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Brett MF, Strauss P, van Wyk K, Vaughan IP, Memmott J. Spillover effects from invasive Acacia alter the plant-pollinator networks and seed production of native plants. Proc Biol Sci 2024; 291:20232941. [PMID: 38593850 PMCID: PMC11003774 DOI: 10.1098/rspb.2023.2941] [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: 12/28/2023] [Accepted: 03/07/2024] [Indexed: 04/11/2024] Open
Abstract
Invasive flowering plants can disrupt plant-pollinator networks. This is well documented where invasives occur amongst native plants; however, the potential for 'spillover' effects of invasives that form stands in adjacent habitats are less well understood. Here we quantify the impact of two invasive Australian species, Acacia saligna and Acacia longifolia, on the plant-pollinator networks in fynbos habitats in South Africa. We compared networks from replicate 1 ha plots of native vegetation (n = 21) that were subjected to three treatments: (1) at least 400 m from flowering Acacia; (2) adjacent to flowering Acacia, or (3) adjacent to flowering Acacia where all Acacia flowers were manually removed. We found that native flowers adjacent to stands of flowering Acacia received significantly more insect visits, especially from beetles and Apis mellifera capensis, and that visitation was more generalized. We also recorded visitation to, and the seed set of, three native flowering species and found that two received more insect visits, but produced fewer seeds, when adjacent to flowering Acacia. Our research shows that 'spillover' effects of invasive Acacia can lead to significant changes in visitation and seed production of native co-flowering species in neighbouring habitats-a factor to be considered when managing invaded landscapes.
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Affiliation(s)
- Maisie F. Brett
- School of Biological Sciences, University of Bristol, Bristol BS8 1TQ, UK
| | - Paula Strauss
- Grootbos Foundation, Gansbaai 7220, Western Cape, South Africa
| | - Kurt van Wyk
- Grootbos Foundation, Gansbaai 7220, Western Cape, South Africa
| | - Ian P. Vaughan
- Cardiff School of Biosciences, Cardiff University, Cardiff CF10 3AX, UK
| | - Jane Memmott
- School of Biological Sciences, University of Bristol, Bristol BS8 1TQ, UK
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2
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Porto GF, Pezzonia JH, Del-Claro K. Extrafloral Nectary-Bearing Plants Recover Ant Association Benefits Faster and More Effectively after Frost-Fire Events Than Frost. PLANTS (BASEL, SWITZERLAND) 2023; 12:3592. [PMID: 37896055 PMCID: PMC10610396 DOI: 10.3390/plants12203592] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/08/2023] [Revised: 10/10/2023] [Accepted: 10/14/2023] [Indexed: 10/29/2023]
Abstract
The Cerrado confronts threats such as fire and frost due to natural or human-induced factors. These disturbances trigger attribute changes that impact biodiversity. Given escalating climate extremes, understanding the effects of these phenomena on ecological relationships is crucial for biodiversity conservation. To understand how fire and frost affect interactions and influence biological communities in the Cerrado, our study aimed to comprehend the effects of these two disturbances on extrafloral nectar (EFN)-bearing plants (Ouratea spectabilis, Ochnaceae) and their interactions. Our main hypothesis was that plants affected by fire would grow again more quickly than those affected only by frost due to the better adaptation of Cerrado flora to fire. The results showed that fire accelerated the regrowth of O. spectabilis. Regrowth in plants with EFNs attracted ants that proved to be efficient in removing herbivores, significantly reducing foliar herbivory rates in this species, when compared to the species without EFNs, or when ant access was prevented through experimental manipulation. Post-disturbance ant and herbivore populations were low, with frost leading to greater reductions. Ant richness and diversity are higher where frost precedes fire, suggesting that fire restores Cerrado ecological interactions better than frost, with less impact on plants, ants, and herbivores.
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Affiliation(s)
- Gabriela Fraga Porto
- Programa de Pós-Graduação em Biologia Vegetal, Instituto de Biologia, Universidade de Uberlândia, Uberlândia 38400-902, MG, Brazil;
- Programa de Pós-Graduação em Entomologia, Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto—FFCLRP, Universidade de São Paulo, Ribeirão Preto 14040-901, SP, Brazil;
- Laboratório de Ecologia Comportamental e de Interações, Instituto de Biologia, Universidade Federal de Uberlândia, Uberlândia 38400-902, MG, Brazil
| | - José Henrique Pezzonia
- Programa de Pós-Graduação em Entomologia, Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto—FFCLRP, Universidade de São Paulo, Ribeirão Preto 14040-901, SP, Brazil;
- Laboratório de Ecologia Comportamental e de Interações, Instituto de Biologia, Universidade Federal de Uberlândia, Uberlândia 38400-902, MG, Brazil
| | - Kleber Del-Claro
- Laboratório de Ecologia Comportamental e de Interações, Instituto de Biologia, Universidade Federal de Uberlândia, Uberlândia 38400-902, MG, Brazil
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3
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Nathan P, Economo EP, Guénard B, Simonsen AK, Frederickson ME. Generalized mutualisms promote range expansion in both plant and ant partners. Proc Biol Sci 2023; 290:20231083. [PMID: 37700642 PMCID: PMC10498038 DOI: 10.1098/rspb.2023.1083] [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: 05/15/2023] [Accepted: 08/14/2023] [Indexed: 09/14/2023] Open
Abstract
Mutualism improves organismal fitness, but strong dependence on another species can also limit a species' ability to thrive in a new range if its partner is absent. We assembled a large, global dataset on mutualistic traits and species ranges to investigate how multiple plant-animal and plant-microbe mutualisms affect the spread of legumes and ants to novel ranges. We found that generalized mutualisms increase the likelihood that a species establishes and thrives beyond its native range, whereas specialized mutualisms either do not affect or reduce non-native spread. This pattern held in both legumes and ants, indicating that specificity between mutualistic partners is a key determinant of ecological success in a new habitat. Our global analysis shows that mutualism plays an important, if often overlooked, role in plant and insect invasions.
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Affiliation(s)
- Pooja Nathan
- Department of Ecology & Evolutionary Biology, University of Toronto, 25 Willcocks Street, Toronto M5S 3B2, Ontario, Canada
| | - Evan P. Economo
- Biodiversity and Biocomplexity Unit, Okinawa Institute of Science and Technology Graduate University, Onna, Okinawa 904-0495, Japan
| | - Benoit Guénard
- School of Biological Sciences, The University of Hong Kong, Pok Fu Lam, Hong Kong
| | - Anna K. Simonsen
- Department of Biological Sciences, Florida International University, 11200 SW 8th St, Miami, FL 33199, USA
| | - Megan E. Frederickson
- Department of Ecology & Evolutionary Biology, University of Toronto, 25 Willcocks Street, Toronto M5S 3B2, Ontario, Canada
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4
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Lamont BB, Grey J. Extrafloral nectar as entrée and elaiosomes as main course for ant visitors to a fireprone, mediterranean-climate shrub. Ecol Evol 2022; 12:e9500. [PMID: 36381400 PMCID: PMC9643124 DOI: 10.1002/ece3.9500] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2022] [Revised: 10/20/2022] [Accepted: 10/21/2022] [Indexed: 11/11/2022] Open
Abstract
Thousands of plants produce both extrafloral nectaries (EFNs) on their leaves and nutrient-rich appendages on their diaspores (elaiosomes). Although their individual ecology is well-known, any possible functional link between these structures has almost always been ignored. Here, we recognized their co-presence in the shrub, Adenanthos cygnorum (Proteaceae), and studied their function and interaction. We observed that the same ants frequently visit both structures, seeds are attractive to vertebrate granivores but are released into a leafy cup from where they are harvested by ants and taken to their nests, from which seeds, lacking elaiosomes, germinate after fire. We showed that juvenile plants do not produce EFNs and are not visited by ants. We conclude that EFNs are not just an indirect adaptation to minimize herbivory via aggressive ant visitors (the role of a minority) but specifically enhance reproductive success in two ways: First, by inducing ants to visit the plant as a reliable food source throughout the year. Second, by promoting discovery of the seasonally available, elaiosome-bearing seeds for transport to their nests (the majority of visitors), so avoiding the risk of granivory should seeds instead fall to the ground. Parasitoid wasps play a supporting role in controlling the main insect herbivore whose larvae devour the reproductive apices. Thus, the EFN-elaiosome relationship has three components that enhance species fitness: foliage protection, seed transport, and granivore escape. A similar system has been described only once before (in an unrelated biome) and, consistent with the objectives of ecology as an integrative science, deserves wider study.
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Affiliation(s)
- Byron B. Lamont
- Ecology Section, School of Life and Molecular SciencesCurtin UniversityPerthWestern AustraliaAustralia
| | - James Grey
- Ecology Section, School of Life and Molecular SciencesCurtin UniversityPerthWestern AustraliaAustralia
- Present address:
Assurance SystemsNorth SydneyNew South WalesAustralia
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5
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Milligan PD, Martin TA, John GP, Riginos C, Goheen JR, Carpenter SM, Palmer TM. Mutualism disruption by an invasive ant reduces carbon fixation for a foundational East African ant-plant. Ecol Lett 2021; 24:1052-1062. [PMID: 33745197 DOI: 10.1111/ele.13725] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2021] [Revised: 02/16/2021] [Accepted: 02/16/2021] [Indexed: 11/30/2022]
Abstract
Invasive ants shape assemblages and interactions of native species, but their effect on fundamental ecological processes is poorly understood. In East Africa, Pheidole megacephala ants have invaded monodominant stands of the ant-tree Acacia drepanolobium, extirpating native ant defenders and rendering trees vulnerable to canopy damage by vertebrate herbivores. We used experiments and observations to quantify direct and interactive effects of invasive ants and large herbivores on A. drepanolobium photosynthesis over a 2-year period. Trees that had been invaded for ≥ 5 years exhibited 69% lower whole-tree photosynthesis during key growing seasons, resulting from interaction between invasive ants and vertebrate herbivores that caused leaf- and canopy-level photosynthesis declines. We also surveyed trees shortly before and after invasion, finding that recent invasion induced only minor changes in leaf physiology. Our results from individual trees likely scale up, highlighting the potential of invasive species to alter ecosystem-level carbon fixation and other biogeochemical cycles.
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Affiliation(s)
- Patrick D Milligan
- Department of Biology, University of Florida, Gainesville, FL, USA.,Mpala Research Centre, Nanyuki, Kenya
| | - Timothy A Martin
- School of Forest Resources and Conservation, University of Florida, Gainesville, FL, USA
| | - Grace P John
- Department of Biology, University of Florida, Gainesville, FL, USA
| | | | - Jacob R Goheen
- Mpala Research Centre, Nanyuki, Kenya.,Department of Zoology and Physiology, University of Wyoming, Laramie, WY, USA
| | | | - Todd M Palmer
- Department of Biology, University of Florida, Gainesville, FL, USA.,Mpala Research Centre, Nanyuki, Kenya
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6
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Calixto ES, Lange D, Del‐Claro K. Net benefits of a mutualism: Influence of the quality of extrafloral nectar on the colony fitness of a mutualistic ant. Biotropica 2021. [DOI: 10.1111/btp.12925] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Eduardo Soares Calixto
- Programa de Pós‐Graduação em Entomologia Faculdade de Filosofia, Ciências e Letras Universidade de São Paulo Ribeirão Preto SP Brazil
| | - Denise Lange
- Universidade Tecnológica Federal do Paraná Santa Helena PR Brazil
| | - Kleber Del‐Claro
- Laboratório de Ecologia Comportamental e de Interações Instituto de Biologia Universidade Federal de Uberlândia Uberlândia MG Brazil
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7
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Density dependence and the spread of invasive big-headed ants (Pheidole megacephala) in an East African savanna. Oecologia 2021; 195:667-676. [PMID: 33506295 DOI: 10.1007/s00442-021-04859-1] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2020] [Accepted: 01/14/2021] [Indexed: 10/22/2022]
Abstract
Supercolonial ants are among the largest cooperative units in nature, attaining extremely high densities. How these densities feed back into their population growth rates and how abundance and extrinsic factors interact to affect their population dynamics remain open questions. We studied how local worker abundance and extrinsic factors (rain, tree density) affect population growth rate and spread in the invasive big-headed ant, which is disrupting a keystone mutualism between acacia trees and native ants in parts of East Africa. We measured temporal changes in big-headed ant (BHA) abundance and rates of spread over 20 months along eight transects, extending from areas behind the front with high BHA abundances to areas at the invasion front with low BHA abundances. We used models that account for negative density dependence and incorporated extrinsic factors to determine what variables best explain variation in local population growth rates. Population growth rates declined with abundance, however, the strength of density dependence decreased with abundance. We suggest that weaker density dependence at higher ant abundances may be due to the beneficial effect of cooperative behavior that partially counteracts resource limitation. Rainfall and tree density had minor effects on ant population dynamics. BHA spread near 50 m/year, more than previous studies reported and comparable to rates of spread of other supercolonial ants. Although we did not detect declines in abundance in areas invaded a long time ago (> 10 years), continued monitoring of abundance at invaded sites may help to better understand the widespread collapse of many invasive ants.
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8
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Palmer TM, Riginos C, Milligan PD, Hays BR, Pietrek AG, Maiyo NJ, Mutisya S, Gituku B, Musila S, Carpenter S, Goheen JR. Frenemy at the gate: Invasion by Pheidole megacephala facilitates a competitively subordinate plant ant in Kenya. Ecology 2020; 102:e03230. [PMID: 33098658 DOI: 10.1002/ecy.3230] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/01/2020] [Revised: 07/17/2020] [Accepted: 09/14/2020] [Indexed: 11/11/2022]
Abstract
Biological invasions can lead to the reassembly of communities and understanding and predicting the impacts of exotic species on community structure and functioning are a key challenge in ecology. We investigated the impact of a predatory species of invasive ant, Pheidole megacephala, on the structure and function of a foundational mutualism between Acacia drepanolobium and its associated acacia-ant community in an East African savanna. Invasion by P. megacephala was associated with the extirpation of three extrafloral nectar-dependent Crematogaster acacia ant species and strong increases in the abundance of a competitively subordinate and locally rare acacia ant species, Tetraponera penzigi, which does not depend on host plant nectar. Using a combination of long-term monitoring of invasion dynamics, observations and experiments, we demonstrate that P. megacephala directly and indirectly facilitates T. penzigi by reducing the abundance of T. penzigi's competitors (Crematogaster spp.), imposing recruitment limitation on these competitors, and generating a landscape of low-reward host plants that favor colonization and establishment by the strongly dispersing T. penzigi. Seasonal variation in use of host plants by P. megacephala may further increase the persistence of T. penzigi colonies in invaded habitat. The persistence of the T. penzigi-A. drepanolobium symbiosis in invaded areas afforded host plants some protection against herbivory by elephants (Loxodonta africana), a key browser that reduces tree cover. However, elephant damage on T. penzigi-occupied trees was higher in invaded than in uninvaded areas, likely owing to reduced T. penzigi colony size in invaded habitats. Our results reveal the mechanisms underlying the disruption of this mutualism and suggest that P. megacephala invasion may drive long-term declines in tree cover, despite the partial persistence of the ant-acacia symbiosis in invaded areas.
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Affiliation(s)
- Todd M Palmer
- Department of Biology, University of Florida, Gainesville, Florida, 32601, USA.,Mpala Research Centre, Box 555, Nanyuki, Kenya
| | - Corinna Riginos
- The Nature Conservancy, Lander, Wyoming, 82520, USA.,Department of Zoology and Physiology, University of Wyoming, Laramie, Wyoming, 82071, USA
| | - Patrick D Milligan
- Department of Biology, University of Florida, Gainesville, Florida, 32601, USA.,Mpala Research Centre, Box 555, Nanyuki, Kenya
| | - Brandon R Hays
- Mpala Research Centre, Box 555, Nanyuki, Kenya.,Department of Zoology and Physiology, University of Wyoming, Laramie, Wyoming, 82071, USA
| | - Alejandro G Pietrek
- Department of Biology, University of Florida, Gainesville, Florida, 32601, USA.,Mpala Research Centre, Box 555, Nanyuki, Kenya.,Instituto de Bio y Geociencias del NOA (IBIGEO), Salta, Argentina
| | - Nelly J Maiyo
- Conservation Department, Ol Pejeta Conservancy, Private Bag-10400, Nanyuki, Kenya
| | - Samuel Mutisya
- Conservation Department, Ol Pejeta Conservancy, Private Bag-10400, Nanyuki, Kenya
| | - Benard Gituku
- Conservation Department, Ol Pejeta Conservancy, Private Bag-10400, Nanyuki, Kenya
| | - Simon Musila
- Mammalogy Section, National Museums of Kenya, Nairobi, Kenya
| | - Scott Carpenter
- School of Forestry and Environmental Studies, Yale University, New Haven, Connecticut, 06520, USA
| | - Jacob R Goheen
- Mpala Research Centre, Box 555, Nanyuki, Kenya.,Department of Zoology and Physiology, University of Wyoming, Laramie, Wyoming, 82071, USA
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9
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Contrasting effects of herbivore damage type on extrafloral nectar production and ant attendance. ACTA OECOLOGICA-INTERNATIONAL JOURNAL OF ECOLOGY 2020. [DOI: 10.1016/j.actao.2020.103638] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
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10
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Mesquita-Neto JN, Paiva EAS, Galetto L, Schlindwein C. Nectar Secretion of Floral Buds of Tococa guianensis Mediates Interactions With Generalist Ants That Reduce Florivory. FRONTIERS IN PLANT SCIENCE 2020; 11:627. [PMID: 32508868 PMCID: PMC7253585 DOI: 10.3389/fpls.2020.00627] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/18/2019] [Accepted: 04/23/2020] [Indexed: 06/11/2023]
Abstract
The specialised mutualism between Tococa guianensis and ants housed in its leaf domatia is a well-known example of myrmecophily. A pollination study on this species revealed that flowers in the bud stage exude a sugary solution that is collected by ants. Given the presence of this unexpected nectar secretion, we investigated how, where, and when floral buds of T. guianensis secret nectar and what function it serves. We studied a population of T. guianensis occurring in a swampy area in the Cerrado of Brazil by analyzing the chemical composition and secretion dynamics of the floral-bud nectar and the distribution and ultrastructure of secretory tissues. We also measured flower damage using ant-exclusion experiments. Floral bud nectar was secreted at the tip of the petals, which lack a typical glandular structure but possess distinctive mesophyll due to the presence of numerous calcium oxalate crystals. The nectar, the production of which ceased after flower opening, was composed mainly of sucrose and low amounts of glucose and fructose. Nectar was consumed by generalist ants and sporadically by stingless bees. Ant exclusion experiments resulted in significantly increased flower damage. The floral nectar of T. guianensis is produced during the bud stage. This bud-nectar has the extranuptial function of attracting generalist ants that reduce florivory. Pollen is the unique floral resource attracting pollinators during anthesis. Tococa guianensis, thus, establishes relationships with two functional groups of ant species: specialist ants acting against herbivory and generalist ants acting against florivory.
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Affiliation(s)
- José Neiva Mesquita-Neto
- Departamento de Botânica, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil
- Centro de Investigación en Estudios Avanzados del Maule, Vicerrectoría de Investigación y Postgrado, Universidad Católica del Maule, Talca, Chile
| | - Elder Antônio Sousa Paiva
- Departamento de Botânica, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil
| | - Leonardo Galetto
- Instituto Multidisciplinario de Biología Vegetal (UNC-CONICET), Universidad Nacional de Córdoba, Córdoba, Argentina
| | - Clemens Schlindwein
- Departamento de Botânica, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil
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11
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Johnson LR, Breger B, Drummond F. Novel plant–insect interactions in an urban environment: enemies, protectors, and pollinators of invasive knotweeds. Ecosphere 2019. [DOI: 10.1002/ecs2.2885] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Affiliation(s)
- Lea R. Johnson
- Longwood Gardens, Research and Conservation Division Kennett Square Pennsylvania 19348 USA
- Department of Biology Bates College Lewiston Maine 04240 USA
- Department of Plant Science and Landscape Architecture University of Maryland College Park Maryland 20742 USA
| | - Benjamin Breger
- Department of Biology Bates College Lewiston Maine 04240 USA
| | - Francis Drummond
- School of Biology and Ecology University of Maine Orono Maine 04469 USA
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12
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13
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Yamawo A, Suzuki N. Induction and relaxation of extrafloral nectaries in response to simulated herbivory in young Mallotus japonicus plants. JOURNAL OF PLANT RESEARCH 2018; 131:255-260. [PMID: 29090369 DOI: 10.1007/s10265-017-0988-3] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/12/2017] [Accepted: 10/09/2017] [Indexed: 05/09/2023]
Abstract
The disadvantage of induced defenses compared with constitutive defenses is the time during which a plant is vulnerable to herbivory before activation. There is obvious importance in determining the costs and benefits of induced defenses. Some plants produce extrafloral nectaries (EFNs), which attract ants that protect against herbivores, and induce EFNs and extrafloral nectar in response to leaf damage. To understand induction of indirect defense by ants, we investigated the induction and relaxation of extrafloral nectar secretion and EFN formation after artificial leaf damage in young Mallotus japonicus. Plants were grown under control or leaf damage conditions a greenhouse or in the field. Following artificial leaf damage, we assessed secretion of extrafloral nectar and the number of ant workers on plants. We measured the number of EFNs on each of seven leaves produced after leaf damage. Extrafloral nectar secretion was induced within 1 day following leaf damage, resulting in the attraction of numerous ant workers, and the extrafloral nectar secretion decreased to initial levels after 7 days. The number of EFNs was largest on the first leaf and smallest on the sixth leaf produced after leaf damage, but the total number of EFNs did not differ between treatments. Thus, M. japonicus rapidly induces extrafloral nectar secretion after leaf damage, followed by relaxation. Furthermore, following induction of EFNs on newly produced leaves, it may decrease the cost of induction by reducing the number of EFNs on leaves produced later.
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Affiliation(s)
- Akira Yamawo
- Department of Biology, Faculty of Agriculture and Life Science, Hirosaki University, 1 Bunkyo-cho, Hirosaki, 036-8560, Japan.
| | - Nobuhiko Suzuki
- Department of Applied Biological Sciences, Faculty of Agriculture, Saga University, Saga, 840-8502, Japan
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14
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Osbrink WLA, Goolsby JA, Thomas DB, Mejorado A, Showler AT, Pérez De León A. Higher Ant Diversity in Native Vegetation Than in Stands of the Invasive Arundo, Arundo donax L., Along the Rio Grande Basin in Texas, USA. INTERNATIONAL JOURNAL OF INSECT SCIENCE 2017; 9:1179543317724756. [PMID: 28835737 PMCID: PMC5555496 DOI: 10.1177/1179543317724756] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/03/2017] [Accepted: 07/01/2017] [Indexed: 06/07/2023]
Abstract
Our hypothesis was that there will be greater ant biodiversity in heterogeneous native vegetation compared with Arundo stands. Changes in ant biodiversity due to Arundo invasion may be one of the ecological changes in the landscape that facilitates the invasion of cattle fever ticks from Mexico where they are endemic. Ants collected in pitfall traps were identified and compared between native vegetation and stands of Arundo, Arundo donax L., monthly for a year at 10 locations. A total of 82 752 ants representing 28 genera and 76 species were collected. More ants were collected in the native vegetation which also had greater species richness and biological diversity than ants collected from Arundo stands. It is suggested that the greater heterogeneous nature of native vegetation provided greater and more predictable nourishment in the form of nectars and more abundant arthropod prey when compared with Arundo stands.
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Affiliation(s)
- Weste LA Osbrink
- Knipling-Bushland U.S. Livestock Insects Research Laboratory, USDA-ARS-SPA, Kerrville, TX, USA
| | - John A Goolsby
- Cattle Fever Tick Research Lab, USDA-ARS, Edinburg, TX, USA
| | - Don B Thomas
- Cattle Fever Tick Research Lab, USDA-ARS, Edinburg, TX, USA
| | - Alba Mejorado
- Cattle Fever Tick Research Lab, USDA-ARS, Edinburg, TX, USA
| | - Allan T Showler
- Knipling-Bushland U.S. Livestock Insects Research Laboratory, USDA-ARS-SPA, Kerrville, TX, USA
| | - Adalberto Pérez De León
- Knipling-Bushland U.S. Livestock Insects Research Laboratory, USDA-ARS-SPA, Kerrville, TX, USA
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15
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16
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Belchior C, Sendoya SF, Del-Claro K. Temporal Variation in the Abundance and Richness of Foliage-Dwelling Ants Mediated by Extrafloral Nectar. PLoS One 2016; 11:e0158283. [PMID: 27438722 PMCID: PMC4954677 DOI: 10.1371/journal.pone.0158283] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2015] [Accepted: 06/13/2016] [Indexed: 12/04/2022] Open
Abstract
Plants bearing extrafloral nectaries (EFNs) are common in the Brazilian cerrado savanna, where climatic conditions having marked seasonality influence arboreal ant fauna organization. These ant-plant interactions have rarely been studied at community level. Here, we tested whether: 1) EFN-bearing plants are more visited by ants than EFN-lacking plants; 2) ant visitation is higher in the rainy season than in dry season; 3) plants producing young leaves are more visited than those lacking young leaves in the rainy season; 4) during the dry season, plants with old leaves and flowers are more visited than plants with young leaves and bare of leaves or flowers; 5) the composition of visiting ant fauna differs between plants with and without EFNs. Field work was done in a cerrado reserve near Uberlândia, MG State, Brazil, along ten transects (total area 3,000 m2), in the rainy (October-January) and dry seasons (April-July) of 2010–2011. Plants (72 species; 762 individuals) were checked three times per season for ant presence. Results showed that 21 species (29%) and 266 individuals (35%) possessed EFNs. These plants attracted 38 ant species (36 in rainy, 26 in dry season). In the rainy season, plants with EFNs had higher ant abundance/richness than plants without EFNs, but in the dry season, EFN presence did not influence ant visitation. Plant phenology affected ant richness and abundance in different ways: plants with young leaves possessed higher ant richness in the rainy season, but in the dry season ant abundance was higher on plants possessing old leaves or flowers. The species composition of plant-associated ant communities, however, did not differ between plants with and without EFNs in either season. These findings suggest that the effect of EFN presence on a community of plant-visiting ants is context dependent, being conditioned to seasonal variation.
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Affiliation(s)
- Ceres Belchior
- Programa de Pós-Graduação em Ecologia e Conservação de Recursos Naturais, Instituto de Biologia, Universidade Federal de Uberlândia, Uberlândia MG, Brazil
| | - Sebastián F. Sendoya
- Departamento de Biologia Animal, Instituto de Biologia, Universidade Estadual de Campinas, C.P. 6109, Campinas SP, Brazil
| | - Kleber Del-Claro
- Programa de Pós-Graduação em Ecologia e Conservação de Recursos Naturais, Instituto de Biologia, Universidade Federal de Uberlândia, Uberlândia MG, Brazil
- * E-mail:
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Jones IM, Koptur S. Quantity over quality: light intensity, but not red/far-red ratio, affects extrafloral nectar production in Senna mexicana var. chapmanii. Ecol Evol 2015; 5:4108-14. [PMID: 26445662 PMCID: PMC4588640 DOI: 10.1002/ece3.1644] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2015] [Revised: 06/28/2015] [Accepted: 07/08/2015] [Indexed: 02/02/2023] Open
Abstract
Extrafloral nectar (EFN) mediates food‐for‐protection mutualisms between plants and insects and provides plants with a form of indirect defense against herbivory. Understanding sources of variation in EFN production is important because such variations affect the number and identity of insect visitors and the effectiveness of plant defense. Light represents a potentially crucial tool for regulating resource allocation to defense, as it not only contributes energy but may help plants to anticipate future conditions. Low red/far‐red (R/FR) light ratios can act as a signal of the proximity of competing plants. Exposure to such light ratios has been shown to promote competitive behaviors that coincide with reduced resource allocation to direct chemical defenses. Little is known, however, about how such informational light signals might affect indirect defenses such as EFN, and the interactions that they mediate. Through controlled glasshouse experiments, we investigated the effects of light intensity, and R/FR light ratios, on EFN production in Senna mexicana var. chapmanii. Plants in light‐limited conditions produced significantly less EFN, and leaf damage elicited increased EFN production regardless of light conditions. Ratios of R/FR light, however, did not appear to affect EFN production in either damaged or undamaged plants. Understanding the effects of light on indirect defenses is of particular importance for plants in the threatened pine rockland habitats of south Florida, where light conditions are changing in predictable ways following extensive fragmentation and subsequent mismanagement. Around 27% of species in these habitats produce EFN and may rely on insect communities for defense.
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Affiliation(s)
- Ian M Jones
- Department of Biological Sciences Florida International University Miami Florida
| | - Suzanne Koptur
- Department of Biological Sciences Florida International University Miami Florida
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Riginos C, Karande MA, Rubenstein DI, Palmer TM. Disruption of a protective ant-plant mutualism by an invasive ant increases elephant damage to savanna trees. Ecology 2015; 96:654-61. [PMID: 26236862 DOI: 10.1890/14-1348.1] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Invasive species can indirectly affect ecosystem processes via the disruption of mutualisms. The mutualism between the whistling thorn acacia (Acacia drepanolobium) and four species of symbiotic ants is an ecologically important one; ants strongly defend trees against elephants, which can otherwise have dramatic impacts on tree cover. In Laikipia, Kenya, the invasive big-headed ant (Pheidole megacephala) has established itself at numerous locations within the last 10-15 years. In invaded areas on five properties, we found that three species of symbiotic Crematogaster ants were virtually extirpated, whereas Tetraponera penzigi co-occurred with P. megacephala. T. penzigi appears to persist because of its nonaggressive behavior; in a whole-tree translocation experiment, Crematogaster defended host trees against P. megacephala, but were extirpated from trees within hours. In contrast, T. penzigi retreated into domatia and withstood invading ants for >30 days. In the field, the loss of defensive Crematogaster ants in invaded areas led to a five- to sevenfold increase in the number of trees catastrophically damaged by elephants compared to uninvaded areas. In savannas, tree cover drives many ecosystem processes and provides essential forage for many large mammal species; thus, the invasion of big-headed ants may strongly alter the dynamics and diversity of East Africa's whistling thorn savannas by disrupting this system's keystone acaciaant mutualism.
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Martínez-Bauer AE, Martínez GC, Murphy DJ, Burd M. Multitasking in a plant–ant interaction: how does Acacia myrtifolia manage both ants and pollinators? Oecologia 2015; 178:461-71. [DOI: 10.1007/s00442-014-3215-0] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2014] [Accepted: 12/23/2014] [Indexed: 10/24/2022]
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Heil M. Extrafloral nectar at the plant-insect interface: a spotlight on chemical ecology, phenotypic plasticity, and food webs. ANNUAL REVIEW OF ENTOMOLOGY 2015; 60:213-32. [PMID: 25564741 DOI: 10.1146/annurev-ento-010814-020753] [Citation(s) in RCA: 69] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
Plants secrete extrafloral nectar (EFN) as an induced defense against herbivores. EFN contains not only carbohydrates and amino acids but also pathogenesis-related proteins and other protective enzymes, making EFN an exclusive reward. EFN secretion is commonly induced after wounding, likely owing to a jasmonic acid-induced cell wall invertase, and is limited by phloem sucrose availability: Both factors control EFN secretion according to the optimal defense hypothesis. Non-ant EFN consumers include parasitoids, wasps, spiders, mites, bugs, and predatory beetles. Little is known about the relevance of EFN to the nutrition of its consumers and, hence, to the structuring of arthropod communities. The mutualism can be established quickly among noncoevolved (e.g., invasive) species, indicating its easy assembly is due to ecological fitting. Therefore, increasing efforts are directed toward using EFN in biocontrol. However, documentation of the importance of EFN for the communities of plants and arthropods in natural, invasive, and agricultural ecosystems is still limited.
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Affiliation(s)
- Martin Heil
- Departamento de Ingeniería Genética, CINVESTAV-Irapuato, 36821 Irapuato, Guanajuato, México;
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Jones IM, Koptur S. Dynamic extrafloral nectar production: the timing of leaf damage affects the defensive response in Senna mexicana var. chapmanii (Fabaceae). AMERICAN JOURNAL OF BOTANY 2015; 102:58-66. [PMID: 25587148 DOI: 10.3732/ajb.1400381] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
UNLABELLED • PREMISE OF THE STUDY Extrafloral nectar (EFN) mediates food for protection mutualisms between plants and defensive insects. Understanding sources of variation in EFN production is important because such variations may affect the number and identity of visitors and the effectiveness of plant defense. We investigated the influence of plant developmental stage, time of day, leaf age, and leaf damage on EFN production in Senna mexicana var. chapmanii. The observed patterns of variation in EFN production were compared with those predicted by optimal defense theory.• METHODS Greenhouse experiments with potted plants were conducted to determine how plant age, time of day, and leaf damage affected EFN production. A subsequent field study was conducted to determine how leaf damage, and the resulting increase in EFN production, affected ant visitation in S. chapmanii.• KEY RESULTS More nectar was produced at night and by older plants. Leaf damage resulted in increased EFN production, and the magnitude of the response was greater in plants damaged in the morning than those damaged at night. Damage to young leaves elicited a stronger defensive response than damage to older leaves, in line with optimal defense theory. Damage to the leaves of S. chapmanii also resulted in significantly higher ant visitation in the field.• CONCLUSIONS Extrafloral nectar is an inducible defense in S. chapmanii. Developmental variations in its production support the growth differentiation balance hypothesis, while within-plant variations and damage responses support optimal defense theory.
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Affiliation(s)
- Ian M Jones
- Department of Biological Sciences, Florida International University 11200 S.W. 8th Street, Miami, Florida 33199 USA
| | - Suzanne Koptur
- Department of Biological Sciences, Florida International University 11200 S.W. 8th Street, Miami, Florida 33199 USA
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Aranda-Rickert A, Diez P, Marazzi B. Extrafloral nectar fuels ant life in deserts. AOB PLANTS 2014; 6:plu068. [PMID: 25381258 PMCID: PMC4262941 DOI: 10.1093/aobpla/plu068] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
Interactions mediated by extrafloral nectary (EFN)-bearing plants that reward ants with a sweet liquid secretion are well documented in temperate and tropical habitats. However, their distribution and abundance in deserts are poorly known. In this study, we test the predictions that biotic interactions between EFN plants and ants are abundant and common also in arid communities and that EFNs are only functional when new vegetative and reproductive structures are developing. In a seasonal desert of northwestern Argentina, we surveyed the richness and phenology of EFN plants and their associated ants and examined the patterns in ant-plant interaction networks. We found that 25 ant species and 11 EFN-bearing plant species were linked together through 96 pairs of associations. Plants bearing EFNs were abundant, representing ca. 19 % of the species encountered in transects and 24 % of the plant cover. Most ant species sampled (ca. 77 %) fed on EF nectar. Interactions showed a marked seasonal pattern: EFN secretion was directly related to plant phenology and correlated with the time of highest ant ground activity. Our results reveal that EFN-mediated interactions are ecologically relevant components of deserts, and that EFN-bearing plants are crucial for the survival of desert ant communities.
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Affiliation(s)
- Adriana Aranda-Rickert
- Centro Regional de Investigaciones Científicas y Transferencia Tecnológica de La Rioja-CRILAR-(CONICET), Entre Ríos y Mendoza s/n, 5301 Anillaco, La Rioja, Argentina
| | - Patricia Diez
- Centro Regional de Investigaciones Científicas y Transferencia Tecnológica de La Rioja-CRILAR-(CONICET), Entre Ríos y Mendoza s/n, 5301 Anillaco, La Rioja, Argentina
| | - Brigitte Marazzi
- Facultad de Ciencias Agrarias, Instituto de Botánica del Nordeste-IBONE-(UNNE-CONICET), Sgto. Cabral 2131, 3400 Corrientes, Argentina
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Ant-plant interaction in a tropical savanna: may the network structure vary over time and influence on the outcomes of associations? PLoS One 2014; 9:e105574. [PMID: 25141007 PMCID: PMC4139372 DOI: 10.1371/journal.pone.0105574] [Citation(s) in RCA: 54] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2014] [Accepted: 07/21/2014] [Indexed: 11/19/2022] Open
Abstract
Plant-animal interactions occur in a community context of dynamic and complex ecological interactive networks. The understanding of who interacts with whom is a basic information, but the outcomes of interactions among associates are fundamental to draw valid conclusions about the functional structure of the network. Ecological networks studies in general gave little importance to know the true outcomes of interactions and how they may change over time. We evaluate the dynamic of an interaction network between ants and plants with extrafloral nectaries, by verifying the temporal variation in structure and outcomes of mutualism for the plant community (leaf herbivory). To reach this goal, we used two tools: bipartite network analysis and experimental manipulation. The networks exhibited the same general pattern as other mutualistic networks: nestedness, asymmetry and low specialization and this pattern was maintained over time, but with internal changes (species degree, connectance and ant abundance). These changes influenced the protection effectiveness of plants by ants, which varied over time. Our study shows that interaction networks between ants and plants are dynamic over time, and that these alterations affect the outcomes of mutualisms. In addition, our study proposes that the set of single systems that shape ecological networks can be manipulated for a greater understanding of the entire system.
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Mayer VE, Frederickson ME, McKey D, Blatrix R. Current issues in the evolutionary ecology of ant-plant symbioses. THE NEW PHYTOLOGIST 2014; 202:749-764. [PMID: 24444030 DOI: 10.1111/nph.12690] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/24/2013] [Accepted: 12/16/2013] [Indexed: 05/08/2023]
Abstract
Ant-plant symbioses involve plants that provide hollow structures specialized for housing ants and often food to ants. In return, the inhabiting ants protect plants against herbivores and sometimes provide them with nutrients. Here, we review recent advances in ant-plant symbioses, focusing on three areas. First, the nutritional ecology of plant-ants, which is based not only on plant-derived food rewards, but also on inputs from other symbiotic partners, in particular fungi and possibly bacteria. Food and protection are the most important 'currencies' exchanged between partners and they drive the nature and evolution of the relationships. Secondly, studies of conflict and cooperation in ant-plant symbioses have contributed key insights into the evolution and maintenance of mutualism, particularly how partner-mediated feedbacks affect the specificity and stability of mutualisms. There is little evidence that mutualistic ants or plants are under selection to cheat, but the costs and benefits of ant-plant interactions do vary with environmental factors, making them vulnerable to natural or anthropogenic environmental change. Thus, thirdly, ant-plant symbioses should be considered good models for investigating the effects of global change on the outcome of mutualistic interactions.
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Affiliation(s)
- Veronika E Mayer
- Department of Structural and Functional Botany, Faculty Centre of Biodiversity, University of Vienna, Rennweg 14, A-1030, Wien, Austria
| | - Megan E Frederickson
- Department of Ecology & Evolutionary Biology, University of Toronto, 25 Harbord Street, Toronto, M5S 3G5, Canada
| | - Doyle McKey
- Centre d'Ecologie Fonctionnelle et Evolutive, UMR 5175 CEFE, Université Montpellier 2, 1919 route de Mende, 34293, Montpellier Cedex 5, France
- Institut Universitaire de France, Université Montpellier 2, Montpellier Cedex 5, France
| | - Rumsaïs Blatrix
- Centre d'Ecologie Fonctionnelle et Evolutive, UMR 5175 CEFE, CNRS, 1919 route de Mende, 34293, Montpellier Cedex 5, France
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Orona-Tamayo D, Heil M. Stabilizing Mutualisms Threatened by Exploiters: New Insights from Ant-Plant Research. Biotropica 2013. [DOI: 10.1111/btp.12059] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Affiliation(s)
- Domancar Orona-Tamayo
- Departamento de Ingeniería Genética; CINVESTAV-Irapuato; Irapuato Guanajuato Mexico
- Instituto de Investigaciones Químico-Biológicas; Universidad Michoacana de San Nicolás de Hidalgo (UMSNH); Edif. B3, Ciudad Universitaria 58060 Morelia Michoacán Mexico
| | - Martin Heil
- Departamento de Ingeniería Genética; CINVESTAV-Irapuato; Irapuato Guanajuato Mexico
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Marazzi B, Bronstein JL, Koptur S. The diversity, ecology and evolution of extrafloral nectaries: current perspectives and future challenges. ANNALS OF BOTANY 2013; 111:1243-50. [PMID: 23704115 PMCID: PMC3662527 DOI: 10.1093/aob/mct109] [Citation(s) in RCA: 78] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
BACKGROUND Plants in over one hundred families in habitats worldwide bear extrafloral nectaries (EFNs). EFNs display a remarkable diversity of evolutionary origins, as well as diverse morphology and location on the plant. They secrete extrafloral nectar, a carbohydrate-rich food that attracts ants and other arthropods, many of which protect the plant in return. By fostering ecologically important protective mutualisms, EFNs play a significant role in structuring both plant and animal communities. And yet researchers are only now beginning to appreciate their importance and the range of ecological, evolutionary and morphological diversity that EFNs exhibit. SCOPE This Highlight features a series of papers that illustrate some of the newest directions in the study of EFNs. Here, we introduce this set of papers by providing an overview of current understanding and new insights on EFN diversity, ecology and evolution. We highlight major gaps in our current knowledge, and outline future research directions. CONCLUSIONS Our understanding of the roles EFNs play in plant biology is being revolutionized with the use of new tools from developmental biology and genomics, new modes of analysis allowing hypothesis-testing in large-scale phylogenetic frameworks, and new levels of inquiry extending to community-scale interaction networks. But many central questions remain unanswered; indeed, many have not yet been asked. Thus, the EFN puzzle remains an intriguing challenge for the future.
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Affiliation(s)
- Brigitte Marazzi
- Department of Ecology and Evolutionary Biology, University of Arizona, Tucson, AZ 85721, USA.
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Savage AM, Rudgers JA. Non-additive benefit or cost? Disentangling the indirect effects that occur when plants bearing extrafloral nectaries and honeydew-producing insects share exotic ant mutualists. ANNALS OF BOTANY 2013; 111:1295-307. [PMID: 23609021 PMCID: PMC3662523 DOI: 10.1093/aob/mct082] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
BACKGROUND AND AIMS In complex communities, organisms often form mutualisms with multiple different partners simultaneously. Non-additive effects may emerge among species linked by these positive interactions. Ants commonly participate in mutualisms with both honeydew-producing insects (HPI) and their extrafloral nectary (EFN)-bearing host plants. Consequently, HPI and EFN-bearing plants may experience non-additive benefits or costs when these groups co-occur. The outcomes of these interactions are likely to be influenced by variation in preferences among ants for honeydew vs. nectar. In this study, a test was made for non-additive effects on HPI and EFN-bearing plants resulting from sharing exotic ant guards. Preferences of the dominant exotic ant species for nectar vs. honeydew resources were also examined. METHODS Ant access, HPI and nectar availability were manipulated on the EFN-bearing shrub, Morinda citrifolia, and ant and HPI abundances, herbivory and plant growth were assessed. Ant-tending behaviours toward HPI across an experimental gradient of nectar availability were also tracked in order to investigate mechanisms underlying ant responses. KEY RESULTS The dominant ant species, Anoplolepis gracilipes, differed from less invasive ants in response to multiple mutualists, with reductions in plot-wide abundances when nectar was reduced, but no response to HPI reduction. Conversely, at sites where A. gracilipes was absent or rare, abundances of less invasive ants increased when nectar was reduced, but declined when HPI were reduced. Non-additive benefits were found at sites dominated by A. gracilipes, but only for M. citrifolia plants. Responses of HPI at these sites supported predictions of the non-additive cost model. Interestingly, the opposite non-additive patterns emerged at sites dominated by other ants. CONCLUSIONS It was demonstrated that strong non-additive benefits and costs can both occur when a plant and herbivore share mutualist partners. These findings suggest that broadening the community context of mutualism studies can reveal important non-additive effects and increase understanding of the dynamics of species interactions.
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Affiliation(s)
- Amy M Savage
- Department of Biology, North Carolina State University, Raleigh, NC 27607, USA.
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Rudolph KP, Palmer TM. Carbohydrate as Fuel for Foraging, Resource Defense and Colony Growth - a Long-term Experiment with the Plant-antCrematogaster nigriceps. Biotropica 2013. [DOI: 10.1111/btp.12040] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Mathur V, Wagenaar R, Caissard JC, Reddy AS, Vet LEM, Cortesero AM, Van Dam NM. A novel indirect defence in Brassicaceae: structure and function of extrafloral nectaries in Brassica juncea. PLANT, CELL & ENVIRONMENT 2013; 36:528-41. [PMID: 22889298 DOI: 10.1111/j.1365-3040.2012.02593.x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
While nectaries are commonly found in flowers, some plants also form extrafloral nectaries on stems or leaves. For the first time in the family Brassicaceae, here we report extrafloral nectaries in Brassica juncea. The extrafloral nectar (EFN) was secreted from previously amorphic sites on stems, flowering stalks and leaf axils from the onset of flowering until silique formation. Transverse sections at the point of nectar secretion revealed a pocket-like structure whose opening was surrounded by modified stomatal guard cells. The EFN droplets were viscous and up to 50% of the total weight was sugars, 97% of which was sucrose in the five varieties of B. juncea examined. Threonine, glutamine, arginine and glutamate were the most abundant amino acids. EFN droplets also contained glucosinolates, mainly gluconapin and sinigrin. Nectar secretion was increased when the plants were damaged by chewing above- and belowground herbivores and sap-sucking aphids. Parasitoids of each herbivore species were tested for their preference, of which three parasitoids preferred EFN and sucrose solutions over water. Moreover, the survival and fecundity of parasitoids were positively affected by feeding on EFN. We conclude that EFN production in B. juncea may contribute to the indirect defence of this plant species.
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Affiliation(s)
- Vartika Mathur
- Department of Terrestrial Ecology, Netherlands Institute of Ecology (NIOO-KNAW), PO Box 50, 6700 AB Wageningen, The Netherlands.
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Ness JH, Morales MA, Kenison E, Leduc E, Leipzig-Scott P, Rollinson E, Swimm BJ, von Allmen DR. Reciprocally beneficial interactions between introduced plants and ants are induced by the presence of a third introduced species. OIKOS 2012. [DOI: 10.1111/j.1600-0706.2012.20212.x] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Affiliation(s)
- Martin Heil
- Departamento de Ingeniería Genética; CINVESTAV; Irapuato; México
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Ant Larval Demand Reduces Aphid Colony Growth Rates in an Ant-Aphid Interaction. INSECTS 2012; 3:120-30. [PMID: 26467951 PMCID: PMC4553619 DOI: 10.3390/insects3010120] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/13/2011] [Revised: 01/06/2012] [Accepted: 01/11/2012] [Indexed: 11/16/2022]
Abstract
Ants often form mutualistic interactions with aphids, soliciting honeydew in return for protective services. Under certain circumstances, however, ants will prey upon aphids. In addition, in the presence of ants aphids may increase the quantity or quality of honeydew produced, which is costly. Through these mechanisms, ant attendance can reduce aphid colony growth rates. However, it is unknown whether demand from within the ant colony can affect the ant-aphid interaction. In a factorial experiment, we tested whether the presence of larvae in Lasius niger ant colonies affected the growth rate of Aphis fabae colonies. Other explanatory variables tested were the origin of ant colonies (two separate colonies were used) and previous diet (sugar only or sugar and protein). We found that the presence of larvae in the ant colony significantly reduced the growth rate of aphid colonies. Previous diet and colony origin did not affect aphid colony growth rates. Our results suggest that ant colonies balance the flow of two separate resources from aphid colonies- renewable sugars or a protein-rich meal, depending on demand from ant larvae within the nest. Aphid payoffs from the ant-aphid interaction may change on a seasonal basis, as the demand from larvae within the ant colony waxes and wanes.
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Nectar Secretion: Its Ecological Context and Physiological Regulation. SIGNALING AND COMMUNICATION IN PLANTS 2012. [DOI: 10.1007/978-3-642-23047-9_9] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
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Heil M. Nectar: generation, regulation and ecological functions. TRENDS IN PLANT SCIENCE 2011; 16:191-200. [PMID: 21345715 DOI: 10.1016/j.tplants.2011.01.003] [Citation(s) in RCA: 260] [Impact Index Per Article: 20.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/30/2010] [Revised: 01/05/2011] [Accepted: 01/14/2011] [Indexed: 05/23/2023]
Abstract
Nectar contains water, sugars and amino acids to attract pollinators and defenders and is protected from nectar robbers and microorganisms by secondary compounds and antimicrobial proteins. Floral and extrafloral nectar secretion can be induced by jasmonic acid, it is often adjusted to consumer identity and consumption rate and depends on invertase activity. Invertases are likely to play at least three roles: the uploading of sucrose from the phloem, carbohydrate mobilization during active secretion and the postsecretory adjustment of the sucrose:hexose ratio of nectar. However, it remains to be studied how plants produce and secrete non-carbohydrate components. More research is needed to understand how plants produce nectar, the most important mediator of their interactions with mutualistic animals.
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Affiliation(s)
- Martin Heil
- Departamento de Ingeniería Genética, CINVESTAV - Irapuato, Km. 9.6 Libramiento Norte, CP 36821, Irapuato, Guanajuato, México.
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Gaigher R, Samways MJ, Henwood J, Jolliffe K. Impact of a mutualism between an invasive ant and honeydew-producing insects on a functionally important tree on a tropical island. Biol Invasions 2011. [DOI: 10.1007/s10530-010-9934-1] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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Lach L, Hoffmann BD. Are invasive ants better plant-defense mutualists? A comparison of foliage patrolling and herbivory in sites with invasive yellow crazy ants and native weaver ants. OIKOS 2010. [DOI: 10.1111/j.1600-0706.2010.18803.x] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Ant–plant interaction in the Neotropical savanna: direct beneficial effects of extrafloral nectar on ant colony fitness. POPUL ECOL 2010. [DOI: 10.1007/s10144-010-0240-7] [Citation(s) in RCA: 60] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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