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Gontijo LM. Addressing context dependence in studies of plant diversity to improve the understanding of natural enemy conservation. CURRENT OPINION IN INSECT SCIENCE 2024; 63:101202. [PMID: 38642848 DOI: 10.1016/j.cois.2024.101202] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/26/2023] [Revised: 04/05/2024] [Accepted: 04/12/2024] [Indexed: 04/22/2024]
Abstract
Increasing plant diversity has become a major aspect of habitat management and natural enemy conservation. Nonetheless, the results of plant diversity studies have varied significantly within and across agroecosystems. This variation has often been ascribed to a condition known as context dependence. However, concluding plainly that results are context dependent does not allow for the understanding of the actual underlying causes. Therefore, I discuss in this paper the importance of identifying and dealing with context dependence. I specifically comment on common biotic and abiotic inherent variables that can drive context dependence. The most common context types explored herein are location, time, nonfocal plant and crop species, and natural enemy species. Finally, I offer several recommendations for identifying and dealing with context dependence. I believe understanding the different forms in which context dependence arises is paramount to reduce unexplained variation and improve the predictability of plant diversity studies.
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Affiliation(s)
- Lessando M Gontijo
- Department of Entomology and Acarology, Luiz de Queiroz College of Agriculture, University of São Paulo, Piracicaba, SP 13418-900, Brazil.
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Balakrishnan D, Bateman N, Kariyat RR. Rice physical defenses and their role against insect herbivores. PLANTA 2024; 259:110. [PMID: 38565704 PMCID: PMC10987372 DOI: 10.1007/s00425-024-04381-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/11/2023] [Accepted: 03/07/2024] [Indexed: 04/04/2024]
Abstract
MAIN CONCLUSION Understanding surface defenses, a relatively unexplored area in rice can provide valuable insight into constitutive and induced defenses against herbivores. Plants have evolved a multi-layered defense system against the wide range of pests that constantly attack them. Physical defenses comprised of trichomes, wax, silica, callose, and lignin, and are considered as the first line of defense against herbivory that can directly affect herbivores by restricting or deterring them. Most studies on physical defenses against insect herbivores have been focused on dicots compared to monocots, although monocots include one of the most important crops, rice, which half of the global population is dependent on as their staple food. In rice, Silica is an important element stimulating plant growth, although Silica has also been found to impart resistance against herbivores. However, other physical defenses in rice including wax, trichomes, callose, and lignin are less explored. A detailed exploration of the morphological structures and functional consequences of physical defense structures in rice can assist in incorporating these resistance traits in plant breeding and genetic improvement programs, and thereby potentially reduce the use of chemicals in the field. This mini review addresses these points with a closer look at current literature and prospects on rice physical defenses.
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Affiliation(s)
- Devi Balakrishnan
- Department of Entomology and Plant Pathology, University of Arkansas, Fayetteville, AR, 72701, USA
| | - Nick Bateman
- Department of Entomology and Plant Pathology, University of Arkansas, Fayetteville, AR, 72701, USA
| | - Rupesh R Kariyat
- Department of Entomology and Plant Pathology, University of Arkansas, Fayetteville, AR, 72701, USA.
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Staab M, Pietsch S, Yan H, Blüthgen N, Cheng A, Li Y, Zhang N, Ma K, Liu X. Dear neighbor: Trees with extrafloral nectaries facilitate defense and growth of adjacent undefended trees. Ecology 2023; 104:e4057. [PMID: 37078562 DOI: 10.1002/ecy.4057] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/08/2022] [Revised: 03/22/2023] [Accepted: 04/11/2023] [Indexed: 04/21/2023]
Abstract
Plant diversity can increase productivity. One mechanism behind this biodiversity effect is facilitation, which is when one species increases the performance of another species. Plants with extrafloral nectaries (EFNs) establish defense mutualisms with ants. However, whether EFN plants facilitate defense of neighboring non-EFN plants is unknown. Synthesizing data on ants, herbivores, leaf damage, and defense traits from a forest biodiversity experiment, we show that trees growing adjacent to EFN trees had higher ant biomass and species richness and lower caterpillar biomass than conspecific controls without EFN-bearing neighbors. Concurrently, the composition of defense traits in non-EFN trees changed. Thus, when non-EFN trees benefit from lower herbivore loads as a result of ants spilling over from EFN tree neighbors, this may allow relatively reduced resource allocation to defense in the former, potentially explaining the higher growth of those trees. Via this mutualist-mediated facilitation, promoting EFN trees in tropical reforestation could foster carbon capture and multiple other ecosystem functions.
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Affiliation(s)
- Michael Staab
- Ecological Networks, Technical University Darmstadt, Darmstadt, Germany
- Nature Conservation and Landscape Ecology, University of Freiburg, Freiburg im Breisgau, Germany
| | - Stefanie Pietsch
- Nature Conservation and Landscape Ecology, University of Freiburg, Freiburg im Breisgau, Germany
- Field Station Fabrikschleichach, University of Würzburg, Würzburg, Germany
| | - Haoru Yan
- State Key Laboratory of Vegetation and Environmental Change, Institute of Botany, Chinese Academy of Sciences, Beijing, China
- College of Life Sciences, University of Chinese Academy of Sciences, Beijing, China
| | - Nico Blüthgen
- Ecological Networks, Technical University Darmstadt, Darmstadt, Germany
| | - Anpeng Cheng
- State Key Laboratory of Vegetation and Environmental Change, Institute of Botany, Chinese Academy of Sciences, Beijing, China
- College of Life Sciences, University of Chinese Academy of Sciences, Beijing, China
| | - Yi Li
- State Key Laboratory of Vegetation and Environmental Change, Institute of Botany, Chinese Academy of Sciences, Beijing, China
| | - Naili Zhang
- College of Forestry, Beijing Forestry University, Beijing, China
| | - Keping Ma
- State Key Laboratory of Vegetation and Environmental Change, Institute of Botany, Chinese Academy of Sciences, Beijing, China
- College of Life Sciences, University of Chinese Academy of Sciences, Beijing, China
| | - Xiaojuan Liu
- State Key Laboratory of Vegetation and Environmental Change, Institute of Botany, Chinese Academy of Sciences, Beijing, China
- Zhejiang Qianjiangyuan Forest Biodiversity National Observation and Research Station, Beijing, China
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Jensen IC, Hansen RR, Damgaard C, Offenberg J. Implementing wood ants in biocontrol: Suppression of apple scab and reduced aphid tending. PEST MANAGEMENT SCIENCE 2023; 79:2415-2422. [PMID: 36811225 DOI: 10.1002/ps.7422] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/17/2022] [Revised: 02/10/2023] [Accepted: 02/21/2023] [Indexed: 06/02/2023]
Abstract
BACKGROUND Ants can become efficient biocontrol agents in plantation crops as they prey on pest insects and may inhibit plant pathogens by excreting broad-spectrum antibiotics. However, ants also provide a disservice by augmenting attended honeydew producing homopterans. This disservice may be avoided by offering ants artificial sugar as an alternative to honeydew. Here we tested the effect of artificial sugar feeding on aphid abundance in an apple plot with wood ants (Formica polyctena, Förster), and tested the effect of ant presence on apple scab (Venturia inaequalis, Cooke) disease incidence. RESULTS Over a 2-year period, sugar feeding eliminated ant-attended aphid populations on the apple trees. Furthermore, scab symptoms on both leaves and apples were reduced considerably on ant trees compared to control trees without ants. The presence of ants on the trees reduced leaf scab infections by 34%, whereas spot numbers on fruits were reduced by between 53 and 81%, depending on apple variety. In addition, the spots were 56% smaller. CONCLUSION This shows that problems with wood ant-attended homopterans can be solved and that ants can control both insect pests and plant pathogens. We therefore propose wood ants as a new effective biocontrol agent suitable for implementation in apple orchards and possibly other plantation crops. © 2023 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.
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Rambau U, Naidoo Y, Sadashiva CT, Baijnath H, Dewir YH, Magyar-Tábori K. The Foliar Anatomy and Micromorphology of Cyphostemma hypoleucum (Vitaceae). PLANTS (BASEL, SWITZERLAND) 2023; 12:2312. [PMID: 37375937 DOI: 10.3390/plants12122312] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/04/2023] [Revised: 06/08/2023] [Accepted: 06/09/2023] [Indexed: 06/29/2023]
Abstract
Cyphostemma hypoleucum (Harv.) Desc. ex Wild & R.B. Drumm is a perennial climber, indigenous to Southern Africa, and belongs to the Vitaceae. Although there have been many studies of Vitaceae micromorphology, only a few taxa have been described in detail. This study aimed to characterize the micro-morphology of the leaf indumentum and determining its possible functions. Stereo microscope, scanning electron microscope (SEM), and transmission electron microscope (TEM) were used to produce images. Micrographs of stereomicroscopy and SEM showed the presence of non-glandular trichomes. In addition, pearl glands were observed on the abaxial surface using a stereo microscope and SEM. These were characterized by a short stalk and a spherical- shaped head. The density of trichomes decreased on both surfaces of leaves as the leaf expanded. Idioblasts that contained raphide crystals were also detected in tissues. The results obtained from various microscopy techniques confirmed that non-glandular trichomes serve as the main external appendages of the leaves. Additionally, their functions may include serving as a mechanical barrier against environmental factors such as low humidity, intense light, elevated temperatures, as well as herbivory and insect oviposition. Our results may also be added to the existing body of knowledge with regard to microscopic research and taxonomic applications.
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Affiliation(s)
- Unarine Rambau
- School of Life Sciences, University of KwaZulu-Natal, Westville Campus, Private Bag X54001, Durban 4000, South Africa
| | - Yougasphree Naidoo
- School of Life Sciences, University of KwaZulu-Natal, Westville Campus, Private Bag X54001, Durban 4000, South Africa
| | | | - Himansu Baijnath
- School of Life Sciences, University of KwaZulu-Natal, Westville Campus, Private Bag X54001, Durban 4000, South Africa
| | - Yaser Hassan Dewir
- Plant Production Department, College of Food and Agriculture Sciences, King Saud University, Riyadh 11451, Saudi Arabia
| | - Katalin Magyar-Tábori
- Research Institute of Nyíregyháza, Institutes for Agricultural Research and Educational Farm (IAREF), University of Debrecen, P.O. Box 12, 4400 Nyíregyháza, Hungary
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Al-Khayri JM, Rashmi R, Toppo V, Chole PB, Banadka A, Sudheer WN, Nagella P, Shehata WF, Al-Mssallem MQ, Alessa FM, Almaghasla MI, Rezk AAS. Plant Secondary Metabolites: The Weapons for Biotic Stress Management. Metabolites 2023; 13:716. [PMID: 37367873 DOI: 10.3390/metabo13060716] [Citation(s) in RCA: 13] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2023] [Revised: 05/26/2023] [Accepted: 05/29/2023] [Indexed: 06/28/2023] Open
Abstract
The rise in global temperature also favors the multiplication of pests and pathogens, which calls into question global food security. Plants have developed special coping mechanisms since they are sessile and lack an immune system. These mechanisms use a variety of secondary metabolites as weapons to avoid obstacles, adapt to their changing environment, and survive in less-than-ideal circumstances. Plant secondary metabolites include phenolic compounds, alkaloids, glycosides, and terpenoids, which are stored in specialized structures such as latex, trichomes, resin ducts, etc. Secondary metabolites help the plants to be safe from biotic stressors, either by repelling them or attracting their enemies, or exerting toxic effects on them. Modern omics technologies enable the elucidation of the structural and functional properties of these metabolites along with their biosynthesis. A better understanding of the enzymatic regulations and molecular mechanisms aids in the exploitation of secondary metabolites in modern pest management approaches such as biopesticides and integrated pest management. The current review provides an overview of the major plant secondary metabolites that play significant roles in enhancing biotic stress tolerance. It examines their involvement in both indirect and direct defense mechanisms, as well as their storage within plant tissues. Additionally, this review explores the importance of metabolomics approaches in elucidating the significance of secondary metabolites in biotic stress tolerance. The application of metabolic engineering in breeding for biotic stress resistance is discussed, along with the exploitation of secondary metabolites for sustainable pest management.
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Affiliation(s)
- Jameel M Al-Khayri
- Department of Agricultural Biotechnology, College of Agriculture and Food Sciences, King Faisal University, Al-Ahsa 31982, Saudi Arabia
| | - Ramakrishnan Rashmi
- Department of Life Sciences, CHRIST (Deemed to be University), Bangalore 560 029, Karnataka, India
| | - Varsha Toppo
- Department of Life Sciences, CHRIST (Deemed to be University), Bangalore 560 029, Karnataka, India
| | - Pranjali Bajrang Chole
- Department of Life Sciences, CHRIST (Deemed to be University), Bangalore 560 029, Karnataka, India
| | - Akshatha Banadka
- Department of Life Sciences, CHRIST (Deemed to be University), Bangalore 560 029, Karnataka, India
| | - Wudali Narasimha Sudheer
- Department of Life Sciences, CHRIST (Deemed to be University), Bangalore 560 029, Karnataka, India
| | - Praveen Nagella
- Department of Life Sciences, CHRIST (Deemed to be University), Bangalore 560 029, Karnataka, India
| | - Wael Fathi Shehata
- Department of Agricultural Biotechnology, College of Agriculture and Food Sciences, King Faisal University, Al-Ahsa 31982, Saudi Arabia
| | - Muneera Qassim Al-Mssallem
- Department of Food Science and Nutrition, College of Agriculture and Food Sciences, King Faisal University, Al-Ahsa 31982, Saudi Arabia
| | - Fatima Mohammed Alessa
- Department of Food Science and Nutrition, College of Agriculture and Food Sciences, King Faisal University, Al-Ahsa 31982, Saudi Arabia
| | - Mustafa Ibrahim Almaghasla
- Department of Arid Land Agriculture, College of Agriculture and Food Sciences, King Faisal University, Al-Ahsa 31982, Saudi Arabia
- Plant Pests, and Diseases Unit, College of Agriculture and Food Sciences, King Faisal University, Al-Ahsa 31982, Saudi Arabia
| | - Adel Abdel-Sabour Rezk
- Department of Agricultural Biotechnology, College of Agriculture and Food Sciences, King Faisal University, Al-Ahsa 31982, Saudi Arabia
- Department of Virus and Phytoplasma, Plant Pathology Institute, Agricultural Research Center, Giza 12619, Egypt
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Cavallini L, Peterson RKD, Weaver DK. Cowpea extrafloral nectar has potential to provide ecosystem services lost in agricultural intensification and support native parasitoids that suppress the wheat stem sawfly. JOURNAL OF ECONOMIC ENTOMOLOGY 2023:7161738. [PMID: 37178180 DOI: 10.1093/jee/toad083] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/03/2023] [Revised: 04/12/2023] [Accepted: 04/24/2023] [Indexed: 05/15/2023]
Abstract
The native parasitoids Bracon cephi (Gahan) and B. lissogaster Muesebeck (Hymenoptera: Braconidae) reduce populations of Cephus cinctus Norton (Hymenoptera: Cephidae), a native grassland species, and major wheat pest on the Northern Great Plains of North America. Non-host feeding adults of these braconids increase longevity, egg load, and egg volume when provisioned carbohydrate-rich diets. Nutrition from nectar can enhance the success of natural enemies in pest management programs. Cowpea, Vigna unguiculata (L.) Walpers, is a potential cover-crop that could add resilient features to the landscape and has extrafloral nectaries (EFN), easy-access nectar sources for beneficial insects. If more cowpea was grown on the Northern Great Plains, would B. cephi and B. lissogaster benefit from foraging on putatively beneficial EFN? We investigated cowpea inflorescence stalk extrafloral nectars (IS-EFN) and leaf stipel extrafloral nectars (LS-EFN) as potential food sources for these parasitoids. Females were caged on EFN sources on living cowpea plants to assess longevity. Egg load and volume were measured at 2, 5, and 10 days after placement. Bracon cephi survived 10 days on water, 38 days on IS-EFN; B. lissogaster 6 days on water, 28 days on IS-EFN. Bracon lissogaster maintained a constant egg load and volume across treatments while B. cephi produced 2.1-fold more eggs that were 1.6-fold larger on IS-EFN. Y-tube olfactometry indicated adult females were attracted to airstreams containing cowpea volatiles. These results demonstrate that non-native, warm-season cowpea benefits these native parasitoids and may improve conservation biocontrol of C. cinctus.
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Affiliation(s)
- Laissa Cavallini
- Department of Entomology and Plant Pathology, North Carolina State University, Raleigh, NC, USA
| | - Robert K D Peterson
- Department of Land Resources and Environmental Sciences, Montana State University, Bozeman, MT, USA
| | - David K Weaver
- Department of Land Resources and Environmental Sciences, Montana State University, Bozeman, MT, USA
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Straser RK, Reger JE, Wilson H. Diet quality influences nutrient retention and reproductive fitness of the biocontrol agent Hadronotus pennsylvanicus (Hymenoptera: Scelionidae). JOURNAL OF INSECT PHYSIOLOGY 2023; 147:104522. [PMID: 37169272 DOI: 10.1016/j.jinsphys.2023.104522] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/23/2023] [Revised: 04/17/2023] [Accepted: 05/06/2023] [Indexed: 05/13/2023]
Abstract
Diet can have a direct influence on the reproductive success of parasitoid wasps. For synovigenic parasitoids, the nutrients obtained from floral resources, such as nectar and pollen, play a vital role in fueling bodily functions and physiological energy expenditure incurred from reproduction. Insufficient access to nutrient-rich diets can lead to lower rates of reproductive fitness, therefore reducing the efficacy of biocontrol. Here, a study was conducted to evaluate the influence of diet quality on nutrient retention and reproductive fitness of the egg parasitoid Hadronotus pennsylvanicus (Hymenoptera: Scelionidae), a prospective biocontrol agent for the leaffooted bug Leptoglossus zonatus (Heteroptera: Coreidae), a primary pest of almonds and pistachios. Newly emerged parasitoid females were provided host eggs every other day accompanied by diets of varying sucrose concentrations (source of carbohydrates) and pollen (source of lipid and proteins). The sucrose concentration in the diet, regardless of pollen content, significantly increased the survival and lifetime fecundity of female H. pennsylvanicus. While wasps fed high sucrose diets depleted bodily sugars, glycogen, and lipids at a slower rate than wasps fed low sucrose diets, there was no effect on bodily protein levels. Given these findings, further research is now needed to identify floral resources that are compatible, attractive, and nutritionally-sufficient for optimal H. pennsylvanicus reproductive fitness, which could lead to enhanced parasitism of L. zonatus in crop systems.
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Affiliation(s)
- Robert K Straser
- Department of Entomology, University of California, Riverside, Riverside, CA, 92521, USA.
| | - Joshua E Reger
- Department of Entomology, University of California, Riverside, Riverside, CA, 92521, USA
| | - Houston Wilson
- Department of Entomology, University of California, Riverside, Riverside, CA, 92521, USA
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Lambert P, Confolent C, Heurtevin L, Dlalah N, Signoret V, Quilot-Turion B, Pascal T. Insertion of a mMoshan transposable element in PpLMI1, is associated with the absence or globose phenotype of extrafloral nectaries in peach [Prunus persica (L.) Batsch]. HORTICULTURE RESEARCH 2022; 9:uhab044. [PMID: 35039854 PMCID: PMC8829895 DOI: 10.1093/hr/uhab044] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/18/2020] [Revised: 08/14/2021] [Accepted: 09/17/2021] [Indexed: 06/14/2023]
Abstract
Most commercial peach [Prunus persica (L.) Batsch] cultivars have leaves with extrafloral nectaries (EFNs). Breeders have selected this character over time, as they observed that the eglandular phenotype resulted in high susceptibility to peach powdery mildew, a major disease of peach trees. EFNs are controlled by a Mendelian locus (E), mapped on chromosome 7. However, the genetic factor underlying E was unknown. In order to address this point, we developed a mapping population of 833 individuals derived from the selfing of "Malo Konare", a Bulgarian peach cultivar, heterozygous for the trait. This progeny was used to investigate the E-locus region, along with additional resources including peach genomic resequencing data, and 271 individuals from various origins used for validation. High-resolution mapping delimited a 40.6 kbp interval including the E-locus and four genes. Moreover, three double-recombinants allowed identifying Prupe.7G121100, a LMI1-like homeodomain leucine zipper (HD-Zip) transcription factor, as a likely candidate for the trait. By comparing peach genomic resequencing data from individuals with contrasted phenotypes, a MITE-like transposable element of the hAT superfamily (mMoshan) was identified in the third exon of Prupe.7G121100. It was associated with the absence or globose phenotype of EFNs. The insertion of the transposon was positively correlated with enhanced expression of Prupe.7G121100. Furthermore, a PCR marker designed from the sequence-variants, allowed to properly assign the phenotypes of all the individuals studied. These findings provide valuable information on the genetic control of a trait poorly known so far although selected for a long time in peach.
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Affiliation(s)
| | - Carole Confolent
- INRAE, GAFL, Montfavet, F-84143, FRANCE
- INRAE, UMR GDEC, Clermont-Ferrand, F-63100, FRANCE
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Singh A, Mayer VE, Zytynska SE, Hesse B, Weisser WW. The Efficiency of Plant Defense: Aphid Pest Pressure Does Not Alter Production of Food Rewards by Okra Plants in Ant Presence. FRONTIERS IN PLANT SCIENCE 2021; 12:627570. [PMID: 33790922 PMCID: PMC8005652 DOI: 10.3389/fpls.2021.627570] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/09/2020] [Accepted: 02/19/2021] [Indexed: 06/12/2023]
Abstract
Pearl bodies are produced by some plant species as food reward for ants and in exchange, ants defend these plants against insect pests. Sap-sucking pests such as aphids also excrete honeydew as food reward for ants, leading to potential conflict where ants could preferentially defend either the plant or the aphid. How pest insects might influence plant pearl body production, is yet to be investigated. Okra is a widely consumed vegetable worldwide and is attacked by the ant-tended cotton aphid. The plants produce pearl bodies, which are predominantly found on the underside of the leaves and formed from epidermal cells. We conducted a set of field and greenhouse experiments to explore plant-aphid-ant interactions, their influence on pearl body production and resulting performance of okra plants, across okra varieties. We found that ants of Pheidole genus, which are dominant in okra fields, preferred pearl bodies over aphid honeydew; although, their highest abundance was recorded in presence of both these food rewards, and on one okra variety. Removal of pearl bodies from the plants increased their production; however, plant growth and chlorophyll content were negatively associated with pearl body replenishment. Potentially to mitigate this resource cost, plants developed such a novel defense response because we found that aphid presence reduced pearl body production, but only when there were no ants. Finally, aphids negatively affected plant performance, but only at very high densities. As aphids also attract ants, plants may tolerate their presence at low densities to attract higher ant abundances. Our study highlights that plants can adapt their defense strategies in pest presence for efficient resource use. We suggest that understanding pearl body associated interactions in crop plants can assist in using such traits for pest management.
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Affiliation(s)
- Akanksha Singh
- Chair for Terrestrial Ecology, Department of Ecology and Ecosystem Management, Technische Universität München, Freising, Germany
- Agricultural Ecology Group, Department of Environmental Systems Science, ETH Zurich, Zurich, Switzerland
| | - Veronika E. Mayer
- Department of Botany and Biodiversity Research, Division of Structural and Functional Botany, University of Vienna, Wien, Austria
| | - Sharon E. Zytynska
- Chair for Terrestrial Ecology, Department of Ecology and Ecosystem Management, Technische Universität München, Freising, Germany
- Department of Evolution, Ecology and Behavior, Institute of Infection, Veterinary and Ecological Sciences, University of Liverpool, Liverpool, United Kingdom
| | - Benjamin Hesse
- Land Surface-Atmosphere Interactions, AG Ecophysiology of Plants, Department for Ecology and Ecosystem Management, School of Life Sciences Weihenstephan, Technische Universität München, Freising, Germany
| | - Wolfgang W. Weisser
- Chair for Terrestrial Ecology, Department of Ecology and Ecosystem Management, Technische Universität München, Freising, Germany
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Schifani E, Castracani C, Giannetti D, Spotti FA, Reggiani R, Leonardi S, Mori A, Grasso DA. New Tools for Conservation Biological Control: Testing Ant-Attracting Artificial Nectaries to Employ Ants as Plant Defenders. INSECTS 2020; 11:insects11020129. [PMID: 32079350 PMCID: PMC7074267 DOI: 10.3390/insects11020129] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/08/2019] [Revised: 02/11/2020] [Accepted: 02/13/2020] [Indexed: 01/29/2023]
Abstract
Knowledge of the role of ants in many agroecosystems is relatively scarce, and in temperate regions the possibility to exploit ants as biocontrol agents for crop protection is still largely unexplored. Drawing inspiration from mutualistic ant–plant relationships mediated by extrafloral nectaries (EFNs), we tested the use of artificial nectaries (ANs) in order to increase ant activity on pear trees and to evaluate the effects on the arthropods, plant health and fruit production. While EFNs secrete a complex solution mainly composed of sugars and amino acids, ANs were filled with water and sucrose only. The results suggest that ANs can be used as manipulative instruments to increase ant activity over long periods of time. High ant activity was significantly linked to lower incidence of the pathogen fungus Venturia pyrina (pear scab) on pear leaves, and of the presence of Cydia pomonella (codling moth) caterpillars on pear fruit production. These results further encourage exploring underrated possibilities in the development of new tools for conservation biological control (CBC).
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Affiliation(s)
- Enrico Schifani
- Department of Chemistry, Life Sciences & Environmental Sustainability, University of Parma, Parco Area delle Scienze, 11/a, 43124 Parma, Italy; (D.G.); (F.A.S.); (S.L.); (A.M.); (D.A.G.)
- Correspondence: (E.S.); (C.C.)
| | - Cristina Castracani
- Department of Chemistry, Life Sciences & Environmental Sustainability, University of Parma, Parco Area delle Scienze, 11/a, 43124 Parma, Italy; (D.G.); (F.A.S.); (S.L.); (A.M.); (D.A.G.)
- Correspondence: (E.S.); (C.C.)
| | - Daniele Giannetti
- Department of Chemistry, Life Sciences & Environmental Sustainability, University of Parma, Parco Area delle Scienze, 11/a, 43124 Parma, Italy; (D.G.); (F.A.S.); (S.L.); (A.M.); (D.A.G.)
| | - Fiorenza Augusta Spotti
- Department of Chemistry, Life Sciences & Environmental Sustainability, University of Parma, Parco Area delle Scienze, 11/a, 43124 Parma, Italy; (D.G.); (F.A.S.); (S.L.); (A.M.); (D.A.G.)
| | - Roberto Reggiani
- Azienda Agraria Sperimentale Stuard, Strada Madonna dell’Aiuto, 7/a, 43126 San Pancrazio, Parma, Italy;
| | - Stefano Leonardi
- Department of Chemistry, Life Sciences & Environmental Sustainability, University of Parma, Parco Area delle Scienze, 11/a, 43124 Parma, Italy; (D.G.); (F.A.S.); (S.L.); (A.M.); (D.A.G.)
| | - Alessandra Mori
- Department of Chemistry, Life Sciences & Environmental Sustainability, University of Parma, Parco Area delle Scienze, 11/a, 43124 Parma, Italy; (D.G.); (F.A.S.); (S.L.); (A.M.); (D.A.G.)
| | - Donato Antonio Grasso
- Department of Chemistry, Life Sciences & Environmental Sustainability, University of Parma, Parco Area delle Scienze, 11/a, 43124 Parma, Italy; (D.G.); (F.A.S.); (S.L.); (A.M.); (D.A.G.)
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Jones AG, Hoover K, Pearsons K, Tooker JF, Felton GW. Potential Impacts of Translocation of Neonicotinoid Insecticides to Cotton (Gossypium hirsutum (Malvales: Malvaceae)) Extrafloral Nectar on Parasitoids. ENVIRONMENTAL ENTOMOLOGY 2020; 49:159-168. [PMID: 31880775 DOI: 10.1093/ee/nvz157] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/12/2019] [Indexed: 06/10/2023]
Abstract
Neonicotinoid seed treatments are frequently used in cotton (Gossypium hirsutum L. [Malvales: Malvaceae]) production to provide protection against early-season herbivory. However, there is little known about how these applications affect extrafloral nectar (EFN), an important food resource for arthropod natural enemies. Using enzyme-linked immunosorbent assays, we found that neonicotinoids were translocated to the EFN of clothianidin- and imidacloprid-treated, greenhouse-grown cotton plants at concentrations of 77.3 ± 17.3 and 122.6 ± 11.5 ppb, respectively. We did not find differences in the quantity of EFN produced by neonicotinoid-treated cotton plants compared to untreated controls, either constitutively or after mechanical damage. Metabolomic analysis of sugars and amino acids from treated and untreated plants did not detect differences in overall composition of EFN. In bioassays, female Cotesia marginiventris (Cresson) (Hymenoptera: Braconidae) parasitoid wasps that fed on EFN from untreated, clothianidin-treated, or imidacloprid-treated plants demonstrated no difference in mortality or parasitization success. We also conducted acute toxicity assays for C. marginiventris fed on honey spiked with clothianidin and imidacloprid and established LC50 values for male and female wasps. Although LC50 values were substantially higher than neonicotinoid concentrations detected in EFN, caution should be used when translating these results to the field where other stressors could alter the effects of neonicotinoids. Moreover, there are a wide range of possible sublethal impacts of neonicotinoids, none of which were explored here. Our results suggest that EFN is a potential route of exposure of neonicotinoids to beneficial insects and that further field-based studies are warranted.
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Affiliation(s)
- Asher G Jones
- Department of Entomology, The Pennsylvania State University, University Park, PA
| | - Kelli Hoover
- Department of Entomology, The Pennsylvania State University, University Park, PA
| | - Kirsten Pearsons
- Department of Entomology, The Pennsylvania State University, University Park, PA
| | - John F Tooker
- Department of Entomology, The Pennsylvania State University, University Park, PA
| | - Gary W Felton
- Department of Entomology, The Pennsylvania State University, University Park, PA
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Saldanha AV, Gontijo LM, Carvalho RM, Vasconcelos CJ, Corrêa AS, Gandra RL. Companion planting enhances pest suppression despite reducing parasitoid emergence. Basic Appl Ecol 2019. [DOI: 10.1016/j.baae.2019.10.002] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Herz A, Cahenzli F, Penvern S, Pfiffner L, Tasin M, Sigsgaard L. Managing Floral Resources in Apple Orchards for Pest Control: Ideas, Experiences and Future Directions. INSECTS 2019; 10:insects10080247. [PMID: 31405257 PMCID: PMC6723448 DOI: 10.3390/insects10080247] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/31/2019] [Revised: 08/02/2019] [Accepted: 08/06/2019] [Indexed: 11/16/2022]
Abstract
Functional biodiversity is of fundamental importance for pest control. Many natural enemies rely on floral resources to complete their life cycle. Farmers need to ensure the availability of suitable and sufficient floral biodiversity. This review summarizes 66 studies on the management of floral biodiversity in apple orchards, published since 1986. Approaches followed different degrees of intervention: short-term practices (mowing regime and weed maintenance, cover crops), establishment of durable ecological infrastructures (perennial flower strips, hedgerows) and re-design of the crop system (intercropping, agroforestry). Although short-term practices did not always target the nutrition of natural enemies by flowering plants, living conditions for them (alternative prey, provision of habitat) were often improved. Perennial flower strips reliably enhanced natural enemies and techniques for their introduction continuously developed. Resident natural enemies and their impact in pest control reacted positively to the introduction of a more diversified vegetation, whereas the response of very mobile organisms was often not directly linked to the measures taken. A careful selection and management of plants with particular traits exploitable by most natural enemies emerged as a key-point for success. Now the elaborated design of such measures needs to be adopted by stakeholders and policy makers to encourage farmers to implement these measures in their orchards.
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Affiliation(s)
- Annette Herz
- Julius Kühn-Institut, Institute for Biological Control, Heinrichstr. 243, 64287 Darmstadt, Germany.
| | - Fabian Cahenzli
- Department of Crop Sciences, Research Institute of Organic Agriculture (FiBL), Ackerstrasse 113, 5070 Frick, Switzerland
| | - Servane Penvern
- INRA, Centre de Recherche PACA, UR Ecodeveloppement, 84914 Avignon, France
| | - Lukas Pfiffner
- Department of Crop Sciences, Research Institute of Organic Agriculture (FiBL), Ackerstrasse 113, 5070 Frick, Switzerland
| | - Marco Tasin
- Department of Plant Protection Biology-Unit of Integrated Plant Protection, Swedish University of Agricultural Science, P.O. Box 102, SE-230 53 Alnarp, Sweden
| | - Lene Sigsgaard
- Department of Plant and Environmental Sciences, University of Copenhagen (UCPH), Thorvaldsensvej 40, DK-1871 Frederiksberg C, Denmark
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Hernández-Zepeda OF, Razo-Belman R, Heil M. Reduced Responsiveness to Volatile Signals Creates a Modular Reward Provisioning in an Obligate Food-for-Protection Mutualism. FRONTIERS IN PLANT SCIENCE 2018; 9:1076. [PMID: 30087690 PMCID: PMC6066664 DOI: 10.3389/fpls.2018.01076] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/30/2018] [Accepted: 07/03/2018] [Indexed: 05/07/2023]
Abstract
Plants in more than 100 families secrete extrafloral nectar (EFN) to establish food-for-protection mutualisms with ants. Facultative ant-plants secrete EFN as a jasmonic acid (JA)-dependent response to attract generalist ants. In contrast, obligate ant-plants like the Central American "Swollen-Thorn Acacias" are colonized by specialized ants, although an individual host can carry ant colonies from different species that differ in the degree of protection they provide. We hypothesized that hosts that associate simultaneously with various partners should produce rewards in a modular manner to preferentially reward high quality partners. To test this hypothesis, we applied JA to distinct leaves and quantified cell wall invertase activity (CWIN; a regulator of nectar secretion) and EFN secretion by these "local" (i.e., treated) and the "systemic" (i.e., non-treated) leaves of the same branch. Both CWIN activity and EFN secretion increased in local and systemic leaves of the facultative ant-plant Acacia cochliacantha, but only in the local leaves of the obligate ant-plant, A. cornigera. The systemic EFN secretion in A. cochliacantha was associated with an enhanced emission of volatile organic compounds (VOCs). Such VOCs function as "external signals" that control systemic defense responses in diverse plant species. Indeed, the headspace of JA-treated branches of A. cochliacantha induced EFN secretion in both plant species, whereas the headspace of A. cornigera caused no detectable induction effect. Analyses of the headspace using GC-MS identified six VOCs in the headspace of A. cochliacantha that were not emitted by A. cornigera. Among these VOCs, β-caryophyllene and (cis)-hexenyl isovalerate have already been reported in other plant species to induce defense traits, including EFN secretion. Our observations underline the importance of VOCs as systemic within-plant signals and show that the modular rewarding in A. cornigera is likely to result from a reduced emission of the systemic signal, rather than from a reduced responsiveness to the signal. We suggest that modular rewarding allows hosts to restrict the metabolic investment to specific partners and to efficiently sanction potential exploiters.
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