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Plasticity in Chemical Host Plant Recognition in Herbivorous Insects and Its Implication for Pest Control. BIOLOGY 2022; 11:biology11121842. [PMID: 36552352 PMCID: PMC9775997 DOI: 10.3390/biology11121842] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/15/2022] [Revised: 12/13/2022] [Accepted: 12/14/2022] [Indexed: 12/24/2022]
Abstract
Chemical communication is very important in herbivorous insects, with many species being important agricultural pests. They often use olfactory cues to find their host plants at a distance and evaluate their suitability upon contact with non-volatile cues. Responses to such cues are modulated through interactions between various stimuli of biotic and abiotic origin. In addition, the response to the same stimulus can vary as a function of, for example, previous experience, age, mating state, sex, and morph. Here we summarize recent advances in the understanding of plant localization and recognition in herbivorous insects with a focus on the interplay between long- and short-range signals in a complex environment. We then describe recent findings illustrating different types of plasticity in insect plant choice behavior and the underlying neuronal mechanisms at different levels of the chemosensory pathway. In the context of strong efforts to replace synthetic insecticides with alternative pest control methods, understanding combined effects between long- and close-range chemical cues in herbivore-plant interactions and their complex environment in host choice are crucial to develop effective plant protection methods. Furthermore, plasticity of behavioral and neuronal responses to chemical cues needs to be taken into account to develop effective sustainable pest insect control through behavioral manipulation.
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Sun LL, Liu XL, Wang YN, Berg BG, Xie GY, Chen WB, Liu Y, Wang GR, Zhao XC, Tang QB. Neuronal architecture and functional mapping of the taste center of larval Helicoverpa armigera (Lepidoptera: Noctuidae). INSECT SCIENCE 2022; 29:730-748. [PMID: 34427391 DOI: 10.1111/1744-7917.12965] [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: 04/13/2021] [Revised: 08/17/2021] [Accepted: 08/19/2021] [Indexed: 06/13/2023]
Abstract
The sense of taste plays a crucial role in herbivorous insects by discriminating nutrients from complex plant metabolic compounds. The peripheral coding of taste has been thoroughly studied in many insect species, but the central gustatory pathways are poorly described. In the present study, we characterized single neurons in the gnathal ganglion of Helicoverpa armigera larvae using the intracellular recording/staining technique. We identified different types of neurons, including sensory neurons, interneurons, and motor neurons. The morphologies of these neurons were largely diverse and their arborizations seemingly covered the whole gnathal ganglion. The representation of the single neurons responding to the relevant stimuli of sweet and bitter cues showed no distinct patterns in the gnathal ganglion. We postulate that taste signals may be processed in a manner consistent with the principle of population coding in the gnathal ganglion of H. armigera larvae.
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Affiliation(s)
- Long-Long Sun
- Department of Entomology, College of Plant Protection, Henan Agricultural University, Zhengzhou, 450002, China
| | - Xiao-Lan Liu
- Department of Entomology, College of Plant Protection, Henan Agricultural University, Zhengzhou, 450002, China
| | - Ya-Nan Wang
- Department of Entomology, College of Plant Protection, Henan Agricultural University, Zhengzhou, 450002, China
| | - Bente G Berg
- Chemosensory laboratory, Department of Psychology, Norwegian University of Science and Technology, Trondheim, 7489, Norway
| | - Gui-Ying Xie
- Department of Entomology, College of Plant Protection, Henan Agricultural University, Zhengzhou, 450002, China
| | - Wen-Bo Chen
- Department of Entomology, College of Plant Protection, Henan Agricultural University, Zhengzhou, 450002, China
| | - Yang Liu
- State Key Laboratory for Biology of Plant Disease and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, 100193, China
| | - Gui-Rong Wang
- State Key Laboratory for Biology of Plant Disease and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, 100193, China
| | - Xin-Cheng Zhao
- Department of Entomology, College of Plant Protection, Henan Agricultural University, Zhengzhou, 450002, China
| | - Qing-Bo Tang
- Department of Entomology, College of Plant Protection, Henan Agricultural University, Zhengzhou, 450002, China
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Sun L, Hou W, Zhang J, Dang Y, Yang Q, Zhao X, Ma Y, Tang Q. Plant Metabolites Drive Different Responses in Caterpillars of Two Closely Related Helicoverpa Species. Front Physiol 2021; 12:662978. [PMID: 33967833 PMCID: PMC8098809 DOI: 10.3389/fphys.2021.662978] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2021] [Accepted: 03/16/2021] [Indexed: 11/17/2022] Open
Abstract
The host acceptances of insects can be determined largely by detecting plant metabolites using insect taste. In the present study, we investigated the gustatory sensitivity and feeding behaviors of two closely related caterpillars, the generalist Helicoverpa armigera (Hübner) and the specialist H. assulta (Guenée), to different plant metabolites by using the single sensillum recording technique and the dual-choice assay, aiming to explore the contribution of plant metabolites to the difference of diet breadth between the two species. The results depicted that the feeding patterns of caterpillars for both plant primary and secondary metabolites were significantly different between the two Helicoverpa species. Fructose, glucose, and proline stimulated feedings of the specialist H. assulta, while glucose and proline had no significant effect on the generalist H. armigera. Gossypol and tomatine, the secondary metabolites of host plants of the generalist H. armigera, elicited appetitive feedings of this insect species but drove aversive feedings of H. assulta. Nicotine and capsaicin elicited appetitive feedings of H. assulta, but drove aversive feedings of H. armigera. For the response of gustatory receptor neurons (GRNs) in the maxillary styloconic sensilla of caterpillars, each of the investigated primary metabolites induced similar responding patterns between the two Helicoverpa species. However, four secondary metabolites elicited different responding patterns of GRNs in the two species, which is consistent with the difference of feeding preferences to these compounds. In summary, our results of caterpillars’ performance to the plant metabolites could reflect the difference of diet breadth between the two Helicoverpa species. To our knowledge, this is the first report showing that plant secondary metabolites could drive appetitive feedings in a generalist insect species, which gives new insights of underscoring the adaptation mechanism of herbivores to host plants.
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Affiliation(s)
- Longlong Sun
- The Institute of Chemical Ecology and College of Plant Protection, Henan Agricultural University, Zhengzhou, China
| | - Wenhua Hou
- The Institute of Chemical Ecology and College of Plant Protection, Henan Agricultural University, Zhengzhou, China
| | - Jiajia Zhang
- The Institute of Chemical Ecology and College of Plant Protection, Henan Agricultural University, Zhengzhou, China
| | - Yuli Dang
- College of Agronomy, Henan Agricultural University, Zhengzhou, China
| | - Qiuyun Yang
- College of Agronomy, Henan Agricultural University, Zhengzhou, China
| | - Xincheng Zhao
- The Institute of Chemical Ecology and College of Plant Protection, Henan Agricultural University, Zhengzhou, China
| | - Ying Ma
- College of Agronomy, Henan Agricultural University, Zhengzhou, China
| | - Qingbo Tang
- The Institute of Chemical Ecology and College of Plant Protection, Henan Agricultural University, Zhengzhou, China
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Tang QB, Song WW, Chang YJ, Xie GY, Chen WB, Zhao XC. Distribution of Serotonin-Immunoreactive Neurons in the Brain and Gnathal Ganglion of Caterpillar Helicoverpa armigera. Front Neuroanat 2019; 13:56. [PMID: 31191263 PMCID: PMC6547022 DOI: 10.3389/fnana.2019.00056] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2019] [Accepted: 05/14/2019] [Indexed: 02/05/2023] Open
Abstract
Serotonin (5-hydroxytryptamine, 5-HT) is an important biogenic amine that acts as a neural circuit modulator. It is widespread in the central nervous system of insects. However, little is known about the distribution of serotonin in the nervous system of the cotton bollworm Helicoverpa armigera. In the present study, we performed immunohistochemical experiments with anti-serotonin serum to examine the distribution of serotonin in the central nervous system of H. armigera larvae. We found about 40 serotonin-immunoreactive neurons in the brain and about 20 in the gnathal ganglion. Most of these neurons are wide-field neurons giving rise to processes throughout the neuropils of the brain and the gnathal ganglion. In the central brain, serotonin-immunoreactive processes are present bilaterally in the tritocerebrum, the deutocerebrum, and major regions of the protocerebrum, including the central body (CB), lateral accessory lobes (LALs), clamps, crepine, superior protocerebrum, and lateral protocerebrum. The CB, anterior ventrolateral protocerebrum (AVLP), and posterior optic tubercle (POTU) contain extensive serotonin-immunoreactive process terminals. However, the regions of mushroom bodies, the lateral horn, and protocerebral bridges (PBs) are devoid of serotonin-immunoreactivity. In the gnathal ganglion, the serotonin-immunoreactive processes are also widespread throughout the neuropil, and some process projections extend to the tritocerebrum. Our results provide the first comprehensive description of the serotonergic neuronal network in H. armigera larvae, and they reveal the neural architecture and the distribution of neural substances, allowing us to explore the neural mechanisms of behaviors by using electrophysiological and pharmacological approaches on the target regions.
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Affiliation(s)
- Qing-Bo Tang
- Department of Entomology, College of Plant Protection, Henan Agricultural University, Zhengzhou, China
| | - Wei-Wei Song
- Department of Entomology, College of Plant Protection, Henan Agricultural University, Zhengzhou, China
| | - Ya-Jun Chang
- Department of Entomology, College of Plant Protection, Henan Agricultural University, Zhengzhou, China
| | - Gui-Ying Xie
- Department of Entomology, College of Plant Protection, Henan Agricultural University, Zhengzhou, China
| | - Wen-Bo Chen
- Department of Entomology, College of Plant Protection, Henan Agricultural University, Zhengzhou, China
| | - Xin-Cheng Zhao
- Department of Entomology, College of Plant Protection, Henan Agricultural University, Zhengzhou, China
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Wang Y, Ma Y, Zhou DS, Gao SX, Zhao XC, Tang QB, Wang CZ, van Loon JJA. Higher plasticity in feeding preference of a generalist than a specialist: experiments with two closely related Helicoverpa species. Sci Rep 2017; 7:17876. [PMID: 29259307 PMCID: PMC5736596 DOI: 10.1038/s41598-017-18244-7] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2017] [Accepted: 12/07/2017] [Indexed: 11/23/2022] Open
Abstract
Herbivorous insects have been categorized as generalists or specialists depending on the taxonomic relatedness of the plants they use as food or oviposition substrates. The plasticity in host plant selection behavior of species belonging to the two categories received little attention. In the present work, fifth instar caterpillars of the generalist herbivore Helicoverpa armigera and its closely related species, the specialist Helicoverpa assulta, were fed on common host plants or artificial diet, after which their feeding preference was assessed individually by using dual - and triple- plant choice assays. Results show both the two Helicoverpa species have a preference hierarchy for host plants. Compared to the fixed preference hierarchy of the specialist H. assulta, the generalist H. armigera exhibited extensive plasticity in feeding preference depending on the host plant experienced during larval development. Whereas the specialist H. assulta exhibited a rigid preference in both dual and triple-plant choice assays, our findings demonstrate that the generalist H. armigera expressed stronger preferences in the dual-plant choice assay than in the triple-plant choice assay. Our results provide additional evidence supporting the neural constraints hypothesis which predicts that generalist herbivores make less accurate decisions than specialists when selecting plants.
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Affiliation(s)
- Yan Wang
- The Institute of Chemical Ecology & College of Plant Protection, Henan Agricultural University, Zhengzhou, 450002, China
| | - Ying Ma
- The Institute of Chemical Ecology & College of Plant Protection, Henan Agricultural University, Zhengzhou, 450002, China
| | | | - Su-Xia Gao
- Institute of Plant Protection, Henan Academy of Agricultural Sciences, Zhengzhou, 450002, China
| | - Xin-Cheng Zhao
- The Institute of Chemical Ecology & College of Plant Protection, Henan Agricultural University, Zhengzhou, 450002, China
| | - Qing-Bo Tang
- The Institute of Chemical Ecology & College of Plant Protection, Henan Agricultural University, Zhengzhou, 450002, China.
| | - Chen-Zhu Wang
- State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology, Chinese Academy of Sciences, Beijing, 100101, China
| | - Joop J A van Loon
- Laboratory of Entomology, Wageningen University, Droevendaalsesteeg 1, 6708 PB, Wageningen, The Netherlands.
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