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Egan PA, Muola A, Parachnowitsch AL, Stenberg JA. Pollinators and herbivores interactively shape selection on strawberry defence and attraction. Evol Lett 2021; 5:636-643. [PMID: 34917402 PMCID: PMC8645195 DOI: 10.1002/evl3.262] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2020] [Revised: 09/10/2021] [Accepted: 09/26/2021] [Indexed: 12/14/2022] Open
Abstract
Tripartite interactions between plants, herbivores, and pollinators hold fitness consequences for most angiosperms. However, little is known on how plants evolve in response-and in particular what the net selective outcomes are for traits of shared relevance to pollinators and herbivores. In this study, we manipulated herbivory ("presence" and "absence" treatments) and pollination ("open" and "hand pollination" treatments) in a full factorial common-garden experiment with woodland strawberry (Fragaria vesca L.). This design allowed us to quantify the relative importance and interactive effects of herbivore- and pollinator-mediated selection on nine traits related to plant defence and attraction. Our results showed that pollinators imposed stronger selection than herbivores on traits related to both direct and indirect (i.e., tritrophic) defence. However, conflicting selection was imposed on inflorescence density: a trait that appears to be shared by herbivores and pollinators as a host plant signal. However, in all cases, selection imposed by one agent depended largely on the presence or ecological effect of the other, suggesting that dynamic patterns of selection could be a common outcome of these interactions in natural populations. As a whole, our findings highlight the significance of plant-herbivore-pollinator interactions as potential drivers of evolutionary change, and reveal that pollinators likely play an underappreciated role as selective agents on direct and in direct plant defence.
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Affiliation(s)
- Paul A. Egan
- Department of Plant Protection BiologySwedish University of Agricultural SciencesAlnarpSE‐23053Sweden
| | - Anne Muola
- Department of Plant Protection BiologySwedish University of Agricultural SciencesAlnarpSE‐23053Sweden
- Biodiversity UnitUniversity of TurkuTurku20014Finland
| | - Amy L. Parachnowitsch
- Department of BiologyUniversity of New BrunswickFrederictonNBE3B 5A3Canada
- Department of Plant Ecology and Evolution, Evolutionary Biology CentreUppsala UniversityUppsalaSE‐75236Sweden
| | - Johan A. Stenberg
- Department of Plant Protection BiologySwedish University of Agricultural SciencesAlnarpSE‐23053Sweden
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2
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Kasiotis KM, Evergetis E, Papachristos D, Vangelatou O, Antonatos S, Milonas P, Haroutounian SA, Machera K. An essay on ecosystem availability of Nicotiana glauca graham alkaloids: the honeybees case study. BMC Ecol 2020; 20:57. [PMID: 33158433 PMCID: PMC7646078 DOI: 10.1186/s12898-020-00325-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2020] [Accepted: 10/26/2020] [Indexed: 11/28/2022] Open
Abstract
BACKGROUND Invasive plant species pose a significant threat for fragile isolated ecosystems, occupying space, and consuming scarce local resources. Recently though, an additional adverse effect was recognized in the form of its secondary metabolites entering the food chain. The present study is elaborating on this subject with a specific focus on the Nicotiana glauca Graham (Solanaceae) alkaloids and their occurrence and food chain penetrability in Mediterranean ecosystems. For this purpose, a targeted liquid chromatography electrospray tandem mass spectrometric (LC-ESI-MS/MS) analytical method, encompassing six alkaloids and one coumarin derivative, utilizing hydrophilic interaction chromatography (HILIC) was developed and validated. RESULTS The method exhibited satisfactory recoveries, for all analytes, ranging from 75 to 93%, and acceptable repeatability and reproducibility. Four compounds (anabasine, anatabine, nornicotine, and scopoletin) were identified and quantified in 3 N. glauca flowers extracts, establishing them as potential sources of alien bio-molecules. The most abundant constituent was anabasine, determined at 3900 μg/g in the methanolic extract. These extracts were utilized as feeding treatments on Apis mellifera honeybees, resulting in mild toxicity documented by 16-18% mortality. A slightly increased effect was elicited by the methanolic extract containing anabasine at 20 μg/mL, where mortality approached 25%. Dead bees were screened for residues of the N. glauca flower extracts compounds and a significant mean concentration of anabasine was evidenced in both 10 and 20 μg/mL treatments, ranging from 51 to 92 ng/g per bee body weight. Scopoletin was also detected in trace amounts. CONCLUSIONS The mild toxicity of the extracts in conjunction with the alkaloid and coumarin residual detection in bees, suggest that these alien bio-molecules are transferred within the food chain, suggesting a chemical invasion phenomenon, never reported before.
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Affiliation(s)
- Konstantinos M Kasiotis
- Laboratory of Pesticides' Toxicology, Department of Pesticides Control and Phytopharmacy, Benaki Phytopathological Institute, 8 St. Delta str., 14561, Kifissia, Attica, Greece.
| | - Epameinondas Evergetis
- Laboratory of Nutritional Physiology and Feeding, Agricultural University of Athens, Iera Odos 75, 11855, Athens, Greece.
| | - Dimitrios Papachristos
- Laboratory of Agricultural Entomology, Department of Entomology and Agricultural Zoology, Benaki Phytopathological Institute, 8 St. Delta str., 14561, Kifissia, Attica, Greece
| | - Olympia Vangelatou
- Laboratory of Nutritional Physiology and Feeding, Agricultural University of Athens, Iera Odos 75, 11855, Athens, Greece
| | - Spyridon Antonatos
- Laboratory of Agricultural Entomology, Department of Entomology and Agricultural Zoology, Benaki Phytopathological Institute, 8 St. Delta str., 14561, Kifissia, Attica, Greece
| | - Panagiotis Milonas
- Biological Control Laboratory, Department of Entomology and Agricultural Zoology, Benaki Phytopathological Institute, 8 St. Delta str., 14561, Kifissia, Attica, Greece
| | - Serkos A Haroutounian
- Laboratory of Nutritional Physiology and Feeding, Agricultural University of Athens, Iera Odos 75, 11855, Athens, Greece
| | - Kyriaki Machera
- Laboratory of Pesticides' Toxicology, Department of Pesticides Control and Phytopharmacy, Benaki Phytopathological Institute, 8 St. Delta str., 14561, Kifissia, Attica, Greece
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Aguirre LA, Davis JK, Stevenson PC, Adler LS. Herbivory and Time Since Flowering Shape Floral Rewards and Pollinator-Pathogen Interactions. J Chem Ecol 2020; 46:978-986. [PMID: 32876829 DOI: 10.1007/s10886-020-01213-2] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2020] [Revised: 08/07/2020] [Accepted: 08/24/2020] [Indexed: 10/23/2022]
Abstract
Herbivory can induce chemical changes throughout plant tissues including flowers, which could affect pollinator-pathogen interactions. Pollen is highly defended compared to nectar, but no study has examined whether herbivory affects pollen chemistry. We assessed the effects of leaf herbivory on nectar and pollen alkaloids in Nicotiana tabacum, and how herbivory-induced changes in nectar and pollen affect pollinator-pathogen interactions. We damaged leaves of Nicotiana tabacum using the specialist herbivore Manduca sexta and compared nicotine and anabasine concentrations in nectar and pollen. We then pooled nectar and pollen by collection periods (within and after one month of flowering), fed them in separate experiments to bumble bees (Bombus impatiens) infected with the gut pathogen Crithidia bombi, and assessed infections after seven days. We did not detect alkaloids in nectar, and leaf damage did not alter the effect of nectar on Crithidia counts. In pollen, herbivory induced higher concentrations of anabasine but not nicotine, and alkaloid concentrations rose and then fell as a function of days since flowering. Bees fed pollen from damaged plants had Crithidia counts 15 times higher than bees fed pollen from undamaged plants, but only when pollen was collected after one month of flowering, indicating that both damage and time since flowering affected interaction outcomes. Within undamaged treatments, bees fed late-collected pollen had Crithidia counts 10 times lower than bees fed early-collected pollen, also indicating the importance of time since flowering. Our results emphasize the role of herbivores in shaping pollen chemistry, with consequences for interactions between pollinators and their pathogens.
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Affiliation(s)
- Luis A Aguirre
- Department of Biology, University of Massachusetts, Amherst, MA, 01003, USA.
- Graduate Program in Organismic and Evolutionary Biology, University of Massachusetts, Amherst, MA, 01003, USA.
| | - Julie K Davis
- Department of Entomology, Cornell University, Ithaca, NY, 14850, USA
| | - Philip C Stevenson
- Jodrell Laboratory, Royal Botanic Gardens, Kew, Surrey, TW9 3AB, UK
- Natural Resources Institute, University of Greenwich, Chatham, Kent, ME4 4TB, UK
| | - Lynn S Adler
- Department of Biology, University of Massachusetts, Amherst, MA, 01003, USA
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Evolution of the Angiosperms and Co-evolution of Secondary Metabolites, Especially of Alkaloids. ACTA ACUST UNITED AC 2020. [DOI: 10.1007/978-3-319-96397-6_22] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/18/2023]
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Parachnowitsch AL, Manson JS, Sletvold N. Evolutionary ecology of nectar. ANNALS OF BOTANY 2019; 123:247-261. [PMID: 30032269 PMCID: PMC6344224 DOI: 10.1093/aob/mcy132] [Citation(s) in RCA: 52] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/11/2018] [Accepted: 06/16/2018] [Indexed: 05/24/2023]
Abstract
Background Floral nectar is an important determinant of plant-pollinator interactions and an integral component of pollination syndromes, suggesting it is under pollinator-mediated selection. However, compared to floral display traits, we know little about the evolutionary ecology of nectar. Combining a literature review with a meta-analysis approach, we summarize the evidence for heritable variation in nectar traits and link this variation to pollinator response and plant fitness. We further review associations between nectar traits and floral signals and discuss them in the context of honest signalling and targets of selection. Scope Although nectar is strongly influenced by environmental factors, heritable variation in nectar production rate has been documented in several populations (mean h2 = 0.31). Almost nothing is known about heritability of other nectar traits, such as sugar and amino acid concentrations. Only a handful of studies have quantified selection on nectar traits, and few find statistically significant selection. Pollinator responses to nectar traits indicate they may drive selection, but studies tying pollinator preferences to plant fitness are lacking. So far, only one study conclusively identified pollinators as selective agents on a nectar trait, and the role of microbes, herbivores, nectar robbers and abiotic factors in nectar evolution is largely hypothetical. Finally, there is a trend for positive correlations among floral cues and nectar traits, indicating honest signalling of rewards. Conclusions Important progress can be made by studies that quantify current selection on nectar in natural populations, as well as experimental approaches that identify the target traits and selective agents involved. Signal-reward associations suggest that correlational selection may shape evolution of nectar traits, and studies exploring these more complex forms of natural selection are needed. Many questions about nectar evolution remain unanswered, making this a field ripe for future research.
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Affiliation(s)
- Amy L Parachnowitsch
- Plant Ecology and Evolution, Evolutionary Biology Centre, Uppsala University, Uppsala, Sweden
- Department of Biology, University of New Brunswick, Fredericton, New Brunswick, Canada
| | - Jessamyn S Manson
- Department of Biology, University of Virginia, Charlottesville, VA, USA
| | - Nina Sletvold
- Plant Ecology and Evolution, Evolutionary Biology Centre, Uppsala University, Uppsala, Sweden
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Soper Gorden NL, Adler LS. Consequences of multiple flower-insect interactions for subsequent plant-insect interactions and plant reproduction. AMERICAN JOURNAL OF BOTANY 2018; 105:1835-1846. [PMID: 30376158 DOI: 10.1002/ajb2.1182] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/20/2018] [Accepted: 08/16/2018] [Indexed: 06/08/2023]
Abstract
PREMISE OF THE STUDY Plants often interact simultaneously with multiple antagonists and mutualists that can alter plant traits at the phenotypic or genetic level, subsequent plant-insect interactions, and reproduction. Although many studies have examined the effects of single floral antagonisms on subsequent pollination and plant reproduction, we know very little about the combined, potentially non-additive effects of multiple flower-insect interactions. METHODS We simulated increased florivory, nectar robbing, and pollination on field-grown Impatiens capensis, which allowed us to determine interactive effects on five subsequent plant-insect interactions and 16 plant traits, including traits related to plant growth, floral attractiveness, floral defenses, and plant reproduction. KEY RESULTS All three manipulative treatments had significant non-additive effects on the behavior of subsequent floral visitors, indicating that the effect of floral visitors generally depended on the presence or behavior of others. Pollination increased visitation by both pollinators and nectar larcenists (robbers and thieves), while florivory reduced pollinator and larcenist visits. Surprisingly, supplemental pollination also increased leaf herbivory. Florivores often responded to manipulations in opposite ways than did nectar larcenists and pollinators, suggesting different mechanisms influencing visitors that consume nectar compared to floral tissue. While our treatments did not affect any floral trait measured, they non-additively impacted plant reproduction, with florivory having a larger overall impact than either nectar robbing or pollination. CONCLUSIONS These results emphasize the importance of understanding the context in which flower-insect interactions occur because the composition of the interacting community can have large and non-additive impacts on subsequent insect behavior and plant reproduction.
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Affiliation(s)
- Nicole L Soper Gorden
- Department of Biology, University of Massachusetts, 611 North Pleasant Street, Amherst, MA, 01003, USA
| | - Lynn S Adler
- Department of Biology, University of Massachusetts, 611 North Pleasant Street, Amherst, MA, 01003, USA
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Zhang J, Wang Z, Wen P, Qu Y, Tan K, Nieh JC. The reluctant visitor: an alkaloid in toxic nectar can reduce olfactory learning and memory in Asian honey bees. J Exp Biol 2018; 221:jeb.168344. [DOI: 10.1242/jeb.168344] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2017] [Accepted: 01/08/2018] [Indexed: 01/16/2023]
Abstract
The nectar of the thunder god vine, Tripterygium hypoglaucum, contains a terpenoid, triptolide (TRP), that may be toxic to the sympatric Asian honey bee, Apis cerana, because honey produced from this nectar is toxic to bees. However, these bees will forage on, recruit for, and pollinate this plant during a seasonal dearth of preferred food sources. Olfactory learning plays a key role in forager constancy and pollination, and we therefore tested the effects of acute and chronic TRP feeding on forager olfactory learning, using proboscis extension reflex conditioning. At concentrations of 0.5-10 µg TRP/ml, there were no learning effects of acute exposure. However, memory retention (1 h after the last learning trial) significantly decreased by 56% following acute consumption of 0.5 µg TRP/ml. Chronic exposure did not alter learning or memory, except at high concentrations (5 and 10 µg TRP/ml). TRP concentrations in nectar may therefore not significantly harm plant pollination. Surprisingly, TRP slightly increased bee survival, and thus other components in T. hypoglaucum honey may be toxic. Long term exposure to TRP could have colony effects, but these may be ameliorated by the bees’ aversion to T. hypoglaucum nectar when other food sources are available and, perhaps, by detoxification mechanisms. The co-evolution of this plant and its reluctant visitor may therefore likely illustrate a classic compromise between the interests of both actors.
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Affiliation(s)
- Junjun Zhang
- Chemical Ecology Group, Key Laboratory of Tropical Forest Ecology, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Kunming 650000, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Zhengwei Wang
- Chemical Ecology Group, Key Laboratory of Tropical Forest Ecology, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Kunming 650000, China
| | - Ping Wen
- Chemical Ecology Group, Key Laboratory of Tropical Forest Ecology, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Kunming 650000, China
| | - Yufeng Qu
- Chemical Ecology Group, Key Laboratory of Tropical Forest Ecology, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Kunming 650000, China
| | - Ken Tan
- Chemical Ecology Group, Key Laboratory of Tropical Forest Ecology, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Kunming 650000, China
| | - James C. Nieh
- Division of Biological Sciences Section of Ecology, Behavior, and Evolution University of California, San Diego La Jolla, California, USA
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Stevenson PC, Nicolson SW, Wright GA. Plant secondary metabolites in nectar: impacts on pollinators and ecological functions. Funct Ecol 2016. [DOI: 10.1111/1365-2435.12761] [Citation(s) in RCA: 165] [Impact Index Per Article: 20.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Philip C. Stevenson
- Royal Botanic Gardens, Kew SurreyTW9 3AB UK
- Natural Resources Institute University of Greenwich KentME4 4TB UK
| | - Susan W. Nicolson
- Department of Zoology & Entomology University of Pretoria Private Bag X20 Hatfield0028 South Africa
| | - Geraldine A. Wright
- Centre for Behaviour and Evolution Institute of Neuroscience Newcastle University Newcastle upon TyneNE1 7RU UK
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9
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Adler LS, Leege LM, Irwin RE. Geographic variation in resistance to nectar robbing and consequences for pollination. AMERICAN JOURNAL OF BOTANY 2016; 103:1819-1828. [PMID: 27765776 DOI: 10.3732/ajb.1600114] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/11/2016] [Accepted: 09/01/2016] [Indexed: 06/06/2023]
Abstract
PREMISE OF THE STUDY Floral evolution is frequently ascribed to selection by pollinators, but may also be shaped by antagonists. However, remarkably few studies have examined geographic mosaics in resistance to floral antagonists or the consequences for other floral interactions. METHODS Gelsemium sempervirens experiences frequent nectar robbing in northern Georgia, but rarely in southern Georgia. We conducted common-garden experiments in both locations using genotypes from each region and measured robbing, pollinator attraction, floral attractive and defensive traits, and plant reproduction. KEY RESULTS Nectar robbing was more than four times higher in the north vs. south, and pollinator visits did not differ between gardens. Across both gardens, northern genotypes were half as likely to be nectar-robbed but received half as many pollinator visits as southern genotypes, suggesting evolution of resistance to robbing at a cost of reduced pollinator attraction. Plant-level traits, such as height and number of flowers, were more closely associated with resistance to robbing than floral size, shape, or chemistry. Northern genotypes had lower female and estimated male reproduction compared to southern genotypes at both locations, which could be due to costs of resistance to nectar robbing, or costs of adaptations to other biotic or abiotic differences between regions. CONCLUSIONS Our study indicates that geographic variation can play a strong role structuring interactions with floral antagonists and mutualists and provides evidence consistent with the hypothesis that local resistance to nectar robbing imposes costs in terms of decreased pollinator attraction and reproduction.
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Affiliation(s)
- Lynn S Adler
- Department of Biology, 221 Morrill Science Center South, 611 N. Pleasant St., University of Massachusetts, Amherst, Massachusetts 01003 USA
| | - Lissa M Leege
- Department of Biology, Georgia Southern University, PO Box 8042-1, Statesboro, Georgia 30460 USA
| | - Rebecca E Irwin
- Department of Biological Sciences, Life Science Center, 78 College Street, Dartmouth College, Hanover, New Hampshire 03755 USA
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Kaczorowski RL, Markman S. Nectar alkaloids of tree tobacco can reduce Palestine sunbird foraging performance in a colour discrimination task. Anim Behav 2016. [DOI: 10.1016/j.anbehav.2016.05.015] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
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Caruso CM, Parachnowitsch AL. Do Plants Eavesdrop on Floral Scent Signals? TRENDS IN PLANT SCIENCE 2016; 21:9-15. [PMID: 26476624 DOI: 10.1016/j.tplants.2015.09.001] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/16/2015] [Revised: 09/02/2015] [Accepted: 09/07/2015] [Indexed: 05/18/2023]
Abstract
Plants emit a diverse array of volatile organic compounds that can function as cues to other plants. Plants can use volatiles emitted by neighbors to gain information about their environment, and respond by adjusting their phenotype. Less is known about whether the many different volatile signals that plants emit are all equally likely to function as cues to other plants. We review evidence for the function of floral volatile signals and conclude that plants are as likely to perceive and respond to floral volatiles as to other, better-studied volatiles. We propose that eavesdropping on floral volatile cues is particularly likely to be adaptive because plants can respond to these cues by adjusting traits that directly affect pollination and mating.
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Affiliation(s)
- Christina M Caruso
- Department of Integrative Biology, University of Guelph, Guelph, Ontario N1G 2W1, Canada.
| | - Amy L Parachnowitsch
- Plant Ecology and Evolution, Evolutionary Biology Centre, Uppsala University, 75236 Uppsala, Sweden
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Eliyahu D, McCall AC, Lauck M, Trakhtenbrot A. Florivory and nectar-robbing perforations in flowers of pointleaf manzanita Arctostaphylos pungens (Ericaceae) and their effects on plant reproductive success. ARTHROPOD-PLANT INTERACTIONS 2015; 9:613-622. [PMID: 26811740 PMCID: PMC4723111 DOI: 10.1007/s11829-015-9399-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/07/2015] [Accepted: 09/29/2015] [Indexed: 06/05/2023]
Abstract
Damage to petals may have varying effects on the reproductive success of the plant. The variation may depend on the kind of damage to the corolla. Whether the damage is limited to the corolla, as is usually the case with nectar-robbing perforations, or extending to the reproductive parts of the flower, as in the case of florivory holes, might determine the extent of the effect on the plant's reproduction. We examined the various perforations in the flowers of Arctostaphylos pungens and correlated their presence with fruiting success. We found that though florivory holes were highly associated with damage to reproductive parts, fruiting success did not differ significantly between flowers with the two kinds of damage. Although nectar-robbing perforations were not associated with reduced number of fruit produced, they were significantly correlated with reduced number of fruit that contained seemingly viable seeds. The implications of our findings are discussed in the context of pollination and antagonism.
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Affiliation(s)
- Dorit Eliyahu
- Department of Ecology and Evolutionary Biology, University of Arizona, Tucson, AZ, USA
| | | | - Marina Lauck
- Department of Biological Science, Florida State University, Tallahassee, FL, USA
| | - Ana Trakhtenbrot
- Division of Open Areas and Biodiversity, Israeli Ministry of Environmental Protection, Jerusalem, Israel
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Anthony WE, Palmer-Young EC, Leonard AS, Irwin RE, Adler LS. Testing Dose-Dependent Effects of the Nectar Alkaloid Anabasine on Trypanosome Parasite Loads in Adult Bumble Bees. PLoS One 2015; 10:e0142496. [PMID: 26545106 PMCID: PMC4636389 DOI: 10.1371/journal.pone.0142496] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2015] [Accepted: 10/22/2015] [Indexed: 12/02/2022] Open
Abstract
The impact of consuming biologically active compounds is often dose-dependent, where small quantities can be medicinal while larger doses are toxic. The consumption of plant secondary compounds can be toxic to herbivores in large doses, but can also improve survival in parasitized herbivores. In addition, recent studies have found that consuming nectar secondary compounds may decrease parasite loads in pollinators. However, the effect of compound dose on bee survival and parasite loads has not been assessed. To determine how secondary compound consumption affects survival and pathogen load in Bombus impatiens, we manipulated the presence of a common gut parasite, Crithidia bombi, and dietary concentration of anabasine, a nectar alkaloid produced by Nicotiana spp. using four concentrations naturally observed in floral nectar. We hypothesized that increased consumption of secondary compounds at concentrations found in nature would decrease survival of uninfected bees, but improve survival and ameliorate parasite loads in infected bees. We found medicinal effects of anabasine in infected bees; the high-anabasine diet decreased parasite loads and increased the probability of clearing the infection entirely. However, survival time was not affected by any level of anabasine concentration, or by interactive effects of anabasine concentration and infection. Crithidia infection reduced survival time by more than two days, but this effect was not significant. Our results support a medicinal role for anabasine at the highest concentration; moreover, we found no evidence for a survival-related cost of anabasine consumption across the concentration range found in nectar. Our results suggest that consuming anabasine at the higher levels of the natural range could reduce or clear pathogen loads without incurring costs for healthy bees.
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Affiliation(s)
- Winston E. Anthony
- Department of Biology, University of Massachusetts Amherst, Amherst, Massachusetts, United States of America
| | - Evan C. Palmer-Young
- Department of Biology, University of Massachusetts Amherst, Amherst, Massachusetts, United States of America
| | - Anne S. Leonard
- Department of Biology, University of Massachusetts Amherst, Amherst, Massachusetts, United States of America
| | - Rebecca E. Irwin
- Department of Biological Sciences, Dartmouth College, Hanover, New Hampshire, United States of America
- Department of Applied Ecology, North Carolina State University, Raleigh, North Carolina, United States of America
| | - Lynn S. Adler
- Department of Biology, University of Massachusetts Amherst, Amherst, Massachusetts, United States of America
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Grasso DA, Pandolfi C, Bazihizina N, Nocentini D, Nepi M, Mancuso S. Extrafloral-nectar-based partner manipulation in plant-ant relationships. AOB PLANTS 2015; 7:plv002. [PMID: 25589521 PMCID: PMC4326690 DOI: 10.1093/aobpla/plv002] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/08/2014] [Accepted: 12/17/2014] [Indexed: 05/27/2023]
Abstract
Plant-ant interactions are generally considered as mutualisms, with both parties gaining benefits from the association. It has recently emerged that some of these mutualistic associations have, however, evolved towards other forms of relationships and, in particular, that plants may manipulate their partner ants to make reciprocation more beneficial, thereby stabilizing the mutualism. Focusing on plants bearing extrafloral nectaries, we review recent studies and address three key questions: (i) how can plants attract potential partners and maintain their services; (ii) are there compounds in extrafloral nectar that could mediate partner manipulation; and (iii) are ants susceptible to such compounds? After reviewing the current knowledge on plant-ant associations, we propose a possible scenario where plant-derived chemicals, such as secondary metabolites, known to have an impact on animal brain, could have evolved in plants to attract and manipulate ant behaviour. This new viewpoint would place plant-animal interaction in a different ecological context, opening new ecological and neurobiological perspectives of drug seeking and use.
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Affiliation(s)
- D A Grasso
- Department of Life Sciences, University of Parma, Viale delle Scienze 11/a, 43124 Parma, Italy
| | - C Pandolfi
- LINV - Department of Agrifood Production and Environmental Sciences, University of Florence, Viale delle Idee 30, 50019 Sesto F.no, Florence, Italy
| | - N Bazihizina
- LINV - Department of Agrifood Production and Environmental Sciences, University of Florence, Viale delle Idee 30, 50019 Sesto F.no, Florence, Italy
| | - D Nocentini
- Department of Life Science, University of Siena, Via P.A. Mattioli 4, 53100 Siena, Italy
| | - M Nepi
- Department of Life Science, University of Siena, Via P.A. Mattioli 4, 53100 Siena, Italy
| | - S Mancuso
- LINV - Department of Agrifood Production and Environmental Sciences, University of Florence, Viale delle Idee 30, 50019 Sesto F.no, Florence, Italy
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