insights into their budgeting plans. We hypothesize that an NGO can hinder its capacity to reach its conservation goals by neglecting its donor-NGO-natural system (DNNS), which is reactive to the socio-ecological context. To test our hypothesis, we compared the ecological outcomes derived from a budgeting strategy assuming donors have a fixed willingness to pay throughout the program (open-loop) against the reality that donor preferences change over time (closed-loop) based on the evolving ecological context, partly driven by the program’s actions. Our analysis was performed using two different willingness to pay (WTP) behavioural models, one representing donors informed about the success of the program supported (GPI), and another without such information (GPI), evidencing how the underlying assumptions about the target donors can radically change the organization’s fundraising strategy. Next, we used our closed-loop approach to estimate NGO’s optimal yearly donation requests to achieve a conservation target. Finally, we tested the consequences of presuming an incorrect WTP behavioural model while estimating optimal yearly donation requests by applying the optimization results from the previous step into a model parameterized with a different behavioural model. Our model was created by coupling a discrete choice experiment (DCE) and a systems dynamics model, developing a coupled social-ecological model of the eastern Monarch butterfly (Danaus plexippus), a charismatic long-distant migrant butterfly that has dwindled in numbers across North America mainly due to the increases in GMO agriculture. Our results showed a significant difference in donations received and ecological outcome forecasted by an open-loop model and the actual numbers obtained by the more real-life, closed-loop model, highlighting the importance of accounting for human behaviour during the planning phase of a long-term conservation strategy. Next, when we used our closed-loop to estimate optimal donation requests, the conservation objectives and funds raised were consistently and efficiently achieved, regardless of the underlying behavioural WTP model. We also designed novel visual tools from the behaviour WTP model exploration to bridge the gap between science insights obtained from DCEs and decision-making. However, when we used closed-loop optimal donation requests obtained from one WTP behaviour model into a simulation parameterized with different WTP behavioural models, considerable ecological and financial targets deviations arose. These deviations highlight the importance of acknowledging the dynamic nature of donor’s behaviour and the need to thoroughly characterize such behaviour. Finally, we introduce a novel forecasting tool that conservation managers will have at their disposal to improve the accuracy of their budget forecasting and, ultimately, increase the program’s success rate.
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9
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Greenstein L, Steele C, Taylor CM. Host plant specificity of the monarch butterfly Danaus plexippus: A systematic review and meta-analysis. PLoS One 2022; 17:e0269701. [PMID: 35700160 PMCID: PMC9197062 DOI: 10.1371/journal.pone.0269701] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2022] [Accepted: 05/25/2022] [Indexed: 11/26/2022] Open
Abstract
The preference-performance hypothesis explains host specificity in phytophagous insects, positing that host plants chosen by adults confer the greatest larval fitness. However, adults sometimes oviposit on plants supporting low larval success because the components of host specificity (adult preference, plant palatability, and larval survival) are non-binary and not necessarily correlated. Palatability (willingness to eat) is governed by chemical cues and physical barriers such as trichomes, while survival (ability to complete development) depends upon nutrition and toxicity. Absence of a correlation between the components of host specificity results in low-performance hosts supporting limited larval development. Most studies of specificity focus on oviposition behavior leaving the importance and basis of palatability and survival under-explored. We conducted a comprehensive review of 127 plant species that have been claimed or tested to be hosts for the monarch butterfly Danaus plexippus to classify them as non-hosts, low performance, or high performance. We performed a meta-analysis to test if performance status could be explained by properties of neurotoxic cardenolides or trichome density. We also conducted a no-choice larval feeding experiment to identify causes of low performance. We identified 34 high performance, 42 low performance, 33 non-hosts, and 18 species with unsubstantiated claims. Mean cardenolide concentration was greater in high- than low-performance hosts and a significant predictor of host status, suggesting possible evolutionary trade-offs in monarch specialization. Other cardenolide properties and trichome density were not significant predictors of host status. In the experiment, we found, of the 62% of larvae that attempted to eat low-performance hosts, only 3.5% survived to adult compared to 85% of those on the high-performance host, demonstrating that multiple factors affect larval host plant specificity. Our study is the first to classify all known host plants for monarchs and has conservation implications for this threatened species.
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Affiliation(s)
- Lewis Greenstein
- Illinois Natural History Survey, University of Illinois at Urbana-Champaign, Champaign, Illinois, United States of America
- Ecology and Evolutionary Biology, Tulane University, New Orleans, Louisiana, United States of America
- * E-mail:
| | - Christen Steele
- Ecology and Evolutionary Biology, Tulane University, New Orleans, Louisiana, United States of America
| | - Caz M. Taylor
- Ecology and Evolutionary Biology, Tulane University, New Orleans, Louisiana, United States of America
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10
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Spaeth KE, Barbour PJ, Moranz R, Dinsmore SJ, Williams CJ. Asclepias
dynamics on US rangelands: implications for conservation of monarch butterflies and other insects. Ecosphere 2022. [DOI: 10.1002/ecs2.3816] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Affiliation(s)
- Kenneth E. Spaeth
- USDA NRCS Central National Technology Center Fort Worth Texas 76115 USA
| | - Philip J. Barbour
- USDA NRCS Central National Technology Center Fort Worth Texas 76115 USA
| | - Ray Moranz
- The Xerces Society for Invertebrate Conservation/USDA NRCS Stillwater Oklahoma 74074 USA
| | - Stephen J. Dinsmore
- Department of Natural Resource Ecology and Management Iowa State University Ames Iowa 50014 USA
| | - C. Jason Williams
- USDA‐ARS Southwest Watershed Research Center Tucson Arizona 85719 USA
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11
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Pocius VM, Majewska AA, Freedman MG. The Role of Experiments in Monarch Butterfly Conservation: A Review of Recent Studies and Approaches. ANNALS OF THE ENTOMOLOGICAL SOCIETY OF AMERICA 2022; 115:10-24. [PMID: 35069967 PMCID: PMC8764570 DOI: 10.1093/aesa/saab036] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/07/2021] [Indexed: 06/14/2023]
Abstract
Monarch butterflies (Danaus plexippus) (Lepidoptera Danaidae Danaus plexippus (Linnaeus)) are an iconic species of conservation concern due to declines in the overwintering colonies over the past twenty years. Because of this downward trend in overwintering numbers in both California and Mexico, monarchs are currently considered 'warranted-but-precluded' for listing under the Endangered Species Act. Monarchs have a fascinating life history and have become a model system in chemical ecology, migration biology, and host-parasite interactions, but many aspects of monarch biology important for informing conservation practices remain unresolved. In this review, we focus on recent advances using experimental and genetic approaches that inform monarch conservation. In particular, we emphasize three areas of broad importance, which could have an immediate impact on monarch conservation efforts: 1) breeding habitat and host plant use, 2) natural enemies and exotic caterpillar food plants, and 3) the utility of genetic and genomic approaches for understanding monarch biology and informing ongoing conservation efforts. We also suggest future studies in these areas that could improve our understanding of monarch behavior and conservation.
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Affiliation(s)
- Victoria M Pocius
- Department of Biological Sciences, University of Alabama, Tuscaloosa, AL, USA
| | | | - Micah G Freedman
- Department of Ecology and Evolution, University of Chicago, Chicago, IL, USA
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12
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Carvajal Acosta AN, Mooney K. Effects of geographic variation in host plant resources for a specialist herbivore's contemporary and future distribution. Ecosphere 2021. [DOI: 10.1002/ecs2.3822] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Affiliation(s)
| | - Kailen Mooney
- Department of Ecology and Evolutionary Biology University of California Irvine California USA
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13
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Prouty C, Barriga P, Davis AK, Krischik V, Altizer S. Host Plant Species Mediates Impact of Neonicotinoid Exposure to Monarch Butterflies. INSECTS 2021; 12:insects12110999. [PMID: 34821799 PMCID: PMC8623494 DOI: 10.3390/insects12110999] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/12/2021] [Revised: 10/27/2021] [Accepted: 11/02/2021] [Indexed: 11/16/2022]
Abstract
Simple Summary Neonicotinoids are the most widely used insecticides in North America and many studies document the negative effects of neonicotinoids on bees. Monarch butterflies are famous for their long-distance migrations, and for their ability to sequester toxins from their milkweed host plants. The neonicotinoids imidacloprid and clothianidin were suggested to correlate with declines in North American monarchs. We examined how monarch development, survival, and flight were affected by exposure to neonicotinoids, and how these effects depend on milkweed host plant species that differ in their cardenolide toxins. Monarch survival and flight were unaffected by low and intermediate neonicotinoid doses. At the highest dose, neonicotinoids negatively affected monarch pupation and survival, for caterpillars that fed on the least toxic milkweed. Monarchs fed milkweed of intermediate toxicity experienced moderate negative effects of high insecticide doses. Monarchs fed the most toxic milkweed species had no negative consequences associated with neonicotinoid treatment. Our work shows that monarchs tolerate low neonicotinoid doses, but experience detrimental effects at higher doses, depending on milkweed species. To our knowledge, this is the first study to show that host plant species potentially reduce the residue of neonicotinoid insecticides on the leaf surface, and this phenomenon warrants further investigation. Abstract Neonicotinoids are the most widely used insecticides in North America. Numerous studies document the negative effects of neonicotinoids on bees, and it remains crucial to demonstrate if neonicotinoids affect other non-target insects, such as butterflies. Here we examine how two neonicotinoids (imidacloprid and clothianidin) affect the development, survival, and flight of monarch butterflies, and how these chemicals interact with the monarch’s milkweed host plant. We first fed caterpillars field-relevant low doses (0.075 and 0.225 ng/g) of neonicotinoids applied to milkweed leaves (Asclepias incarnata), and found no significant reductions in larval development rate, pre-adult survival, or adult flight performance. We next fed larvae higher neonicotinoid doses (4–70 ng/g) and reared them on milkweed species known to produce low, moderate, or high levels of secondary toxins (cardenolides). Monarchs exposed to the highest dose of clothianidin (51–70 ng/g) experienced pupal deformity, low survival to eclosion, smaller body size, and weaker adult grip strength. This effect was most evident for monarchs reared on the lowest cardenolide milkweed (A. incarnata), whereas monarchs reared on the high-cardenolide A. curassavica showed no significant reductions in any variable measured. Our results indicate that monarchs are tolerant to low doses of neonicotinoid, and that negative impacts of neonicotinoids depend on host plant type. Plant toxins may confer protective effects or leaf physical properties may affect chemical retention. Although neonicotinoid residues are ubiquitous on milkweeds in agricultural and ornamental settings, commonly encountered doses below 50 ng/g are unlikely to cause substantial declines in monarch survival or migratory performance.
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Affiliation(s)
- Cody Prouty
- Odum School of Ecology, University of Georgia, Athens, GA 30602, USA; (P.B.); (A.K.D.); (S.A.)
- Correspondence:
| | - Paola Barriga
- Odum School of Ecology, University of Georgia, Athens, GA 30602, USA; (P.B.); (A.K.D.); (S.A.)
| | - Andrew K. Davis
- Odum School of Ecology, University of Georgia, Athens, GA 30602, USA; (P.B.); (A.K.D.); (S.A.)
| | - Vera Krischik
- Department of Entomology, University of Minnesota, St. Paul, MN 55108, USA;
| | - Sonia Altizer
- Odum School of Ecology, University of Georgia, Athens, GA 30602, USA; (P.B.); (A.K.D.); (S.A.)
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14
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Kikuchi DW, Herberstein ME, Barfield M, Holt RD, Mappes J. Why aren't warning signals everywhere? On the prevalence of aposematism and mimicry in communities. Biol Rev Camb Philos Soc 2021; 96:2446-2460. [PMID: 34128583 DOI: 10.1111/brv.12760] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2020] [Revised: 05/27/2021] [Accepted: 06/01/2021] [Indexed: 11/29/2022]
Abstract
Warning signals are a striking example of natural selection present in almost every ecological community - from Nordic meadows to tropical rainforests, defended prey species and their mimics ward off potential predators before they attack. Yet despite the wide distribution of warning signals, they are relatively scarce as a proportion of the total prey available, and more so in some biomes than others. Classically, warning signals are thought to be governed by positive density-dependent selection, i.e. they succeed better when they are more common. Therefore, after surmounting this initial barrier to their evolution, it is puzzling that they remain uncommon on the scale of the community. Here, we explore factors likely to determine the prevalence of warning signals in prey assemblages. These factors include the nature of prey defences and any constraints upon them, the behavioural interactions of predators with different prey defences, the numerical responses of predators governed by movement and reproduction, the diversity and abundance of undefended alternative prey and Batesian mimics in the community, and variability in other ecological circumstances. We also discuss the macroevolution of warning signals. Our review finds that we have a basic understanding of how many species in some taxonomic groups have warning signals, but very little information on the interrelationships among population abundances across prey communities, the diversity of signal phenotypes, and prey defences. We also have detailed knowledge of how a few generalist predator species forage in artificial laboratory environments, but we know much less about how predators forage in complex natural communities with variable prey defences. We describe how empirical work to address each of these knowledge gaps can test specific hypotheses for why warning signals exhibit their particular patterns of distribution. This will help us to understand how behavioural interactions shape ecological communities.
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Affiliation(s)
- David W Kikuchi
- Wissenschaftskolleg zu Berlin, Wallotstraße 19, Berlin, Germany.,Evolutionary Biology, Universität Bielefeld, Konsequez 45, Bielefeld, 33615, Germany
| | - Marie E Herberstein
- Wissenschaftskolleg zu Berlin, Wallotstraße 19, Berlin, Germany.,Department of Biological Sciences, Macquarie University, North Ryde, New South Wales, 2109, Australia
| | - Michael Barfield
- Department of Biology, University of Florida, Gainesville, FL, 32611-8525, U.S.A
| | - Robert D Holt
- Department of Biology, University of Florida, Gainesville, FL, 32611-8525, U.S.A
| | - Johanna Mappes
- Wissenschaftskolleg zu Berlin, Wallotstraße 19, Berlin, Germany.,Organismal and Evolutionary Biology Research Programme, Faculty of Biological and Environmental Sciences, Helsinki University, Helsinki, Finland.,Department of Biological and Environmental Science, University of Jyväskylä, Jyväskylä, FI-40014, Finland
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15
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Griese E, Caarls L, Bassetti N, Mohammadin S, Verbaarschot P, Bukovinszkine’Kiss G, Poelman EH, Gols R, Schranz ME, Fatouros NE. Insect egg-killing: a new front on the evolutionary arms-race between brassicaceous plants and pierid butterflies. THE NEW PHYTOLOGIST 2021; 230:341-353. [PMID: 33305360 PMCID: PMC7986918 DOI: 10.1111/nph.17145] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/02/2020] [Accepted: 12/04/2020] [Indexed: 05/03/2023]
Abstract
Evolutionary arms-races between plants and insect herbivores have long been proposed to generate key innovations such as plant toxins and detoxification mechanisms that can drive diversification of the interacting species. A novel front-line of plant defence is the killing of herbivorous insect eggs. We test whether an egg-killing plant trait has an evolutionary basis in such a plant-insect arms-race. Within the crucifer family (Brassicaceae), some species express a hypersensitive response (HR)-like necrosis underneath butterfly eggs (Pieridae) that leads to eggs desiccating or falling off the plant. We studied the phylogenetic distribution of this trait, its egg-killing effect on and elicitation by butterflies, by screening 31 Brassicales species, and nine Pieridae species. We show a clade-specific induction of strong, egg-killing HR-like necrosis mainly in species of the Brassiceae tribe including Brassica crops and close relatives. The necrosis is strongly elicited by pierid butterflies that are specialists of crucifers. Furthermore, HR-like necrosis is linked to PR1 defence gene expression, accumulation of reactive oxygen species and cell death, eventually leading to egg-killing. Our findings suggest that the plants' egg-killing trait is a new front on the evolutionary arms-race between Brassicaceae and pierid butterflies beyond the well-studied plant toxins that have evolved against their caterpillars.
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Affiliation(s)
- Eddie Griese
- Biosystematics GroupWageningen UniversityWageningen6700 AAthe Netherlands
- Laboratory of EntomologyWageningen UniversityWageningen6700 AAthe Netherlands
| | - Lotte Caarls
- Biosystematics GroupWageningen UniversityWageningen6700 AAthe Netherlands
- Present address:
Plant BreedingWageningen University and ResearchWageningen6700 AJthe Netherlands
| | - Niccolò Bassetti
- Biosystematics GroupWageningen UniversityWageningen6700 AAthe Netherlands
| | - Setareh Mohammadin
- Biosystematics GroupWageningen UniversityWageningen6700 AAthe Netherlands
| | | | - Gabriella Bukovinszkine’Kiss
- Biosystematics GroupWageningen UniversityWageningen6700 AAthe Netherlands
- Laboratory of GeneticsWageningen UniversityWageningen6700 AAthe Netherlands
| | - Erik H. Poelman
- Laboratory of EntomologyWageningen UniversityWageningen6700 AAthe Netherlands
| | - Rieta Gols
- Laboratory of EntomologyWageningen UniversityWageningen6700 AAthe Netherlands
| | - M. Eric Schranz
- Biosystematics GroupWageningen UniversityWageningen6700 AAthe Netherlands
| | - Nina E. Fatouros
- Biosystematics GroupWageningen UniversityWageningen6700 AAthe Netherlands
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16
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Straub SCK, Boutte J, Fishbein M, Livshultz T. Enabling evolutionary studies at multiple scales in Apocynaceae through Hyb-Seq. APPLICATIONS IN PLANT SCIENCES 2020; 8:e11400. [PMID: 33304663 PMCID: PMC7705337 DOI: 10.1002/aps3.11400] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/01/2020] [Accepted: 09/12/2020] [Indexed: 05/07/2023]
Abstract
PREMISE Apocynaceae is the 10th largest flowering plant family and a focus for study of plant-insect interactions, especially as mediated by secondary metabolites. However, it has few genomic resources relative to its size. Target capture sequencing is a powerful approach for genome reduction that facilitates studies requiring data from the nuclear genome in non-model taxa, such as Apocynaceae. METHODS Transcriptomes were used to design probes for targeted sequencing of putatively single-copy nuclear genes across Apocynaceae. The sequences obtained were used to assess the success of the probe design, the intrageneric and intraspecific variation in the targeted genes, and the utility of the genes for inferring phylogeny. RESULTS From 853 candidate nuclear genes, 835 were consistently recovered in single copy and were variable enough for phylogenomics. The inferred gene trees were useful for coalescent-based species tree analysis, which showed all subfamilies of Apocynaceae as monophyletic, while also resolving relationships among species within the genus Apocynum. Intraspecific comparison of Elytropus chilensis individuals revealed numerous single-nucleotide polymorphisms with potential for use in population-level studies. DISCUSSION Community use of this Hyb-Seq probe set will facilitate and promote progress in the study of Apocynaceae across scales from population genomics to phylogenomics.
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Affiliation(s)
- Shannon C. K. Straub
- Department of BiologyHobart and William Smith Colleges300 Pulteney StreetGenevaNew York14456USA
| | - Julien Boutte
- Department of BiologyHobart and William Smith Colleges300 Pulteney StreetGenevaNew York14456USA
| | - Mark Fishbein
- Department of Plant Biology, Ecology, and EvolutionOklahoma State University301 Physical SciencesStillwaterOklahoma74078USA
| | - Tatyana Livshultz
- Department of Biodiversity, Earth, and Environmental Sciences and the Academy of Natural SciencesDrexel University1900 Benjamin Franklin ParkwayPhiladelphiaPennsylvania19103USA
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17
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Whitaker MRL, Salzman S. Ecology and evolution of cycad-feeding Lepidoptera. Ecol Lett 2020; 23:1862-1877. [PMID: 32969575 DOI: 10.1111/ele.13581] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2020] [Revised: 05/28/2020] [Accepted: 06/10/2020] [Indexed: 11/30/2022]
Abstract
Cycads are an ancient group of tropical gymnosperms that are toxic to most animals - including humans - though the larvae of many moths and butterflies (order: Lepidoptera) feed on cycads with apparent immunity. These insects belong to distinct lineages with varying degrees of specialisation and diverse feeding ecologies, presenting numerous opportunities for comparative studies of chemically mediated eco-evolutionary dynamics. This review presents the first evolutionary evaluation of cycad-feeding among Lepidoptera along with a comprehensive review of their ecology. Our analysis suggests that multiple lineages have independently colonised cycads from angiosperm hosts, yet only a few clades appear to have radiated following their transitions to cycads. Defensive traits are likely important for diversification, as many cycad specialists are warningly coloured and sequester cycad toxins. The butterfly family Lycaenidae appears to be particularly predisposed to cycad-feeding and several cycadivorous lycaenids are warningly coloured and chemically defended. Cycad-herbivore interactions provide a promising but underutilised study system for investigating plant-insect coevolution, convergent and divergent adaptations, and the multi-trophic significance of defensive traits; therefore the review ends by suggesting specific research gaps that would be fruitfully addressed in Lepidoptera and other cycad-feeding insects.
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Affiliation(s)
- Melissa R L Whitaker
- Entomological Collection, Department of Environmental Systems Science, ETH Zürich, Weinbergstrasse 56/58, Zürich, 8092, Switzerland.,Museum of Comparative Zoology, Department of Organismic and Evolutionary Biology, Harvard University, 26 Oxford Street, Cambridge, MA, 02138, USA
| | - Shayla Salzman
- Museum of Comparative Zoology, Department of Organismic and Evolutionary Biology, Harvard University, 26 Oxford Street, Cambridge, MA, 02138, USA.,School of Integrative Plant Science, Cornell University, 502 Mann Library, Ithaca, NY, 14853, USA
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18
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Abstract
Every fall, millions of North American monarch butterflies undergo a stunning long-distance migration to reach their overwintering grounds in Mexico. Migration allows the butterflies to escape freezing temperatures and dying host plants, and reduces infections with a virulent parasite. We discuss the multigenerational migration journey and its evolutionary history, and highlight the navigational mechanisms of migratory monarchs. Monarchs use a bidirectional time-compensated sun compass for orientation, which is based on a time-compensating circadian clock that resides in the antennae, and which has a distinctive molecular mechanism. Migrants can also use a light-dependent inclination magnetic compass for orientation under overcast conditions. Additional environmental features, e.g., atmospheric conditions, geologic barriers, and social interactions, likely augment navigation. The publication of the monarch genome and the development of gene-editing strategies have enabled the dissection of the genetic and neurobiological basis of the migration. The monarch butterfly has emerged as an excellent system to study the ecological, neural, and genetic basis of long-distance animal migration.
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Affiliation(s)
- Steven M Reppert
- Department of Neurobiology, University of Massachusetts Medical School, Worcester, MA 01605, USA.
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19
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Hermann SL, Blackledge C, Haan NL, Myers AT, Landis DA. Predators of monarch butterfly eggs and neonate larvae are more diverse than previously recognised. Sci Rep 2019; 9:14304. [PMID: 31586127 PMCID: PMC6778129 DOI: 10.1038/s41598-019-50737-5] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2019] [Accepted: 09/12/2019] [Indexed: 11/14/2022] Open
Abstract
Conserving threatened organisms requires knowledge of the factors impacting their populations. The Eastern monarch butterfly (Danaus plexippus L.) has declined by as much as 80% in the past two decades and conservation biologists are actively seeking to understand and reverse this decline. While it is well known that most monarchs die as eggs and young larvae, few studies have focused on identifying what arthropod taxa contribute to these losses. The aim of our study was to identify previously undocumented predators of immature monarchs in their summer breeding range in the United States. Using no-choice feeding assays augmented with field observations, we evaluated 75 arthropod taxa commonly found on the primary host plant for their propensity to consume immature monarchs. Here we report 36 previously unreported monarch predators, including representatives from 4 new orders (Orthoptera, Dermaptera, Lepidoptera and Opiliones) and 11 taxa (Acrididae, Gryllidae, Tettigoniidae, Forficulidae, Anthocoridae, Geocoridae, Lygaeidae, Miridae, Nabidae, Erebidae and Opilliones). Surprisingly, several putative herbivores were found to readily consume immature monarchs, both in a targeted fashion or incidentally as a result of herbivory. This work expands our understanding of the monarch predator community and highlights the importance of unrecognized predation on insects of conservation concern.
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Affiliation(s)
- Sara L Hermann
- Department of Entomology, The Pennsylvania State University, University Park, USA.
| | | | - Nathan L Haan
- Department of Entomology, Michigan State University, East Lansing, USA
| | - Andrew T Myers
- Department of Entomology, Michigan State University, East Lansing, USA.,Program in Ecology, Evolutionary Biology and Behavior, Michigan State University, East Lansing, USA
| | - Douglas A Landis
- Department of Entomology, Michigan State University, East Lansing, USA.,Program in Ecology, Evolutionary Biology and Behavior, Michigan State University, East Lansing, USA
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20
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Exposure to Non-Native Tropical Milkweed Promotes Reproductive Development in Migratory Monarch Butterflies. INSECTS 2019; 10:insects10080253. [PMID: 31426310 PMCID: PMC6724006 DOI: 10.3390/insects10080253] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/22/2019] [Revised: 07/22/2019] [Accepted: 08/12/2019] [Indexed: 11/16/2022]
Abstract
Background: North American monarchs (Danaus plexippus) are well-known for their long-distance migrations; however, some monarchs within the migratory range have adopted a resident lifestyle and breed year-round at sites where tropical milkweed (Asclepias curassavica) is planted in the southern coastal United States. An important question is whether exposure to exotic milkweed alters monarch migratory physiology, particularly the ability to enter and remain in the hormonally-induced state of reproductive diapause, whereby adults delay reproductive maturity. Cued by cooler temperatures and shorter photoperiods, diapause is a component of the monarch’s migratory syndrome that includes directional flight behavior, lipid accumulation, and the exceptional longevity of the migratory generation. Methods: Here, we experimentally test how exposure to tropical milkweed during the larval and adult stages influences monarch reproductive status during fall migration. Caterpillars reared under fall-like conditions were fed tropical versus native milkweed diets, and wild adult migrants were placed in outdoor flight cages with tropical milkweed, native milkweed, or no milkweed. Results: We found that monarchs exposed to tropical milkweed as larvae were more likely to be reproductively active (exhibit mating behavior in males and develop mature eggs in females) compared to monarchs exposed to native milkweed. Among wild-caught fall migrants, females exposed to tropical milkweed showed greater egg development than females exposed to native or no milkweed, although a similar response was not observed for males. Conclusions: Our study provides evidence that exposure to tropical milkweed can increase monarch reproductive activity, which could promote continued residency at year-round breeding sites and decrease monarch migratory propensity.
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21
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Dee JR, Baum KA. Mowing Frequency Influences Number of Flowering Stems but not Population Age Structure of Asclepias viridis, an Important Monarch Host Plant. AMERICAN MIDLAND NATURALIST 2019. [DOI: 10.1674/0003-0031-182.1.27] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Affiliation(s)
- Justin R. Dee
- Department of Plant Biology, Ecology, and Evolution, Oklahoma State University, Stillwater 74078
| | - Kristen A. Baum
- Department of Integrative Biology, Oklahoma State University, Stillwater 74078
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22
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Oberhauser KS, Alonso A, Malcolm SB, Williams EH, Zalucki MP. Lincoln Brower, Champion for Monarchs. Front Ecol Evol 2019. [DOI: 10.3389/fevo.2019.00149] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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23
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Jones PL, Agrawal AA. Beyond preference and performance: host plant selection by monarch butterflies,
Danaus plexippus. OIKOS 2019. [DOI: 10.1111/oik.06001] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
| | - Anurag A. Agrawal
- Dept of Ecology and Evolutionary Biology, Cornell Univ Ithaca NY USA
- Dept of Entomology, Cornell Univ Ithaca NY USA
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24
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Decker LE, Soule AJ, de Roode JC, Hunter MD. Phytochemical changes in milkweed induced by elevated CO
2
alter wing morphology but not toxin sequestration in monarch butterflies. Funct Ecol 2019. [DOI: 10.1111/1365-2435.13270] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Affiliation(s)
- Leslie E. Decker
- Department of Biology Stanford University Stanford California
- Department of Ecology and Evolutionary Biology University of Michigan Ann Arbor Michigan
| | - Abrianna J. Soule
- Department of Ecology and Evolutionary Biology University of Michigan Ann Arbor Michigan
- Department of Biology University of Utah Salt Lake City Utah
| | | | - Mark D. Hunter
- Department of Ecology and Evolutionary Biology University of Michigan Ann Arbor Michigan
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25
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Ricono A, Dixon R, Eaton I, Brightbill CM, Yaziji Y, Puzey JR, Dalgleish HJ. Long- and short-term responses of Asclepias species differ in respect to fire, grazing, and nutrient addition. AMERICAN JOURNAL OF BOTANY 2018; 105:2008-2017. [PMID: 30485407 DOI: 10.1002/ajb2.1197] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/24/2018] [Accepted: 08/29/2018] [Indexed: 06/09/2023]
Abstract
PREMISE OF THE STUDY The tallgrass prairie ecosystem has experienced a dramatic reduction over the past 150 yr. This reduction has impacted the abundance of native grassland species, including milkweeds (Asclepias). METHODS We used two long-term (27 yr) data sets to examine how fire, grazing, and nutrient addition shape milkweed abundance in tallgrass prairie. We compared these results to those of a greenhouse experiment that varied nutrient levels in the absence of competition, herbivory, and mutualistic relationships. KEY RESULTS Asclepias species exhibited broad patterns in response to burning regimes that did not include grazing, but experienced more species-specific patterns in other combinations. Asclepias syriaca was the only species to increase in abundance in plots that included burning and nutrient addition. In the greenhouse we found that nitrogen significantly increased biomass, while no effect of phosphorus was detected. CONCLUSIONS These results indicate that A. syriaca will do best in settings with high nutrient loads, low competition, and no grazers. These characteristics define a small portion of the tallgrass prairie but exemplify modern agricultural settings, which have replaced prairies. However, other milkweeds examined did not share this pattern, which indicates that milkweed species will respond differently when exposed to agricultural settings, with some less able to cope with land conversion to pasture or row-crop agriculture.
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Affiliation(s)
- Angela Ricono
- Department of Biology, College of William and Mary, Williamsburg, Virginia, 23185, USA
| | - Robin Dixon
- Department of Biology, College of William and Mary, Williamsburg, Virginia, 23185, USA
| | - Isabel Eaton
- Department of Biology, College of William and Mary, Williamsburg, Virginia, 23185, USA
| | - Caroline M Brightbill
- Department of Biology, College of William and Mary, Williamsburg, Virginia, 23185, USA
| | - Yahya Yaziji
- Department of Biology, College of William and Mary, Williamsburg, Virginia, 23185, USA
| | - Joshua R Puzey
- Department of Biology, College of William and Mary, Williamsburg, Virginia, 23185, USA
| | - Harmony J Dalgleish
- Department of Biology, College of William and Mary, Williamsburg, Virginia, 23185, USA
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26
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Decker LE, de Roode JC, Hunter MD. Elevated atmospheric concentrations of carbon dioxide reduce monarch tolerance and increase parasite virulence by altering the medicinal properties of milkweeds. Ecol Lett 2018; 21:1353-1363. [PMID: 30134036 DOI: 10.1111/ele.13101] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2018] [Revised: 03/28/2018] [Accepted: 05/16/2018] [Indexed: 12/13/2022]
Abstract
Hosts combat their parasites using mechanisms of resistance and tolerance, which together determine parasite virulence. Environmental factors, including diet, mediate the impact of parasites on hosts, with diet providing nutritional and medicinal properties. Here, we present the first evidence that ongoing environmental change decreases host tolerance and increases parasite virulence through a loss of dietary medicinal quality. Monarch butterflies use dietary toxins (cardenolides) to reduce the deleterious impacts of a protozoan parasite. We fed monarch larvae foliage from four milkweed species grown under either elevated or ambient CO2 , and measured changes in resistance, tolerance, and virulence. The most high-cardenolide milkweed species lost its medicinal properties under elevated CO2 ; monarch tolerance to infection decreased, and parasite virulence increased. Declines in medicinal quality were associated with declines in foliar concentrations of lipophilic cardenolides. Our results emphasize that global environmental change may influence parasite-host interactions through changes in the medicinal properties of plants.
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Affiliation(s)
- Leslie E Decker
- Department of Ecology and Evolutionary Biology, University of Michigan, Biological Sciences Building, 1105 North University Avenue, Ann Arbor, MI, 48109-1085, USA
| | - Jacobus C de Roode
- Biology Department, Rollins 1113 O. Wayne Rollins Research Center, Emory University, 1510 Clifton Road, Atlanta, GA, 30322, USA
| | - Mark D Hunter
- Department of Ecology and Evolutionary Biology, University of Michigan, Biological Sciences Building, 1105 North University Avenue, Ann Arbor, MI, 48109-1085, USA
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27
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Meier AR, Hunter MD. Mycorrhizae Alter Toxin Sequestration and Performance of Two Specialist Herbivores. Front Ecol Evol 2018. [DOI: 10.3389/fevo.2018.00033] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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28
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Coevolution takes the sting out of it: Evolutionary biology and mechanisms of toxin resistance in animals. Toxicon 2017; 140:118-131. [DOI: 10.1016/j.toxicon.2017.10.026] [Citation(s) in RCA: 51] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2017] [Revised: 10/06/2017] [Accepted: 10/23/2017] [Indexed: 01/09/2023]
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29
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Adesanya AW, Held DW, Liu N. Geranium intoxication induces detoxification enzymes in the Japanese beetle, Popillia japonica Newman. PESTICIDE BIOCHEMISTRY AND PHYSIOLOGY 2017; 143:1-7. [PMID: 29183576 DOI: 10.1016/j.pestbp.2017.07.008] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/20/2017] [Revised: 07/25/2017] [Accepted: 07/28/2017] [Indexed: 06/07/2023]
Abstract
Popillia japonica is a generalist herbivore that feeds on >300 host plant species in at least 72 plant families. It is unknown why P. japonica, despite possessing active detoxification enzymes in its gut, is paralyzed when feeding on the petals of one of its preferred host plant, Pelargonium×hortorum, or on artificial diet containing quisqualic acid (QA), the active compound in zonal geranium. We hypothesized that Pelargonium×hortorum or QA do not induce activity of the cytochrome P450, glutathione S transferase (GST), and carboxylesterase (CoE) detoxification enzymes in P. japonica. In this study, P. japonica were fed petals of zonal geranium or agar plugs containing QA, or rose petals, another preferred but non-toxic host. Midgut enzyme activities of P450, GST, and CoE were then assayed after 6, 12, or 24h of feeding. In most cases, P450, GST, and CoE activities were significantly induced in P. japonica midguts by geranium petals and QA, though the induction was slower than with rose petals. Induced enzyme activity reached a peak at 24h after consumption, which coincides with the period of highest recovery from geranium and QA paralysis. This study shows that toxic geranium and QA induce detoxification enzyme activity, but the induced enzymes do not effectively protect P. japonica from paralysis by QA. Further investigation is required through in vitro studies to know if the enzymes induced by geranium are capable of metabolizing QA. This study highlights a rare physiological mismatch between the detoxification tool kit of a generalist and its preferred host.
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Affiliation(s)
- Adekunle W Adesanya
- Department of Entomology and Plant Pathology, Auburn University, 301 Funchess Hall, Auburn, AL 36830, United States; Department of Entomology, Washington State University, 279A FSHN building, Pullman, WA 99163, United States.
| | - David W Held
- Department of Entomology and Plant Pathology, Auburn University, 301 Funchess Hall, Auburn, AL 36830, United States.
| | - Nannan Liu
- Department of Entomology and Plant Pathology, Auburn University, 301 Funchess Hall, Auburn, AL 36830, United States
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30
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Mebs D, Wunder C, Toennes SW. Poor sequestration of toxic host plant cardenolides and their rapid loss in the milkweed butterfly Danaus chrysippus (Lepidoptera: Nymphalidae: Danainae: Danaini). Toxicon 2017; 131:1-5. [PMID: 28284846 DOI: 10.1016/j.toxicon.2017.03.006] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2016] [Revised: 03/01/2017] [Accepted: 03/06/2017] [Indexed: 11/29/2022]
Abstract
Butterflies of the genus Danaus are known to sequester toxic cardenolides from milkweed host plants (Apocynaceae). In particular, Danaus plexippus efficiently sequesters and stores these compounds, whereas D. chrysippus, is considered to poorly sequester cardenolides. To estimate its sequestration capability compared with that of D. plexippus, larvae of both species were jointly reared on Asclepias curassavica and the major cardenolides of the host plant, calotropin and calactin, were analyzed in adults sampled at different time intervals after eclosion. Both cardenolides were detected in body and wings of D. plexippus. Whereas the calotropin-concentration remained constant over a period of 24 days, that of calactin steadily decreased. In the body, but not in the wings of D. chrysippus, calactin only was detected in low amounts, which was then almost completely lost during the following 8 days after eclosion, suggesting that in contrast to D. plexippus, cardenolides seem to be less important for that butterfly's defence against predators.
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Affiliation(s)
- Dietrich Mebs
- Institute of Legal Medicine, University of Frankfurt, Kennedyallee 104, D-60596, Frankfurt, Germany.
| | - Cora Wunder
- Institute of Legal Medicine, University of Frankfurt, Kennedyallee 104, D-60596, Frankfurt, Germany
| | - Stefan W Toennes
- Institute of Legal Medicine, University of Frankfurt, Kennedyallee 104, D-60596, Frankfurt, Germany
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31
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McKay AF, Ezenwa VO, Altizer S. Consequences of Food Restriction for Immune Defense, Parasite Infection, and Fitness in Monarch Butterflies. Physiol Biochem Zool 2016; 89:389-401. [DOI: 10.1086/687989] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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Petschenka G, Agrawal AA. Milkweed butterfly resistance to plant toxins is linked to sequestration, not coping with a toxic diet. Proc Biol Sci 2016; 282:20151865. [PMID: 26538594 DOI: 10.1098/rspb.2015.1865] [Citation(s) in RCA: 62] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Insect resistance to plant toxins is widely assumed to have evolved in response to using defended plants as a dietary resource. We tested this hypothesis in the milkweed butterflies (Danaini) which have progressively evolved higher levels of resistance to cardenolide toxins based on amino acid substitutions of their cellular sodium-potassium pump (Na(+)/K(+)-ATPase). Using chemical, physiological and caterpillar growth assays on diverse milkweeds (Asclepias spp.) and isolated cardenolides, we show that resistant Na(+)/K(+)-ATPases are not necessary to cope with dietary cardenolides. By contrast, sequestration of cardenolides in the body (as a defence against predators) is associated with the three levels of Na(+)/K(+)-ATPase resistance. To estimate the potential physiological burden of cardenolide sequestration without Na(+)/K(+)-ATPase adaptations, we applied haemolymph of sequestering species on isolated Na(+)/K(+)-ATPase of sequestering and non-sequestering species. Haemolymph cardenolides dramatically impair non-adapted Na(+)/K(+)-ATPase, but had systematically reduced effects on Na(+)/K(+)-ATPase of sequestering species. Our data indicate that major adaptations to plant toxins may be evolutionarily linked to sequestration, and may not necessarily be a means to eat toxic plants. Na(+)/K(+)-ATPase adaptations thus were a potential mechanism through which predators spurred the coevolutionary arms race between plants and insects.
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Affiliation(s)
- Georg Petschenka
- Department of Ecology and Evolutionary Biology, Cornell University, Ithaca, NY 14853, USA
| | - Anurag A Agrawal
- Department of Ecology and Evolutionary Biology, Cornell University, Ithaca, NY 14853, USA
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33
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Ali JG, Agrawal AA. Trade‐offs and tritrophic consequences of host shifts in specialized root herbivores. Funct Ecol 2016. [DOI: 10.1111/1365-2435.12698] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Jared G. Ali
- Department of Entomology The Pennsylvania State University University Park PA 16802 USA
| | - Anurag A. Agrawal
- Department of Ecology and Evolutionary Biology Cornell University Ithaca NY 14853 USA
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Katsanis A, Rasmann S, Mooney KA. Herbivore Diet Breadth and Host Plant Defense Mediate the Tri-Trophic Effects of Plant Toxins on Multiple Coccinellid Predators. PLoS One 2016; 11:e0155716. [PMID: 27182598 PMCID: PMC4868332 DOI: 10.1371/journal.pone.0155716] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2015] [Accepted: 05/03/2016] [Indexed: 12/04/2022] Open
Abstract
Host plant defenses are known to cascade up food chains to influence herbivores and their natural enemies, but how herbivore and predator traits and identity mediate such tri-trophic dynamics is largely unknown. We assessed the influence of plant defense on aphid and coccinellid performance in laboratory trials with low- vs. high-glucosinolate varieties of Brassica napus, a dietary specialist (Brevicoryne brassicae) and generalist (Myzus persicae) aphid, and five species of aphidophagous coccinellids. The performance of the specialist and generalist aphids was similar and unaffected by variation in plant defense. Aphid glucosinolate concentration and resistance to predators differed by aphid species and host plant defense, and these effects acted independently. With respect to aphid species, the dietary generalist aphid (vs. specialist) had 14% lower glucosinolate concentration and coccinellid predators ate three-fold more aphids. With respect to host plant variety, the high-glucosinolate plants (vs. low) increased aphid glucosinolate concentration by 21%, but had relatively weak effects on predation by coccinellids and these effects varied among coccinellid species. In turn, coccinellid performance was influenced by the interactive effects of plant defense and aphid species, as the cascading, indirect effect of plant defense was greater when feeding upon the specialist than generalist aphid. When feeding upon specialist aphids, low- (vs. high-) glucosinolate plants increased coccinellid mass gain by 78% and accelerated development by 14%. In contrast, when feeding upon generalist aphids, low- (vs. high-) glucosinolate plants increased coccinellid mass gain by only 11% and had no detectable effect on development time. These interactive effects of plant defense and aphid diet breadth on predator performance also varied among coccinellid species; the indirect negative effects of plant defenses on predator performance was consistent among the five predators when transmitted via the dietary specialist aphid, but these effects varied substantially among predators—in both the magnitude and direction—when transmitted via the dietary generalist aphid. Accordingly, the cascading effect of plant defense on predators was stronger in magnitude and more consistent among predator taxa when transmitted by the specialist than generalist herbivore. Overall, these findings support a central role of herbivore diet breadth in mediating both the strength and contingency of tri-trophic interactions.
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Affiliation(s)
- Angelos Katsanis
- Department of Ecology and Evolutionary Biology, University of California Irvine, 321 Steinhaus Hall, Irvine, California, United States of America
- * E-mail:
| | - Sergio Rasmann
- Department of Ecology and Evolutionary Biology, University of California Irvine, 321 Steinhaus Hall, Irvine, California, United States of America
| | - Kailen A. Mooney
- Department of Ecology and Evolutionary Biology, University of California Irvine, 321 Steinhaus Hall, Irvine, California, United States of America
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35
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Poyet M, Le Roux V, Gibert P, Meirland A, Prévost G, Eslin P, Chabrerie O. The Wide Potential Trophic Niche of the Asiatic Fruit Fly Drosophila suzukii: The Key of Its Invasion Success in Temperate Europe? PLoS One 2015; 10:e0142785. [PMID: 26581101 PMCID: PMC4651357 DOI: 10.1371/journal.pone.0142785] [Citation(s) in RCA: 90] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2015] [Accepted: 10/27/2015] [Indexed: 11/19/2022] Open
Abstract
The Asiatic fruit fly Drosophila suzukii has recently invaded Europe and North and South America, causing severe damage to fruit production systems. Although agronomic host plants of that fly are now well documented, little is known about the suitability of wild and ornamental hosts in its exotic area. In order to study the potential trophic niche of D. suzukii with relation to fruit characteristics, fleshy fruits from 67 plant species were sampled in natural and anthropic ecosystems (forests, hedgerows, grasslands, coastal areas, gardens and urban areas) of the north of France and submitted to experimental infestations. A set of fruit traits (structure, colour, shape, skin texture, diameter and weight, phenology) potentially interacting with oviposition choices and development success of D. suzukii was measured. Almost half of the tested plant species belonging to 17 plant families allowed the full development of D. suzukii. This suggests that the extreme polyphagy of the fly and the very large reservoir of hosts producing fruits all year round ensure temporal continuity in resource availability and contribute to the persistence and the exceptional invasion success of D. suzukii in natural habitats and neighbouring cultivated systems. Nevertheless, this very plastic trophic niche is not systematically beneficial to the fly. Some of the tested plants attractive to D. suzukii gravid females stimulate oviposition but do not allow full larval development. Planted near sensitive crops, these "trap plants" may attract and lure D. suzukii, therefore contributing to the control of the invasive fly.
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Affiliation(s)
- Mathilde Poyet
- Unité Ecologie et Dynamiques des Systèmes Anthropisés (FRE-CNRS 3498), Université de Picardie Jules Verne, Amiens, France
- Laboratoire de Biométrie et Biologie Evolutive (UMR-CNRS 5558), Université Claude Bernard Lyon 1, Villeurbanne, France
| | - Vincent Le Roux
- Unité Ecologie et Dynamiques des Systèmes Anthropisés (FRE-CNRS 3498), Université de Picardie Jules Verne, Amiens, France
| | - Patricia Gibert
- Laboratoire de Biométrie et Biologie Evolutive (UMR-CNRS 5558), Université Claude Bernard Lyon 1, Villeurbanne, France
| | - Antoine Meirland
- Unité Ecologie et Dynamiques des Systèmes Anthropisés (FRE-CNRS 3498), Université de Picardie Jules Verne, Amiens, France
- Groupe d'étude des milieux estuariens et littoraux (GEMEL) Picardie, Maison de l’Université de Picardie Jules Verne, Saint Valery-Sur-Somme, France
| | - Geneviève Prévost
- Unité Ecologie et Dynamiques des Systèmes Anthropisés (FRE-CNRS 3498), Université de Picardie Jules Verne, Amiens, France
| | - Patrice Eslin
- Unité Ecologie et Dynamiques des Systèmes Anthropisés (FRE-CNRS 3498), Université de Picardie Jules Verne, Amiens, France
| | - Olivier Chabrerie
- Unité Ecologie et Dynamiques des Systèmes Anthropisés (FRE-CNRS 3498), Université de Picardie Jules Verne, Amiens, France
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36
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Marion ZH, Fordyce JA, Fitzpatrick BM. Extending the Concept of Diversity Partitioning to Characterize Phenotypic Complexity. Am Nat 2015; 186:348-61. [PMID: 26655353 DOI: 10.1086/682369] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
Most components of an organism's phenotype can be viewed as the expression of multiple traits. Many of these traits operate as complexes, where multiple subsidiary parts function and evolve together. As trait complexity increases, so does the challenge of describing complexity in intuitive, biologically meaningful ways. Traditional multivariate analyses ignore the phenomenon of individual complexity and provide relatively abstract representations of variation among individuals. We suggest adopting well-known diversity indices from community ecology to describe phenotypic complexity as the diversity of distinct subsidiary components of a trait. Using a hierarchical framework, we illustrate how total trait diversity can be partitioned into within-individual complexity (α diversity) and between-individual components (β diversity). This approach complements traditional multivariate analyses. The key innovations are (i) addition of individual complexity within the same framework as between-individual variation and (ii) a group-wise partitioning approach that complements traditional level-wise partitioning of diversity. The complexity-as-diversity approach has potential application in many fields, including physiological ecology, ecological and community genomics, and transcriptomics. We demonstrate the utility of this complexity-as-diversity approach with examples from chemical and microbial ecology. The examples illustrate biologically significant differences in complexity and diversity that standard analyses would not reveal.
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Affiliation(s)
- Zachary H Marion
- Department of Ecology and Evolutionary Biology, University of Tennessee, Knoxville, Tennessee, 37996
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37
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Kojima Y, Mori A. Active foraging for toxic prey during gestation in a snake with maternal provisioning of sequestered chemical defences. Proc Biol Sci 2015; 282:20142137. [PMID: 25392472 DOI: 10.1098/rspb.2014.2137] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
Many animals sequester dietary defensive compounds and incorporate them into the offspring, which protects the young against predation. One possible but poorly investigated question is whether females of such species actively prey upon toxic diets. The snake Rhabdophis tigrinus sequesters defensive steroids from toads consumed as prey; it also feeds on other amphibians. Females produce chemically armed offspring in direct proportion to their own level of toad-derived toxins by provisioning the toxins to their eggs. Our field observations of movements and stomach contents of radio-tracked R. tigrinus showed that gravid snakes preyed upon toads by actively foraging in the habitat of toads, even though toads were a scarce resource and toad-searching may incur potential costs. Our Y-maze experiments demonstrated that gravid females were more likely to trail the chemical cues of toads than were males or non-gravid females. These results showed behavioural switching in females and active foraging for scarce, toxic prey during gestation. Because exploitation of toads by gravid females results in their offspring being more richly endowed with prey-derived toxins, active foraging for toxic prey is expected to be an adaptive antipredator trait, which may enhance chemical defence in offspring.
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Affiliation(s)
- Yosuke Kojima
- Department of Zoology, Graduate School of Science, Kyoto University, Sakyo, Kyoto 606-8502, Japan
| | - Akira Mori
- Department of Zoology, Graduate School of Science, Kyoto University, Sakyo, Kyoto 606-8502, Japan
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38
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Barnett CA, Bateson M, Rowe C. Better the devil you know: avian predators find variation in prey toxicity aversive. Biol Lett 2015; 10:20140533. [PMID: 25392317 DOI: 10.1098/rsbl.2014.0533] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Toxic prey that signal their defences to predators using conspicuous warning signals are called 'aposematic'. Predators learn about the toxic content of aposematic prey and reduce their attacks on them. However, through regulating their toxin intake, predators will include aposematic prey in their diets when the benefits of gaining the nutrients they contain outweigh the costs of ingesting the prey's toxins. Predators face a problem when managing their toxin intake: prey sharing the same warning signal often vary in their toxicities. Given that predators should avoid uncertainty when managing their toxin intake, we tested whether European starlings (Sturnus vulgaris) preferred to eat fixed-defence prey (where all prey contained a 2% quinine solution) to mixed-defence prey (where half the prey contained a 4% quinine solution and the other half contained only water). Our results support the idea that predators should be more 'risk-averse' when foraging on variably defended prey and suggest that variation in toxicity levels could be a form of defence.
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Affiliation(s)
- Craig A Barnett
- Centre for Behaviour and Evolution, Institute of Neuroscience, Newcastle University, Newcastle upon Tyne NE2 4HH, UK
| | - Melissa Bateson
- Centre for Behaviour and Evolution, Institute of Neuroscience, Newcastle University, Newcastle upon Tyne NE2 4HH, UK
| | - Candy Rowe
- Centre for Behaviour and Evolution, Institute of Neuroscience, Newcastle University, Newcastle upon Tyne NE2 4HH, UK
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39
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Lange BM. The evolution of plant secretory structures and emergence of terpenoid chemical diversity. ANNUAL REVIEW OF PLANT BIOLOGY 2015; 66:139-59. [PMID: 25621517 DOI: 10.1146/annurev-arplant-043014-114639] [Citation(s) in RCA: 93] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
Secretory structures in terrestrial plants appear to have first emerged as intracellular oil bodies in liverworts. In vascular plants, internal secretory structures, such as resin ducts and laticifers, are usually found in conjunction with vascular bundles, whereas subepidermal secretory cavities and epidermal glandular trichomes generally have more complex tissue distribution patterns. The primary function of plant secretory structures is related to defense responses, both constitutive and induced, against herbivores and pathogens. The ability to sequester secondary (or specialized) metabolites and defense proteins in secretory structures was a critical adaptation that shaped plant-herbivore and plant-pathogen interactions. Although this review places particular emphasis on describing the evolution of pathways leading to terpenoids, it also assesses the emergence of other metabolite classes to outline the metabolic capabilities of different plant lineages.
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Affiliation(s)
- Bernd Markus Lange
- Institute of Biological Chemistry and M.J. Murdock Metabolomics Laboratory, Washington State University, Pullman, Washington 99164-6340;
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40
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Sternberg ED, de Roode JC, Hunter MD. Trans-generational parasite protection associated with paternal diet. J Anim Ecol 2014; 84:310-21. [PMID: 25251734 DOI: 10.1111/1365-2656.12289] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2014] [Accepted: 09/19/2014] [Indexed: 11/29/2022]
Abstract
Multiple generations of hosts are often exposed to the same pathogens, favouring the evolution of trans-generational defences. Because females have more opportunities to transfer protective molecules to offspring, many studies have focused on maternally derived protection. However, males of many species can transfer compounds along with sperm, including chemicals that could provide protection. Here, we assess maternally and paternally derived protection in a monarch butterfly-protozoan parasite system where parasite resistance is heavily influenced by secondary plant chemicals, known as cardenolides, present in the larval diet of milkweed plants. We reared monarch butterflies on medicinal and non-medicinal milkweed species and then measured resistance of their offspring to infection. We also measured cardenolide content in adult monarchs reared on the two species, and in the eggs that they produced. We found that offspring were more resistant to infection when their fathers were reared on medicinal milkweed, while maternal diet had less of an effect. We also found that eggs contained the highest levels of cardenolides when both parents were reared on the medicinal species. Moreover, females reared on non-medicinal milkweed produced eggs with significantly higher levels of cardenolides if they mated with males reared on the medicinal milkweed species. However, we found an equivocal relationship between the cardenolides present in eggs and parasite resistance in the offspring. Our results demonstrate that males reared on medicinal plants can transfer protection to their offspring, but the exact mechanism remains unresolved. This suggests that paternal protection from parasitism might be important, particularly when there are environmental sources of parasite resistance and when males transfer spermatophores during mating.
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Affiliation(s)
- Eleanore D Sternberg
- Department of Biology, Emory University, 1510 Clifton Road, Atlanta, GA, 30322, USA.,Center for Infectious Disease Dynamics, Pennsylvania State University, 111 Merkle Building, University Park, PA, 16802, USA
| | - Jacobus C de Roode
- Department of Biology, Emory University, 1510 Clifton Road, Atlanta, GA, 30322, USA
| | - Mark D Hunter
- Department of Ecology and Evolutionary Biology, University of Michigan, 2053 Natural Sciences Building, 830 North University, Ann Arbor, MI, 48109-1048, USA
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41
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Speed MP, Franks DW. Antagonistic evolution in an aposematic predator-prey signaling system. Evolution 2014; 68:2996-3007. [PMID: 25132560 DOI: 10.1111/evo.12498] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2013] [Accepted: 07/02/2014] [Indexed: 11/29/2022]
Abstract
Warning signals within species, such as the bright colors of chemically defended animals, are usually considered mutualistic, monomorphic traits. Such a view is however increasingly at odds with the growing empirical literature, showing nontrivial levels of signal variation within prey populations. Key to understanding this variation, we argue, could be a recognition that toxicity levels frequently vary within populations because of environmental heterogeneity. Inequalities in defense may undermine mutualistic monomorphic signaling, causing evolutionary antagonism between loci that determine appearance of less well-defended and better defended prey forms within species. In this article, we apply a stochastic model of evolved phenotypic plasticity to the evolution of prey signals. We show that when toxicity levels vary, then antagonistic interactions can lead to evolutionary conflict between alleles at different signaling loci, causing signal evolution, "red queen-like" evolutionary chase, and one or more forms of signaling equilibria. A key prediction is that variation in the way that predators use information about toxicity levels in their attack behaviors profoundly affects the evolutionary characteristics of the prey signaling systems. Environmental variation is known to cause variation in many qualities that organisms signal; our approach may therefore have application to other signaling systems.
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Affiliation(s)
- Michael P Speed
- Department of Evolution, Ecology and Behaviour, Institute of Integrative Biology, Faculty of Health and Life Sciences, University of Liverpool, Liverpool L69 7ZB, United Kingdom.
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42
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Development of a generalist predator, Podisus maculiventris, on glucosinolate sequestering and nonsequestering prey. Naturwissenschaften 2014; 101:707-14. [DOI: 10.1007/s00114-014-1207-x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2014] [Revised: 06/18/2014] [Accepted: 06/26/2014] [Indexed: 10/25/2022]
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43
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Choisy M, de Roode JC. The ecology and evolution of animal medication: genetically fixed response versus phenotypic plasticity. Am Nat 2014; 184 Suppl 1:S31-46. [PMID: 25061676 DOI: 10.1086/676928] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
Animal medication against parasites can occur either as a genetically fixed (constitutive) or phenotypically plastic (induced) behavior. Taking the tritrophic interaction between the monarch butterfly Danaus plexippus, its protozoan parasite Ophryocystis elektroscirrha, and its food plant Asclepias spp. as a test case, we develop a game-theory model to identify the epidemiological (parasite prevalence and virulence) and environmental (plant toxicity and abundance) conditions that predict the evolution of genetically fixed versus phenotypically plastic forms of medication. Our model shows that the relative benefits (the antiparasitic properties of medicinal food) and costs (side effects of medicine, the costs of searching for medicine, and the costs of plasticity itself) crucially determine whether medication is genetically fixed or phenotypically plastic. Our model suggests that animals evolve phenotypic plasticity when parasite risk (a combination of virulence and prevalence and thus a measure of the strength of parasite-mediated selection) is relatively low to moderately high and genetically fixed medication when parasite risk becomes very high. The latter occurs because at high parasite risk, the costs of plasticity are outweighed by the benefits of medication. Our model provides a simple and general framework to study the conditions that drive the evolution of alternative forms of animal medication.
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Affiliation(s)
- Marc Choisy
- Maladies Infectieuses et Vecteurs: Ecologie, Génétique, Evolution et Contrôle (MIVEGEC; CNRS 5290, Institut de Recherche pour le Développement 224, Universities of Montpellier 1 and 2), Montpellier, France
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44
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Ali JG, Agrawal AA. Asymmetry of plant-mediated interactions between specialist aphids and caterpillars on two milkweeds. Funct Ecol 2014. [DOI: 10.1111/1365-2435.12271] [Citation(s) in RCA: 83] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Jared G. Ali
- Department of Entomology; Michigan State University; East Lansing Michigan 48824 USA
| | - Anurag A. Agrawal
- Department of Ecology & Evolutionary Biology; Cornell University; Ithaca New York 14853 USA
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45
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Holzinger F, Wink M. Mediation of cardiac glycoside insensitivity in the monarch butterfly (Danaus plexippus): Role of an amino acid substitution in the ouabain binding site of Na(+),K (+)-ATPase. J Chem Ecol 2013; 22:1921-37. [PMID: 24227116 DOI: 10.1007/bf02028512] [Citation(s) in RCA: 68] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/1996] [Accepted: 05/16/1996] [Indexed: 12/01/2022]
Abstract
The Monarch butterfly (Danaus plexippus) sequesters cardiac glycosides (CG) for its chemical defense against predators. Larvae and adults of this butterfly are insensitive towards dietary cardiac glycosides, whereas other Lepidoptera are sensitive and intoxicated by ouabain. Ouabain inhibits Na(+),K(+)-ATPase by binding to its α-subunit. We have amplified and cloned the DNA-sequence encoding the respective ouabain binding site. Instead of the amino acid asparagine at position 122 in ouabain-sensitive insects, the Monarch has a histidine in the putative ouabain binding site, which consists of 12 amino acids. Starting with the CG-sensitive Na(+),K(+)-ATPase gene fromDrosophila, we converted pos. 122 to a histidine residue as inDanaus plexippus by site-directed mutagenesis. Human embryonic kidney cells (HEK) (which are sensitive to ouabain) were transfected with the mutated Na(+),K(+)-ATPase gene in a pSVDF-expression vector and showed a transient expression of the mutatedDrosophila Na(+),K(+)-ATPase. When treated with ouabain, the transfected cells tolerated ouabain at a concentration of 50 mM, whereas untransformed controls or controls transfected with the unmutatedDrosophila gene, showed a substantial mortality. This result implies that the asparagine to histidine exchange contributes to ouabain insensitivity in the Monarch. In two other CG-sequestering insects, e.g.,Danaus gilippus andSyntomeida epilais, the pattern of amino acid substitution differed, indicating that the Monarch has acquired this mutation independently during evolution.
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Affiliation(s)
- F Holzinger
- Institut für Pharmazeutische Biologie, Universität Heidelberg, Im Neuenheimer Feld 364, D-69120, Heidelberg, Germany
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46
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Petschenka G, Fandrich S, Sander N, Wagschal V, Boppré M, Dobler S. STEPWISE EVOLUTION OF RESISTANCE TO TOXIC CARDENOLIDES VIA GENETIC SUBSTITUTIONS IN THE NA+/K+-ATPASE OF MILKWEED BUTTERFLIES (LEPIDOPTERA: DANAINI). Evolution 2013; 67:2753-61. [DOI: 10.1111/evo.12152] [Citation(s) in RCA: 76] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2012] [Accepted: 04/15/2013] [Indexed: 11/28/2022]
Affiliation(s)
- Georg Petschenka
- Biozentrum Grindel; Martin-Luther-King-Platz 3; 20146; Hamburg; Germany
| | - Steffi Fandrich
- Biozentrum Grindel; Martin-Luther-King-Platz 3; 20146; Hamburg; Germany
| | - Nils Sander
- Biozentrum Grindel; Martin-Luther-King-Platz 3; 20146; Hamburg; Germany
| | - Vera Wagschal
- Biozentrum Grindel; Martin-Luther-King-Platz 3; 20146; Hamburg; Germany
| | - Michael Boppré
- Forstzoologisches Institut; Albert-Ludwigs-Universität; 79085; Freiburg; Germany
| | - Susanne Dobler
- Biozentrum Grindel; Martin-Luther-King-Platz 3; 20146; Hamburg; Germany
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47
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Sternberg ED, Lefèvre T, Li J, de Castillejo CLF, Li H, Hunter MD, de Roode JC. Food plant derived disease tolerance and resistance in a natural butterfly-plant-parasite interactions. Evolution 2012; 66:3367-76. [PMID: 23106703 DOI: 10.1111/j.1558-5646.2012.01693.x] [Citation(s) in RCA: 82] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Organisms can protect themselves against parasite-induced fitness costs through resistance or tolerance. Resistance includes mechanisms that prevent infection or limit parasite growth while tolerance alleviates the fitness costs from parasitism without limiting infection. Although tolerance and resistance affect host-parasite coevolution in fundamentally different ways, tolerance has often been ignored in animal-parasite systems. Where it has been studied, tolerance has been assumed to be a genetic mechanism, unaffected by the host environment. Here we studied the effects of host ecology on tolerance and resistance to infection by rearing monarch butterflies on 12 different species of milkweed food plants and infecting them with a naturally occurring protozoan parasite. Our results show that monarch butterflies experience different levels of tolerance to parasitism depending on the species of milkweed that they feed on, with some species providing over twofold greater tolerance than other milkweed species. Resistance was also affected by milkweed species, but there was no relationship between milkweed-conferred resistance and tolerance. Chemical analysis suggests that infected monarchs obtain highest fitness when reared on milkweeds with an intermediate concentration, diversity, and polarity of toxic secondary plant chemicals known as cardenolides. Our results demonstrate that environmental factors-such as interacting species in ecological food webs-are important drivers of disease tolerance.
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Affiliation(s)
- Eleanore D Sternberg
- Department of Biology, Emory University, 1510 Clifton Rd, Atlanta, Georgia 30322, USA.
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48
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Speed MP, Ruxton GD, Mappes J, Sherratt TN. Why are defensive toxins so variable? An evolutionary perspective. Biol Rev Camb Philos Soc 2012; 87:874-84. [PMID: 22540874 DOI: 10.1111/j.1469-185x.2012.00228.x] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Defensive toxins are widely used by animals, plants and micro-organisms to deter natural enemies. An important characteristic of such defences is diversity both in the quantity of toxins and the profile of specific defensive chemicals present. Here we evaluate evolutionary and ecological explanations for the persistence of toxin diversity within prey populations, drawing together a range of explanations from the literature, and adding new hypotheses. We consider toxin diversity in three ways: (1) the absence of toxicity in a proportion of individuals in an otherwise toxic prey population (automimicry); (2) broad variation in quantities of toxin within individuals in the same population; (3) variation in the chemical constituents of chemical defence. For each of these phenomena we identify alternative evolutionary explanations for the persistence of variation. One important general explanation is diversifying (frequency- or density-dependent) selection in which either costs of toxicity increase or their benefits decrease with increases in the absolute or relative abundance of toxicity in a prey population. A second major class of explanation is that variation in toxicity profiles is itself nonadaptive. One application of this explanation requires that predator behaviour is not affected by variation in levels or profiles of chemical defence within a prey population, and that there are no cost differences between different quantities or forms of toxins found within a population. Finally, the ecology and life history of the animal may enable some general predictions about toxin variation. For example, in animals which only gain their toxins in their immature forms (e.g. caterpillars on host plants) we may expect a decline in toxicity during adult life (or at least no change). By contrast, when toxins are also acquired during the adult form, we may for example expect the converse, in which young adults have less time to acquire toxicity than older adults. One major conclusion that we draw is that there are good reasons to consider within-species variation in defensive toxins as more than mere ecological noise. Rather there are a number of compelling evolutionary hypotheses which can explain and predict variation in prey toxicity.
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Affiliation(s)
- Michael P Speed
- Department of Evolution, Ecology and Behaviour, Institute of Integrative Biology, Faculty of Health & Life Sciences, University of Liverpool, UK.
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First-instar monarch larval growth and survival on milkweeds in southern California: effects of latex, leaf hairs and cardenolides. CHEMOECOLOGY 2011. [DOI: 10.1007/s00049-011-0099-x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/14/2022]
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Dobler S, Petschenka G, Pankoke H. Coping with toxic plant compounds--the insect's perspective on iridoid glycosides and cardenolides. PHYTOCHEMISTRY 2011; 72:1593-1604. [PMID: 21620425 DOI: 10.1016/j.phytochem.2011.04.015] [Citation(s) in RCA: 116] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/01/2010] [Revised: 03/30/2011] [Accepted: 04/20/2011] [Indexed: 05/27/2023]
Abstract
Specializing on host plants with toxic secondary compounds enforces specific adaptation in insect herbivores. In this review, we focus on two compound classes, iridoid glycosides and cardenolides, which can be found in the food plants of a large number of insect species that display various degrees of adaptation to them. These secondary compounds have very different modes of action: Iridoid glycosides are usually activated in the gut of the herbivores by β-glucosidases that may either stem from the food plant or be present in the gut as standard digestive enzymes. Upon cleaving, the unstable aglycone is released that unspecifically acts by crosslinking proteins and inhibiting enzymes. Cardenolides, on the other hand, are highly specific inhibitors of an essential ion carrier, the sodium pump. In insects exposed to both kinds of toxins, carriers either enabling the safe storage of the compounds away from the activating enzymes or excluding the toxins from sensitive tissues, play an important role that deserves further analysis. To avoid toxicity of iridoid glycosides, repression of activating enzymes emerges as a possible alternative strategy. Cardenolides, on the other hand, may lose their toxicity if their target site is modified and this strategy has evolved multiple times independently in cardenolide-adapted insects.
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Affiliation(s)
- Susanne Dobler
- Biocenter Grindel, Hamburg University, Martin-Luther-King Platz 3, 20146 Hamburg, Germany.
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