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Fruit secondary metabolites shape seed dispersal effectiveness. Trends Ecol Evol 2021; 36:1113-1123. [PMID: 34509316 DOI: 10.1016/j.tree.2021.08.005] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2021] [Revised: 08/05/2021] [Accepted: 08/09/2021] [Indexed: 11/22/2022]
Abstract
Plant secondary metabolites (PSMs) play a central role in seed dispersal and fruit defense, with potential for large impacts on plant fitness and demography. Yet because PSMs can have multiple interactive functions across seed dispersal stages, we must systematically study their effects to determine the net consequences for plant fitness. To tackle this issue, we integrate the role of fruit PSMs into the seed dispersal effectiveness (SDE) framework. We describe PSM effects on the quantity and quality of animal-mediated seed dispersal, both in pairwise interactions and diverse disperser communities, as well as trade-offs that occur across dispersal stages. By doing so, this review provides structure to a rapidly growing field and yields insights into a critical process shaping plant populations.
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Bartel SL, Orrock JL. An omnivorous mesopredator modifies predation of omnivore‐dispersed seeds. Ecosphere 2021. [DOI: 10.1002/ecs2.3369] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Affiliation(s)
- Savannah L. Bartel
- University of Wisconsin – Madison 363 Birge Hall, 430 Lincoln Drive Madison Wisconsin53706USA
| | - John L. Orrock
- University of Wisconsin – Madison 363 Birge Hall, 430 Lincoln Drive Madison Wisconsin53706USA
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3
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Miller CN, Whitehead SR, Kwit C. Effects of seed morphology and elaiosome chemical composition on attractiveness of five Trillium species to seed-dispersing ants. Ecol Evol 2020; 10:2860-2873. [PMID: 32211161 PMCID: PMC7083703 DOI: 10.1002/ece3.6101] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2019] [Revised: 01/18/2020] [Accepted: 01/27/2020] [Indexed: 12/23/2022] Open
Abstract
Morphological and chemical attributes of diaspores in myrmecochorous plants have been shown to affect seed dispersal by ants, but the relative importance of these attributes in determining seed attractiveness and dispersal success is poorly understood. We explored whether differences in diaspore morphology, elaiosome fatty acids, or elaiosome phytochemical profiles explain the differential attractiveness of five species in the genus Trillium to eastern North American forest ants. Species were ranked from least to most attractive based on empirically-derived seed dispersal probabilities in our study system, and we compared diaspore traits to test our hypotheses that more attractive species will have larger diaspores, greater concentrations of elaiosome fatty acids, and distinct elaiosome phytochemistry compared to the less attractive species. Diaspore length, width, mass, and elaiosome length were significantly greater in the more attractive species. Using gas chromatography-mass spectrometry, we found significantly higher concentrations of oleic, linoleic, hexadecenoic, stearic, palmitoleic, and total fatty acids in elaiosomes of the more attractive species. Multivariate assessments revealed that elaiosome phytochemical profiles, identified through liquid chromatography-mass spectrometry, were more homogeneous for the more attractive species. Random forest classification models (RFCM) identified several elaiosome phytochemicals that differed significantly among species. Random forest regression models revealed that some of the compounds identified by RFCM, including methylhistidine (α-amino acid) and d-glucarate (carbohydrate), were positively related to seed dispersal probabilities, while others, including salicylate (salicylic acid) and citrulline (L-α-amino acid), were negatively related. These results supported our hypotheses that the more attractive species of Trillium-which are geographically widespread compared to their less attractive, endemic congeners-are characterized by larger diaspores, greater concentrations of fatty acids, and distinct elaiosome phytochemistry. Further advances in our understanding of seed dispersal effectiveness in myrmecochorous systems will benefit from a portrayal of dispersal unit chemical and physical traits, and their combined responses to selection pressures.
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Affiliation(s)
- Chelsea N. Miller
- Department of Ecology and Evolutionary BiologyUniversity of TennesseeKnoxvilleTNUSA
| | - Susan R. Whitehead
- Department of Biological SciencesVirginia Tech UniversityBlacksburgVAUSA
| | - Charles Kwit
- Department of Ecology and Evolutionary BiologyUniversity of TennesseeKnoxvilleTNUSA
- Department of Forestry, Wildlife and FisheriesUniversity of TennesseeKnoxvilleTNUSA
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Schupp EW, Zwolak R, Jones LR, Snell RS, Beckman NG, Aslan C, Cavazos BR, Effiom E, Fricke EC, Montaño-Centellas F, Poulsen J, Razafindratsima OH, Sandor ME, Shea K. Intrinsic and extrinsic drivers of intraspecific variation in seed dispersal are diverse and pervasive. AOB PLANTS 2019; 11:plz067. [PMID: 31857875 PMCID: PMC6914678 DOI: 10.1093/aobpla/plz067] [Citation(s) in RCA: 34] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/25/2019] [Accepted: 10/09/2019] [Indexed: 05/23/2023]
Abstract
There is growing realization that intraspecific variation in seed dispersal can have important ecological and evolutionary consequences. However, we do not have a good understanding of the drivers or causes of intraspecific variation in dispersal, how strong an effect these drivers have, and how widespread they are across dispersal modes. As a first step to developing a better understanding, we present a broad, but not exhaustive, review of what is known about the drivers of intraspecific variation in seed dispersal, and what remains uncertain. We start by decomposing 'drivers of intraspecific variation in seed dispersal' into intrinsic drivers (i.e. variation in traits of individual plants) and extrinsic drivers (i.e. variation in ecological context). For intrinsic traits, we further decompose intraspecific variation into variation among individuals and variation of trait values within individuals. We then review our understanding of the major intrinsic and extrinsic drivers of intraspecific variation in seed dispersal, with an emphasis on variation among individuals. Crop size is the best-supported and best-understood intrinsic driver of variation across dispersal modes; overall, more seeds are dispersed as more seeds are produced, even in cases where per seed dispersal rates decline. Fruit/seed size is the second most widely studied intrinsic driver, and is also relevant to a broad range of seed dispersal modes. Remaining intrinsic drivers are poorly understood, and range from effects that are probably widespread, such as plant height, to drivers that are most likely sporadic, such as fruit or seed colour polymorphism. Primary extrinsic drivers of variation in seed dispersal include local environmental conditions and habitat structure. Finally, we present a selection of outstanding questions as a starting point to advance our understanding of individual variation in seed dispersal.
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Affiliation(s)
- Eugene W Schupp
- Department of Wildland Resources and Ecology Center, Utah State University, Logan, UT, USA
| | - Rafal Zwolak
- Department of Systematic Zoology, Adam Mickiewicz University, Poznań, Poland
| | - Landon R Jones
- Department of Forestry and Natural Resources, Purdue University, West Lafayette, IN, USA
| | - Rebecca S Snell
- Environmental and Plant Biology, Ohio University, Athens, OH, USA
| | - Noelle G Beckman
- Department of Biology and Ecology Center, Utah State University, Logan, UT, USA
| | - Clare Aslan
- Landscape Conservation Initiative, Northern Arizona University, Flagstaff, AZ, USA
| | - Brittany R Cavazos
- Department of Ecology, Evolution and Organismal Biology, Iowa State University, Ames, IA, USA
| | - Edu Effiom
- REDD & Biodiversity Unit, Cross River State Forestry Commission, Calabar, Nigeria
| | - Evan C Fricke
- National Socio-Environmental Synthesis Center, University of Maryland, Annapolis, MD, USA
| | | | - John Poulsen
- Nicholas School of the Environment, Duke University, Durham, NC, USA
| | - Onja H Razafindratsima
- Department of Natural Resource Management, South Dakota State University, Brookings, SD, USA
| | - Manette E Sandor
- Department of Ecology, Evolution, and Environmental Biology, Columbia University, New York, NY, USA
- Center for Biodiversity and Conservation, American Museum of Natural History, New York, NY, USA
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Moreno-Ramírez YDR, Martínez-Ávila GCG, González-Hernández VA, Castro-López C, Torres-Castillo JA. Free Radical-Scavenging Capacities, Phenolics and Capsaicinoids in Wild Piquin Chili ( Capsicum annuum var. Glabriusculum). Molecules 2018; 23:E2655. [PMID: 30332792 PMCID: PMC6222680 DOI: 10.3390/molecules23102655] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2018] [Revised: 10/07/2018] [Accepted: 10/11/2018] [Indexed: 01/18/2023] Open
Abstract
The total phenolic compounds content, free radical-scavenging capacity and capsaicinoid content in populations of wild Piquin chili (C. annuum) were studied. Aqueous and hydroalcoholic extracts from nine ecotypes were evaluated. High contents of phenolic compounds and free radical-scavenging capacities were observed for both extracts; however, the values that were found for the hydroalcoholic phase were substantially higher. LC-MS analysis allowed for the detection of 32 compounds, where apigenin-8-C-glucoside followed by vanillic acid 1-O-β-o-glucopyranosylester (Isomer I or II) and 7-ethoxy-4-methylcoumarin were the most widely distributed; they were found in more than 89% of the ecotypes. The diversity of identified phenolic compounds was different among ecotypes, allowing them to be distinguished by chemical diversity, free radical-scavenging capacities and heat Scoville units. The total capsaicinoid content was higher in Population I (23.5 mg/g DW) than in Populations II and III, which had contents of 15.3 and 10.7 mg/g DW, respectively. This variability could lead to phytochemical exploitation and the conservation of the natural populations of wild chili.
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Affiliation(s)
- Yolanda Del Rocio Moreno-Ramírez
- Institute of Applied Ecology, Autonomous University of Tamaulipas, Gulf Division 356, Ciudad Victoria, 87019 Tamaulipas, Mexico.
| | - Guillermo C G Martínez-Ávila
- Laboratory of Chemistry and Biochemistry, School of Agronomy, Autonomous University of Nuevo Leon, General Escobedo, 66050 Nuevo Leon, Mexico.
| | - Víctor Arturo González-Hernández
- Posgrado de Recursos Genéticos y Productividad-Fisiología Vegetal, Colegio de Postgraduados, Texcoco, 56230 Estado de Mexico, Mexico.
| | - Cecilia Castro-López
- Laboratory of Chemistry and Biochemistry, School of Agronomy, Autonomous University of Nuevo Leon, General Escobedo, 66050 Nuevo Leon, Mexico.
| | - Jorge Ariel Torres-Castillo
- Institute of Applied Ecology, Autonomous University of Tamaulipas, Gulf Division 356, Ciudad Victoria, 87019 Tamaulipas, Mexico.
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Guerra TJ, Messeder JVS, Arruda AJ, Fuzessy LF, Dayrell RLC, Neves FS, Silveira FAO. Handling by avian frugivores affects diaspore secondary removal. PLoS One 2018; 13:e0202435. [PMID: 30157261 PMCID: PMC6114891 DOI: 10.1371/journal.pone.0202435] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2018] [Accepted: 08/02/2018] [Indexed: 11/19/2022] Open
Abstract
The balance between the costs and benefits of fleshy fruit production depends on the feeding behavior of their seed dispersers, which might effectively disperse seeds to farther areas or drop beneath parent plants some diaspores they handle during frugivory bouts. Nevertheless, the consequences of variation in fruit handling by primary seed dispersers on the secondary removal of diaspores remains poorly understood. We conducted a field study to determine how variation in fruit handling by avian frugivores affects short-term secondary removal of Miconia irwinii (Melastomataceae) diaspores by the ground-dwelling fauna in campo rupestre vegetation, southeastern Brazil. We conducted factorial experiments manipulating: (1) different outcomes of primary fruit/seed removal by birds, (2) distances of diaspore deposition from conspecifics, and (3) the access of ants and vertebrates to diaspores. We showed that secondary removal of diaspores was highly variable at the population scale, with an overall low removal rate by the ground-dwelling fauna (13% seeds, 19% fruits). However, we found that gut-passed seeds embedded in bird feces were less removed than seeds expelled from fruits. Gut-passed seeds were more likely to be removed by ant species acting as secondary dispersers, whereas pulp-free seeds dropped by birds were likely to interact with potential seed predators, including ants and rodents. We found no clear effect of dispersal from parent plant vicinity on seed removal, but fruit removal was significantly higher near parent plants. Partially defleshed fruits were more removed than intact fruits. The removal of fruits by ant and vertebrate rescuers, including lizards and birds, might reduce the costs of interactions with less effective dispersers that drop partially defleshed fruits under parent plants. Our study highlights that variation in fruit handling by primary avian seed dispersers mediate subsequent interactions among discarded diaspores and ground-dwelling animals, potentially affecting final seed fates. Moreover, we argue that escape-related benefits of dispersal can be contingent on how primary dispersers handle and discard seeds.
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Affiliation(s)
- Tadeu J. Guerra
- Departamento de Botânica, Universidade Federal de Minas Gerais—Belo Horizonte, Brazil
- * E-mail:
| | - João V. S. Messeder
- Departamento de Botânica, Universidade Federal de Minas Gerais—Belo Horizonte, Brazil
| | - André J. Arruda
- Departamento de Botânica, Universidade Federal de Minas Gerais—Belo Horizonte, Brazil
| | - Lisieux F. Fuzessy
- Departamento de Botânica, Universidade Federal de Minas Gerais—Belo Horizonte, Brazil
| | - Roberta L. C. Dayrell
- Departamento de Botânica, Universidade Federal de Minas Gerais—Belo Horizonte, Brazil
| | - Frederico S. Neves
- Departamento de Biologia Geral, Universidade Federal de Minas Gerais—Belo Horizonte, Brazil
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Egerer MH, Fricke EC, Rogers HS. Seed dispersal as an ecosystem service: frugivore loss leads to decline of a socially valued plant, Capsicum frutescens. ECOLOGICAL APPLICATIONS : A PUBLICATION OF THE ECOLOGICAL SOCIETY OF AMERICA 2018; 28:655-667. [PMID: 29271019 PMCID: PMC5947168 DOI: 10.1002/eap.1667] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/16/2017] [Revised: 11/09/2017] [Accepted: 11/28/2017] [Indexed: 06/07/2023]
Abstract
Species interactions, both mutualistic and antagonistic, are widely recognized as providing important ecosystem services. Fruit-eating animals influence plant recruitment by increasing germination during gut passage and moving seeds away from conspecifics. However, relative to studies focused on the importance of frugivores for plant population maintenance, few studies target frugivores as ecosystem service providers, and frugivores are underappreciated as ecosystem service providers relative to other mutualists such as pollinators. Here, we use an accidental experiment to elucidate the role of seed dispersal by frugivores for maintaining a culturally and economically important plant, the donne' sali chili (Capsicum frutescens) in the Mariana Islands. One of the islands (Guam) has lost nearly all of its native forest birds due to an invasive snake (Boiga irregularis), whereas nearby islands have relatively intact bird populations. We hypothesized that frugivore loss would influence chili recruitment and abundance, which could have economic and cultural impacts. By using video cameras, we confirmed that birds were the primary seed dispersers. We used captive bird feeding trials to obtain gut-passed seeds to use in a seedling emergence experiment. The experiment showed that gut-passed seeds emerged sooner and at a higher proportion than seeds from whole fruits. Consistent with our findings that birds benefit chilies, we observed lower chili abundance on Guam than on islands with birds. In a survey questionnaire of island residents, the majority of residents reported an association between the wild chili and local cultural values and traditions. In addition, we identified a thriving market for chili products, suggesting benefits of wild chilies to people in the Marianas both as consumers and producers. Our study therefore documents seed dispersal as both a cultural and a supporting ecosystem service. We provide a comprehensive case study on how seed-dispersed plants decline in the absence of their disperser, and how to apply mixed-methods in ecosystem service assessments. Furthermore, we suggest that scientists and resource managers may utilize fruit-frugivore mutualisms concerning socially valuable plants to gather support for frugivore and forest conservation efforts.
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Affiliation(s)
- Monika H. Egerer
- Department of Environmental StudiesUniversity of California1156 High Street, Mailstop: ENVSSanta CruzCalifornia95064USA
| | - Evan C. Fricke
- Department of Ecology, Evolution and Organismal BiologyIowa State University251 Bessey HallAmesIowa50011USA
| | - Haldre S. Rogers
- Department of Ecology, Evolution and Organismal BiologyIowa State University251 Bessey HallAmesIowa50011USA
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