1
|
Bruno P, Arce CCM, Machado RAR, Besomi G, Spescha A, Glauser G, Jaccard C, Benrey B, Turlings TCJ. Sequestration of cucurbitacins from cucumber plants by Diabrotica balteata larvae provides little protection against biological control agents. JOURNAL OF PEST SCIENCE 2022; 96:1061-1075. [PMID: 37181825 PMCID: PMC10169900 DOI: 10.1007/s10340-022-01568-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/23/2022] [Revised: 09/15/2022] [Accepted: 09/21/2022] [Indexed: 05/16/2023]
Abstract
Cucurbitaceae plants produce cucurbitacins, bitter triterpenoids, to protect themselves against various insects and pathogens. Adult banded cucumber beetles (Diabrotica balteata), a common pest of maize and cucurbits, sequester cucurbitacins, presumably as a defensive mechanism against their natural enemies, which might reduce the efficacy of biological control agents. Whether the larvae also sequester and are protected by cucurbitacins is unclear. We profiled cucurbitacin levels in four varieties of cucumber, Cucumis sativus, and in larvae fed on these varieties. Then, we evaluated larval growth and resistance against common biocontrol organisms including insect predators, entomopathogenic nematodes, fungi and bacteria. We found considerable qualitative and quantitative differences in the cucurbitacin levels of the four cucumber varieties. While two varieties were fully impaired in their production, the other two accumulated high levels of cucurbitacins. We also observed that D. balteata larvae sequester and metabolize cucurbitacins, and although the larvae fed extensively on both belowground and aboveground tissues, the sequestered cucurbitacins were mainly derived from belowground tissues. Cucurbitacins had no detrimental effects on larval performance and, surprisingly, did not provide protection against any of the natural enemies evaluated. Our results show that D. balteata larvae can indeed sequester and transform cucurbitacins, but sequestered cucurbitacins do not impact the biocontrol potential of common natural enemies used in biocontrol. Hence, this plant trait should be conserved in plant breeding programs, as it has been demonstrated in previous studies that it can provide protection against plant pathogens and generalist insects. Supplementary Information The online version contains supplementary material available at 10.1007/s10340-022-01568-3.
Collapse
Affiliation(s)
- Pamela Bruno
- Laboratory of Fundamental and Applied Research in Chemical Ecology, Institute of Biology, University of Neuchâtel, Neuchâtel, Switzerland
| | - Carla C. M. Arce
- Laboratory of Fundamental and Applied Research in Chemical Ecology, Institute of Biology, University of Neuchâtel, Neuchâtel, Switzerland
| | - Ricardo A. R. Machado
- Experimental Biology Group, Institute of Biology, University of Neuchâtel, Neuchâtel, Switzerland
| | - Gaia Besomi
- Laboratory of Fundamental and Applied Research in Chemical Ecology, Institute of Biology, University of Neuchâtel, Neuchâtel, Switzerland
| | - Anna Spescha
- Plant Pathology Group, Institute of Integrative Biology, ETH Zürich, Zürich, Switzerland
| | - Gaétan Glauser
- Neuchâtel Platform of Analytical Chemistry, University of Neuchâtel, Neuchâtel, Switzerland
| | - Charlyne Jaccard
- Laboratory of Evolutionary Entomology, Institute of Biology, University of Neuchâtel, Neuchâtel, Switzerland
| | - Betty Benrey
- Laboratory of Evolutionary Entomology, Institute of Biology, University of Neuchâtel, Neuchâtel, Switzerland
| | - Ted C. J. Turlings
- Laboratory of Fundamental and Applied Research in Chemical Ecology, Institute of Biology, University of Neuchâtel, Neuchâtel, Switzerland
| |
Collapse
|
2
|
Loulou A, M’saad Guerfali M, Muller A, Bhat AH, Abolafia J, Machado RAR, Kallel S. Potential of Oscheius tipulae nematodes as biological control agents against Ceratitis capitata. PLoS One 2022; 17:e0269106. [PMID: 35671263 PMCID: PMC9200223 DOI: 10.1371/journal.pone.0269106] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2021] [Accepted: 05/13/2022] [Indexed: 11/18/2022] Open
Abstract
A survey to collect soil nematodes with potential to control Ceratitis
capitata flies was carried out in different locations in Tunisia.
Several nematode isolates were recovered, laboratory colonies were established,
and their taxonomic identities were determined based on molecular methods. Among
all the recovered nematode isolates, two of them, Oscheius
tipulae TC2 and OC2, were evaluated for their capacity to control
C. capitata flies and for their ability to
kill and reproduce on Galleria mellonella larvae. Our results
show a great potential of these two isolates as biocontrol agents as they kill
C. capitata eggs and pupae and interfere
with the metamorphosis of C. capitata larvae.
More specifically, TC2 and OC2 nematodes killed 39 and 31% of
C. capitata eggs, respectively, impaired the
metamorphosis of up to 77% and up to 67% of C.
capitata larvae, respectively, and killed up to 66% and up
to 58% of C. capitata pupae, respectively. The
efficacy of TC2 and OC2 nematodes was particularly high on C.
capitata pupae, and significant insect mortalities were
observed even at concentrations of 1 and 5 nematodes/pupae, respectively. We
also found that TC2 and OC2 nematodes efficiently kill and reproduce in
G. mellonella larvae, suggesting that
these insects could be used for mass-multiplication of these nematodes. These
results reveal the potential of O. tipulae to
complement integrated pest management programs against C.
capitata flies.
Collapse
Affiliation(s)
- Ameni Loulou
- Laboratory of Bio-aggressor and Integrated Protection in Agriculture,
Department of Plant health and Environment, National Agronomic Institute of
Tunisia, University of Carthage, Tunis, Tunisia
| | - Meriem M’saad Guerfali
- Laboratory of Biotechnology and Nuclear Technologies, National Center of
Nuclear Sciences and Technologies, Technopole Sidi Thabet, Ariana,
Tunisia
| | - Arthur Muller
- Faculty of Sciences, Experimental Biology Research Group, Institute of
Biology, University of Neuchâtel, Neuchâtel, Switzerland
| | - Aashaq Hussain Bhat
- Faculty of Sciences, Experimental Biology Research Group, Institute of
Biology, University of Neuchâtel, Neuchâtel, Switzerland
- Department of Zoology, Government Degree College, Kathua, Jammu, Jammu
and Kashmir, India
| | - Joaquín Abolafia
- Departamento de Biología Animal, Biología Vegetal y Ecología, Universidad
de Jaén, Jaén, Spain
| | - Ricardo A. R. Machado
- Faculty of Sciences, Experimental Biology Research Group, Institute of
Biology, University of Neuchâtel, Neuchâtel, Switzerland
- * E-mail: (RARM); (SK)
| | - Sadreddine Kallel
- Laboratory of Bio-aggressor and Integrated Protection in Agriculture,
Department of Plant health and Environment, National Agronomic Institute of
Tunisia, University of Carthage, Tunis, Tunisia
- * E-mail: (RARM); (SK)
| |
Collapse
|
3
|
Comparative Screening of Mexican, Rwandan and Commercial Entomopathogenic Nematodes to Be Used against Invasive Fall Armyworm, Spodoptera frugiperda. INSECTS 2022; 13:insects13020205. [PMID: 35206776 PMCID: PMC8878727 DOI: 10.3390/insects13020205] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/01/2021] [Revised: 02/07/2022] [Accepted: 02/11/2022] [Indexed: 11/17/2022]
Abstract
Simple Summary The fall armyworm is a devastating insect pest of maize that has recently spread from the Americas to Africa and Asia. Synthetic insecticides are currently being used excessively to fight this pest. Safe, effective and more sustainable alternatives are urgently needed. We explore the use of beneficial entomopathogenic nematodes to control the fall armyworm. These tiny soil-born roundworms are lethal parasites of insects, including caterpillars such as the fall armyworm. We tested forty nematode strains from either the native range of the fall armyworm (Mexico), or the area of invasion (Rwanda), and commercial strains. We found that certain strains of local nematodes from the area of invasion can be as effective in infecting and killing fall armyworm as commercial strains or those from the armyworm’s native range. These findings will aid the development of locally acceptable and effective biological control products. Abstract The fall armyworm (FAW), Spodoptera frugiperda Smith (Lepidoptera: Noctuidae) is an important pest of maize originating from the Americas. It recently invaded Africa and Asia, where it causes severe yield losses to maize. To fight this pest, tremendous quantities of synthetic insecticides are being used. As a safe and sustainable alternative, we explore the possibility to control FAW with entomopathogenic nematodes (EPN). We tested in the laboratory whether local EPNs, isolated in the invasive range of FAW, are as effective as EPNs from FAW native range or as commercially available EPNs. This work compared the virulence, killing speed and propagation capability of low doses of forty EPN strains, representing twelve species, after placing them with second-, third- and sixth-instar caterpillars as well as pupae. EPN isolated in the invasive range of FAW (Rwanda) were found to be as effective as commercial and EPNs from the native range of FAW (Mexico) at killing FAW caterpillars. In particular, the Rwandan Steinernema carpocapsae strain RW14-G-R3a-2 caused rapid 100% mortality of second- and third-instar and close to 75% of sixth-instar FAW caterpillars. EPN strains and concentrations used in this study were not effective in killing FAW pupae. Virulence varied greatly among EPN strains, underlining the importance of thorough EPN screenings. These findings will facilitate the development of local EPN-based biological control products for sustainable and environmentally friendly control of FAW in East Africa and beyond.
Collapse
|
4
|
Improving Natural Enemy Selection in Biological Control through Greater Attention to Chemical Ecology and Host-Associated Differentiation of Target Arthropod Pests. INSECTS 2022; 13:insects13020160. [PMID: 35206733 PMCID: PMC8877252 DOI: 10.3390/insects13020160] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/22/2021] [Revised: 01/28/2022] [Accepted: 01/31/2022] [Indexed: 12/04/2022]
Abstract
Host-associated differentiation (HAD) refers to cases in which genetically distinct populations of a species (e.g., herbivores or natural enemies) preferentially reproduce or feed on different host species. In agroecosystems, HAD often results in unique strains or biotypes of pest species, each attacking different species of crops. However, HAD is not restricted to pest populations, and may cascade to the third trophic level, affecting host selection by natural enemies, and ultimately leading to HAD within natural enemy species. Natural enemy HAD may affect the outcomes of biological control efforts, whether classical, conservation, or augmentative. Here, we explore the potential effects of pest and natural enemy HAD on biological control in agroecosystems, with emphases on current knowledge gaps and implications of HAD for selection of biological control agents. Additionally, given the importance of semiochemicals in mediating interactions between trophic levels, we emphasize the role of chemical ecology in interactions between pests and natural enemies, and suggest areas of consideration for biological control. Overall, we aim to jump-start a conversation concerning the relevance of HAD in biological control by reviewing currently available information on natural enemy HAD, identifying challenges to incorporating HAD considerations into biological control efforts, and proposing future research directions on natural enemy selection and HAD.
Collapse
|
5
|
Ecology and Evolutionary History of Diabrotica Beetles—Overview and Update. INSECTS 2022; 13:insects13020156. [PMID: 35206729 PMCID: PMC8877772 DOI: 10.3390/insects13020156] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/23/2021] [Revised: 01/28/2022] [Accepted: 01/29/2022] [Indexed: 12/10/2022]
Abstract
An overview is given on several aspects of evolutionary history, ecology, host plant use, and pharmacophagy of Diabrotica spp. with a focus on the evolution of host plant breadth and effects of plant compounds on natural enemies used for biocontrol of pest species in the group. Recent studies on each aspect are discussed, latest publications on taxonomic grouping of Diabrotica spp., and new findings on variations in the susceptibility of corn varieties to root feeding beetle larvae are presented. The further need for in-depth research on biology and ecology of the large number of non-pest species in the genus is pointed out.
Collapse
|
6
|
Beran F, Petschenka G. Sequestration of Plant Defense Compounds by Insects: From Mechanisms to Insect-Plant Coevolution. ANNUAL REVIEW OF ENTOMOLOGY 2022; 67:163-180. [PMID: 34995091 DOI: 10.1146/annurev-ento-062821-062319] [Citation(s) in RCA: 27] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Plant defense compounds play a key role in the evolution of insect-plant associations by selecting for behavioral, morphological, and physiological insect adaptations. Sequestration, the ability of herbivorous insects to accumulate plant defense compounds to gain a fitness advantage, represents a complex syndrome of adaptations that has evolved in all major lineages of herbivorous insects and involves various classes of plant defense compounds. In this article, we review progress in understanding how insects selectively accumulate plant defense metabolites and how the evolution of specific resistance mechanisms to these defense compounds enables sequestration. These mechanistic considerations are further integrated into the concept of insect-plant coevolution. Comparative genome and transcriptome analyses, combined with approaches based on analytical chemistry that are centered in phylogenetic frameworks, will help to reveal adaptations underlying the sequestration syndrome, which is essential to understanding the influence of sequestration on insect-plant coevolution.
Collapse
Affiliation(s)
- Franziska Beran
- Research Group Sequestration and Detoxification in Insects, Max Planck Institute for Chemical Ecology, Jena 07745, Germany;
| | - Georg Petschenka
- Department of Applied Entomology, University of Hohenheim, Stuttgart 70599, Germany;
| |
Collapse
|
7
|
Campos-Herrera R, Vicente-Díez I, Galeano M, Chelkha M, Del Mar González-Trujillo M, Puelles M, Labarga D, Pou A, Calvo J, Belda JE. Intraspecific virulence of entomopathogenic nematodes against the pests Frankliniella occidentalis (Thysanoptera: Thripidae) and Tuta absoluta (Lepidoptera: Gelechiidae). J Nematol 2021; 53:e2021-102. [PMID: 34957410 PMCID: PMC8672422 DOI: 10.21307/jofnem-2021-102] [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: 09/14/2021] [Indexed: 11/11/2022] Open
Abstract
Entomopathogenic nematodes (EPN) are excellent biocontrol agents against various insect pests. Novel biotechnological approaches can enhance their utility against insects above-ground, opening a new venue for selecting superior EPN against certain insects. We hypothesize that different populations of the same species but from different origins (habitat, ecoregion) will differ in their virulence. This study aimed to evaluate the virulence of various EPN populations against two pests of worldwide incidence and damage to high value crops: Frankliniella occidentalis (Thysanoptera: Thripidae) and Tuta absoluta (Lepidoptera: Gelechiidae). We tested 10 EPN populations belonging to three EPN species: Heterorhabditis bacteriophora (Koppert, MG-618b, AM-203, RM-102), Steinernema feltiae (Koppert, RS-5, AM-25, RM-107), and Steinernema carpocapsae (Koppert, MG-596a). Each EPN population was tested at two concentrations. Frankliniella occidentalis was tested at 160 and 80 IJs/cm2 and T. absoluta at 21 and 4 IJs/cm2. Control treatments followed the same experimental procedure but only adding distilled water. Overall, whenever different, higher IJs concentration resulted in lower adult emergence, higher larval mortality, and shorter time to kill the insects. Considering the low concentration, S. feltiae provided the best results for both insects and instars investigated, while H. bacteriophora and S. carpocapsae required a high concentration to reach similar or slightly better results. Differences among populations of each of the species were detected, but only the native populations of H. bacteriophora populations showed consistently higher control values against both insects/instar compared with the commercial one. Differences among S. feltiae and S. carpocapsae populations depended on the IJs concentration, insect, and instar. We consider S. feltiae a very promising species for their application against F. occidentalis and T. absoluta, with the Koppert population as the most consistent among the populations tested. Specific EPN-populations of S. carpocapsae and H. bacteriophora were good candidates against certain instar/insects at high concentrations. This study emphasized the importance of intraspecific variability for EPN virulence.
Collapse
Affiliation(s)
- Raquel Campos-Herrera
- Instituto de Ciencias de la Vid y del Vino (CSIC, Universidad de La Rioja, Gobierno de La Rioja) Finca La Grajera Ctra. Burgos Km. 6 Salida 13 Lo-20, Logroño 26007, Spain
| | - Ignacio Vicente-Díez
- Instituto de Ciencias de la Vid y del Vino (CSIC, Universidad de La Rioja, Gobierno de La Rioja) Finca La Grajera Ctra. Burgos Km. 6 Salida 13 Lo-20, Logroño 26007, Spain
| | - Magda Galeano
- R&D Department of Koppert España, S.L. Paraje Piedra Rodada, 470, Vícar, Almería 04738, Spain
| | - Maryam Chelkha
- Instituto de Ciencias de la Vid y del Vino (CSIC, Universidad de La Rioja, Gobierno de La Rioja) Finca La Grajera Ctra. Burgos Km. 6 Salida 13 Lo-20, Logroño 26007, Spain.,Research Team "Lombricidae, Improving Soil Productivity and Environment" (LAPSE), Ecole Normale Supérieure (E.N.S.), Centre Eau, Ressources Naturelles, Environnement et Développement Durable (CERNE2D), Mohammed V University, Avenue Mohamed Bel Hassan El Ouazzani, BP: 5118, Takaddoum - Rabat, Morocco
| | - María Del Mar González-Trujillo
- Instituto de Ciencias de la Vid y del Vino (CSIC, Universidad de La Rioja, Gobierno de La Rioja) Finca La Grajera Ctra. Burgos Km. 6 Salida 13 Lo-20, Logroño 26007, Spain
| | - Miguel Puelles
- Instituto de Ciencias de la Vid y del Vino (CSIC, Universidad de La Rioja, Gobierno de La Rioja) Finca La Grajera Ctra. Burgos Km. 6 Salida 13 Lo-20, Logroño 26007, Spain
| | - David Labarga
- Instituto de Ciencias de la Vid y del Vino (CSIC, Universidad de La Rioja, Gobierno de La Rioja) Finca La Grajera Ctra. Burgos Km. 6 Salida 13 Lo-20, Logroño 26007, Spain
| | - Alicia Pou
- Instituto de Ciencias de la Vid y del Vino (CSIC, Universidad de La Rioja, Gobierno de La Rioja) Finca La Grajera Ctra. Burgos Km. 6 Salida 13 Lo-20, Logroño 26007, Spain
| | - Javier Calvo
- R&D Department of Koppert España, S.L. Paraje Piedra Rodada, 470, Vícar, Almería 04738, Spain
| | - José Eduardo Belda
- R&D Department of Koppert España, S.L. Paraje Piedra Rodada, 470, Vícar, Almería 04738, Spain
| |
Collapse
|
8
|
Sun B, Zhang X, Song L, Zheng L, Wei X, Gu X, Cui Y, Hu B, Yoshiga T, Abd-Elgawad MM, Ruan W. Evaluation of indigenous entomopathogenic nematodes in Southwest China as potential biocontrol agents against Spodoptera litura (Lepidoptera: Noctuidae). J Nematol 2021; 53:e2021-83. [PMID: 34820628 PMCID: PMC8609611 DOI: 10.21307/jofnem-2021-083] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2021] [Indexed: 12/03/2022] Open
Abstract
Spodoptera litura is a notorious leaf feeding insect pest in the Asia-Pacific region and leads to a significant economic loss in vegetable and field crop production. Entomopathogenic nematodes (EPNs), lethal parasites of insects, are used as biocontrol agents. Yunnan Province in China is a well-known region due to its rich biodiversity. In the present study, a survey of EPNs using the Galleria-baiting technique was conducted in 2017 and 2018 throughout the entire Yunnan province. In total, 789 soil samples were collected from 232 sites, of which 75 samples were positive for EPNs. Phylogenetic analyses of ITS, D2D3 expansion region of the 28S rRNA gene, as well as mitochondrial cytochrome c oxidase subunit I (COI), were performed to identify isolated nematode species and evaluate their genetic diversity. In total, 13, 3, and 58 identified populations belong to Steinernema, Heterorhabditis, and Oscheius, respectively. The phylogenetic relationships of EPN species in the three genera were analyzed with the Neighbor-Joining method. The virulence of the trapped isolates in the genera of Steinernema, Heterorhabditis, and Oscheius against S. litura was evaluated. Ten new indigenous isolates from Steinernema and Heterorhabditis showed prominent virulence to S. litura within 48 hr which is equivalent to that of commercial EPNs populations. The present study provides background information on indigenous EPN resources for S. litura control in Asia-Pacific region.
Collapse
Affiliation(s)
- Bingjiao Sun
- College of Life Sciences, Nankai University, Tianjin, 30071, China
| | - Xiuqing Zhang
- College of Life Sciences, Nankai University, Tianjin, 30071, China
| | - Li Song
- Tianjin Recyclable Resources Institution, China Co-op, Tianjin, 300191, China
| | - Lixin Zheng
- College of Life Sciences, Nankai University, Tianjin, 30071, China
| | - Xianqin Wei
- College of Life Sciences, Nankai University, Tianjin, 30071, China
| | - Xinghui Gu
- Tobacco Company, Yuxi, 653100, Yunnan, China
| | - Yonghe Cui
- Tobacco Company, Yuxi, 653100, Yunnan, China
| | - Bin Hu
- Beijing Plant Protection Station, Beijing, 100029, China
| | - Toyoshi Yoshiga
- Faculty of Agriculture, Saga University, Saga, 8408502, Japan
| | - Mahfouz M Abd-Elgawad
- Plant Pathology Department, National Research Centre, ElBehoos St., Dokki, Giza, 12622, Egypt
| | - Weibin Ruan
- College of Life Sciences, Nankai University, Tianjin, 30071, China
| |
Collapse
|
9
|
Machado RA, Bhat AH, Abolafia J, Muller A, Bruno P, Fallet P, Arce CC, Turlings TC, Bernal JS, Kajuga J, Waweru B, Toepfer S. Multi-locus phylogenetic analyses uncover species boundaries and reveal the occurrence of two new entomopathogenic nematode species, Heterorhabditis ruandica n. sp. and Heterorhabditis zacatecana n. sp. J Nematol 2021; 53:e2021-89. [PMID: 34790901 PMCID: PMC8588743 DOI: 10.21307/jofnem-2021-089] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2021] [Indexed: 11/17/2022] Open
Abstract
Species of the nematode genus Heterorhabditis are important biological control agents against agricultural pests. The taxonomy of this group is still unclear as it currently relies on phylogenetic reconstructions based on a few genetic markers with little resolutive power, specially of closely related species. To fill this knowledge gap, we sequenced several phylogenetically relevant genetic loci and used them to reconstruct phylogenetic trees, to calculate sequence similarity scores, and to determine signatures of species- and population-specific genetic polymorphism. In addition, we revisited the current literature related to the description, synonymisation, and declaration as species inquirendae of Heterorhabditis species to compile taxonomically relevant morphological and morphometric characters, characterized new nematode isolates at the morphological and morphometrical level, and conducted self-crossing and cross-hybridization experiments. The results of this study show that the sequences of the mitochondrial cytochrome C oxidase subunit I (COI) gene provide better phylogenetic resolutive power than the sequences of nuclear rRNA genes and that this gene marker can phylogenetically resolve closely related species and even populations of the same species with high precision. Using this gene marker, we found two new species, Heterorhabditis ruandica n. sp. and Heterorhabditis zacatecana n. sp. A detailed characterization of these species at the morphological and morphometric levels and nematode reproduction assays revealed that the threshold for species delimitation in this genus, using COI sequences, is 97% to 98%. Our study illustrates the importance of rigorous morphological and morphometric characterization and multi-locus sequencing for the description of new species within the genus Heterorhabditis, serves to clarify the phylogenetic relationships of this important group of biological control agents, and can inform future species descriptions to advance our efforts towards developing more tools for sustainable and environmentally friendly agriculture.
Collapse
Affiliation(s)
- Ricardo A.R. Machado
- Experimental Biology Research Group. Institute of Biology. Faculty of Sciences. University of Neuchâtel. Rue Emile-Argand 11, 2000 Neuchâtel, Switzerland
| | - Aashaq Hussain Bhat
- Department of Zoology, Government Degree College. Billawar-184204, Kathua, Jammu, Jammu and Kashmir, India
| | - Joaquín Abolafia
- Departamento de Biología Animal, Biología Vegetal y Ecología, Universidad de Jaén, Campus ‘Las Lagunillas’ s/n, Edificio B3, 23071 Jaén, Spain
| | - Arthur Muller
- Experimental Biology Research Group. Institute of Biology. Faculty of Sciences. University of Neuchâtel. Rue Emile-Argand 11, 2000 Neuchâtel, Switzerland
| | - Pamela Bruno
- Laboratory of Fundamental and Applied Research in Chemical Ecology, Institute of Biology. Faculty of Sciences, University of Neuchâtel, 2000 Neuchâtel, Switzerland
| | - Patrick Fallet
- Laboratory of Fundamental and Applied Research in Chemical Ecology, Institute of Biology. Faculty of Sciences, University of Neuchâtel, 2000 Neuchâtel, Switzerland
| | - Carla C.M. Arce
- Laboratory of Fundamental and Applied Research in Chemical Ecology, Institute of Biology. Faculty of Sciences, University of Neuchâtel, 2000 Neuchâtel, Switzerland
| | - Ted C.J. Turlings
- Laboratory of Fundamental and Applied Research in Chemical Ecology, Institute of Biology. Faculty of Sciences, University of Neuchâtel, 2000 Neuchâtel, Switzerland
| | - Julio S. Bernal
- Department of Entomology, Texas A&M University, College Station, TX
| | - Joelle Kajuga
- Department of Crop Innovations & Technology Transfer. Rwanda Agriculture and Animal Resources Development Board, 5016 Kigali-Rwanda
| | - Bancy Waweru
- Department of Crop Innovations & Technology Transfer. Rwanda Agriculture and Animal Resources Development Board, 5016 Kigali-Rwanda
| | | |
Collapse
|
10
|
Ibrahim M, Loulou A, Brouk A, Muller A, Machado RAR, Kallel S. Parasites rather than phoronts: Teratorhabditis synpapillata nematodes reduce lifespan of their Rhynchophorus ferrugineus host in a life stage-dependent manner. Ecol Evol 2021; 11:12596-12604. [PMID: 34594523 PMCID: PMC8462169 DOI: 10.1002/ece3.8004] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2021] [Revised: 06/29/2021] [Accepted: 07/24/2021] [Indexed: 11/20/2022] Open
Abstract
Rhynchophorus ferrugineus Olivier (Coleoptera: Curculionidae) red palm weevils are often reported in association with different organisms including nematodes. The significance of this interaction and whether nematodes can influence their life-history traits is unclear. We collected Rhynchophorus ferrugineus red palm weevils at different developmental stages and locations in Tunisia, observed and dissected them in search for nematodes and other interacting organisms, established laboratory colonies and identified the nematodes associated with them, and conducted nematode-insect interaction assays to determine the capacity of the nematodes to influence their life-history traits. We observed Beauveria bassiana fungi in larvae, nymph, and adults; Centrouropoda and Uroobovella acari associated with the adults, and Teratorhabditis synpapillata nematodes associated with larvae and adults. Nematode-insect interaction bioassays revealed that T. synpapillata nematodes reduce the lifespan of the insect larvae in a population-dependent manner, but do not influence the lifespan of adults. Our study uncovers an important factor that may determine population dynamics of this important palm pests and provides evidence to conclude that these organisms establish a parasitic relationship, rather than a phoretic relationship.
Collapse
Affiliation(s)
- Manel Ibrahim
- Laboratoire de Recherche Bio‐agresseur et Protection Intégrée en Agriculture, LR14GR02Université de CarthageNational Agronomic Institute of TunisiaArianaTunisia
| | - Ameni Loulou
- Laboratoire de Recherche Bio‐agresseur et Protection Intégrée en Agriculture, LR14GR02Université de CarthageNational Agronomic Institute of TunisiaArianaTunisia
| | - Anissa Brouk
- Laboratoire de Recherche Bio‐agresseur et Protection Intégrée en Agriculture, LR14GR02Université de CarthageNational Agronomic Institute of TunisiaArianaTunisia
| | - Arthur Muller
- Experimental Biology Research GroupFaculty of SciencesInstitute of BiologyUniversity of Neuchâtel (UniNE)NeuchâtelSwitzerland
| | - Ricardo A. R. Machado
- Experimental Biology Research GroupFaculty of SciencesInstitute of BiologyUniversity of Neuchâtel (UniNE)NeuchâtelSwitzerland
| | - Sadreddine Kallel
- Laboratoire de Recherche Bio‐agresseur et Protection Intégrée en Agriculture, LR14GR02Université de CarthageNational Agronomic Institute of TunisiaArianaTunisia
| |
Collapse
|
11
|
Filgueiras CC, Willett DS. Non-lethal effects of entomopathogenic nematode infection. Sci Rep 2021; 11:17090. [PMID: 34429457 PMCID: PMC8384869 DOI: 10.1038/s41598-021-96270-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2021] [Accepted: 08/04/2021] [Indexed: 11/10/2022] Open
Abstract
Entomopathogenic nematodes are typically considered lethal parasites of insect hosts. Indeed they are employed as such for biological control of insect pests. The effects of exposure to entomopathogenic nematodes are not strictly limited to mortality, however. Here we explore non-lethal effects of exposure to entomopathogenic nematodes by introducing the relatively non-susceptible pupal stage of Delia antiqua to thirteen different strains. We specifically chose to inoculate the pupal stage because it tends to be more resistant to infection, yet resides in the soil where it could come into contact with EPN biological control agents. We find that there is no significant mortality at the pupal stage, but that there are a host of strain-dependent non-lethal effects during and after the transition to adulthood including altered developmental times and changes in risk of death compared to controls. We also find that exposure to specific strains can reduce risk of mortality. These results emphasize the strain-dependent nature of entomopathogenic nematode infection and highlight the positive and negative ramifications for non-lethal effects for biological control of insect pests. Our work emphasizes the need for strain-specific screening of biological control agents before wide-spread adoption.
Collapse
Affiliation(s)
- Camila C Filgueiras
- Natural Enemy Management and Applications (NEMA) Lab, Department of Biology, UNC Asheville, Asheville, USA.
| | - Denis S Willett
- Applied Chemical Ecology Technology (ACET) Lab, Cornell AgriTech, Cornell University, Ithaca, USA
| |
Collapse
|
12
|
Erb M, Züst T, Robert CAM. Using plant chemistry to improve interactions between plants, herbivores and their natural enemies: challenges and opportunities. Curr Opin Biotechnol 2021; 70:262-265. [PMID: 34242994 DOI: 10.1016/j.copbio.2021.05.011] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2021] [Accepted: 05/31/2021] [Indexed: 11/15/2022]
Abstract
Plant secondary (or specialized) metabolites determine multitrophic interaction dynamics. Herbivore natural enemies exploit plant volatiles for host location and are negatively affected by plant defense chemicals that are transferred through herbivores. Recent work shows that herbivore natural enemies can evolve resistance to plant defense chemicals, and that generating plant defense resistance through forward evolution enhances their capacity to prey on herbivores. Here, we discuss how this knowledge can be used to engineer better biocontrol agents. We argue that herbivore natural enemies which are adapted to plant chemistry will likely enhance the efficacy of future pest control efforts. Detailed phenotyping and field experiments will be necessary to quantify costs and benefits of optimizing chemical links between plants and higher trophic levels.
Collapse
Affiliation(s)
- Matthias Erb
- Institute of Plant Sciences, University of Bern, Altenbergrain 21, 3013 Bern, Switzerland.
| | - Tobias Züst
- Department of Systematic and Evolutionary Botany, University of Zürich, University of Zürich, Zollikerstrasse 107, 8008 Zürich, Switzerland
| | | |
Collapse
|
13
|
Ávila-López MB, García-Maldonado JQ, Estrada-Medina H, Hernández-Mena DI, Cerqueda-García D, Vidal-Martínez VM. First record of entomopathogenic nematodes from Yucatán State, México and their infectivity capacity against Aedes aegypti. PeerJ 2021; 9:e11633. [PMID: 34249499 PMCID: PMC8256808 DOI: 10.7717/peerj.11633] [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: 03/19/2021] [Accepted: 05/27/2021] [Indexed: 11/20/2022] Open
Abstract
Background Biological control using entomopathogenic nematodes (EPN) has demonstrated good potential to contribute to the integral control of mosquito larvae, which as adults are vectors of diseases such as Dengue fever, Zika and Chikungunya. However, until now there are no records of the presence of EPN or their killing capacity in Yucatán state, southern México. The objectives of the current study were: (1) to report the entomopathogenic nematodes present in Yucatán soils and (2) to determine the killing capacity of the most frequent and abundant EPN against Aedes aegypti mosquito larvae and the microbial community developed by Ae. Aegypti exposed to this EPN. Methods The nematodes were collected by the insect trap technique using the great wax moth Galleria mellonella. Internal transcribed spacer (ITS), 28S gene of ribosomal DNA and phylogenetic analyses were performed to identify the EPN. For the bioassay, four concentrations of the most frequent and abundant EPN were tested: 1,260:1 infective juveniles (IJs) per mosquito larvae, 2,520 IJs:1, 3,780 IJs:1 and 5,040 IJs:1. High-throughput sequencing of the 16S rRNA gene was used to identify bacterial amplicon sequences in the mosquito larvae infected with EPN. Results Six isolates of Heterorhabditis were recovered from 144 soil samples. Heterorhabditis indica (four isolates) was the most frequent and abundant EPN, followed by Heterorhabditis n. sp. (two isolates). Both nematodes are reported for the first time for Yucatán state, Mexico. The concentration of 2,520 IJs:1 produced 80% of mosquito larvae mortality in 48 h. Representative members of Photorhabdus genus were numerically dominant (74%) in mosquito larvae infected by H. indica. It is most likely that these bacteria produce secondary toxic metabolites that enhance the mortality of these mosquito larvae.
Collapse
Affiliation(s)
- Mariana B Ávila-López
- Aquatic Pathology Laboratory. Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional Unidad Mérida, Carretera Antigua a Progreso,, Mérida, Yucatán, México
| | - José Q García-Maldonado
- Aquatic Pathology Laboratory. Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional Unidad Mérida, Carretera Antigua a Progreso,, Mérida, Yucatán, México
| | - Héctor Estrada-Medina
- Facultad de Medicina Veterinaria y Zootecnia, Departamento de Manejo y Conservación de Recursos Naturales Tropicales, Campus de Ciencias Biológicas y Agropecuarias, Universidad Autónoma de Yucatán, Mérida, Yucatán, México
| | - David I Hernández-Mena
- Aquatic Pathology Laboratory. Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional Unidad Mérida, Carretera Antigua a Progreso,, Mérida, Yucatán, México
| | - Daniel Cerqueda-García
- Aquatic Pathology Laboratory. Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional Unidad Mérida, Carretera Antigua a Progreso,, Mérida, Yucatán, México
| | - Víctor M Vidal-Martínez
- Aquatic Pathology Laboratory. Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional Unidad Mérida, Carretera Antigua a Progreso,, Mérida, Yucatán, México
| |
Collapse
|
14
|
Paddock KJ, Robert CAM, Erb M, Hibbard BE. Western Corn Rootworm, Plant and Microbe Interactions: A Review and Prospects for New Management Tools. INSECTS 2021; 12:171. [PMID: 33671118 PMCID: PMC7922318 DOI: 10.3390/insects12020171] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/22/2021] [Revised: 02/11/2021] [Accepted: 02/13/2021] [Indexed: 12/12/2022]
Abstract
The western corn rootworm, Diabrotica virgifera virgifera LeConte, is resistant to four separate classes of traditional insecticides, all Bacillius thuringiensis (Bt) toxins currently registered for commercial use, crop rotation, innate plant resistance factors, and even double-stranded RNA (dsRNA) targeting essential genes via environmental RNA interference (RNAi), which has not been sold commercially to date. Clearly, additional tools are needed as management options. In this review, we discuss the state-of-the-art knowledge about biotic factors influencing herbivore success, including host location and recognition, plant defensive traits, plant-microbe interactions, and herbivore-pathogens/predator interactions. We then translate this knowledge into potential new management tools and improved biological control.
Collapse
Affiliation(s)
- Kyle J. Paddock
- Division of Plant Sciences, University of Missouri, Columbia, MO 65211, USA;
| | - Christelle A. M. Robert
- Institute of Plant Sciences, University of Bern, 3013 Bern, Switzerland; (C.A.M.R.); (M.E.)
- Oeschger Centre for Climate Change Research, University of Bern, 3013 Bern, Switzerland
| | - Matthias Erb
- Institute of Plant Sciences, University of Bern, 3013 Bern, Switzerland; (C.A.M.R.); (M.E.)
- Oeschger Centre for Climate Change Research, University of Bern, 3013 Bern, Switzerland
| | - Bruce E. Hibbard
- Plant Genetics Research Unit, United States Department of Agriculture, Agricultural Research Service, Columbia, MO 65211, USA
| |
Collapse
|