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Christensen T, Dyer LA, Forister ML, Bowers MD, Carper A, Teglas MB, Hurtado P, Smilanich AM. Host plant-mediation of viral transmission and its consequences for a native butterfly. Ecology 2024; 105:e4282. [PMID: 38483138 DOI: 10.1002/ecy.4282] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/03/2023] [Revised: 11/11/2023] [Accepted: 01/18/2024] [Indexed: 04/04/2024]
Abstract
Pathogens play a key role in insect population dynamics, contributing to short-term fluctuations in abundance as well as long-term demographic trends. Two key factors that influence the effects of entomopathogens on herbivorous insect populations are modes of pathogen transmission and larval host plants. In this study, we examined tritrophic interactions between a sequestering specialist lepidopteran, Euphydryas phaeton, and a viral pathogen, Junonia coenia densovirus, on its native host plant, Chelone glabra, and a novel host plant, Plantago lanceolata, to explore whether host plant mediates viral transmission, survival, and viral loads. A two-factor factorial experiment was conducted in the laboratory with natal larval clusters randomly assigned to either the native or novel host plant and crossed with either uninoculated controls or viral inoculation (20% of individuals in the cluster inoculated). Diapausing clusters were overwintered in the laboratory and checked weekly for mortality. At the end of diapause, all surviving individuals were reared to adulthood to estimate survivorship. All individuals were screened to quantify viral loads, and estimate horizontal transmission postmortem. To test for vertical transmission, adults were mated, and the progeny were screened for viral presence. Within virus-treated groups, we found evidence for both horizontal and vertical transmission. Larval clusters reared on the native host plant had slightly higher horizontal transmission. Survival probability was lower in clusters feeding on the native host plant, with inoculated groups reared on the native host plant experiencing complete mortality. Viral loads did not differ by the host plant, although viral loads decreased with increased sequestration of secondary compounds on both host plants. Our results indicate that the use of a novel host plant may confer fitness benefits in terms of survival and reduced viral transmission when larvae feeding on it are infected with this pathogen, supporting hypotheses of potential evolutionary advantages of a host range expansion in the context of tritrophic interactions.
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Affiliation(s)
- Tara Christensen
- Program in Ecology, Evolution, and Conservation Biology, University of Nevada, Reno, Nevada, USA
- Department of Biology, University of Nevada, Reno, Nevada, USA
| | - Lee A Dyer
- Program in Ecology, Evolution, and Conservation Biology, University of Nevada, Reno, Nevada, USA
- Department of Biology, University of Nevada, Reno, Nevada, USA
| | - Matthew L Forister
- Program in Ecology, Evolution, and Conservation Biology, University of Nevada, Reno, Nevada, USA
- Department of Biology, University of Nevada, Reno, Nevada, USA
| | - M Deane Bowers
- Department of Ecology and Evolutionary Biology and Museum of Natural History, University of Colorado, Boulder, Boulder, Colorado, USA
| | - Adrian Carper
- Department of Ecology and Evolutionary Biology and Museum of Natural History, University of Colorado, Boulder, Boulder, Colorado, USA
| | - Mike B Teglas
- Program in Ecology, Evolution, and Conservation Biology, University of Nevada, Reno, Nevada, USA
- Department of Agriculture, Veterinary and Rangeland Sciences, University of Nevada, Reno, Nevada, USA
| | - Paul Hurtado
- Program in Ecology, Evolution, and Conservation Biology, University of Nevada, Reno, Nevada, USA
- Department of Mathematics and Statistics, University of Nevada, Reno, Nevada, USA
| | - Angela M Smilanich
- Program in Ecology, Evolution, and Conservation Biology, University of Nevada, Reno, Nevada, USA
- Department of Biology, University of Nevada, Reno, Nevada, USA
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Gallon ME, Muchoney ND, Smilanich AM. Viral Infection Induces Changes to the Metabolome, Immune Response and Development of a Generalist Insect Herbivore. J Chem Ecol 2024; 50:152-167. [PMID: 38353894 DOI: 10.1007/s10886-024-01472-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2023] [Revised: 01/15/2024] [Accepted: 01/20/2024] [Indexed: 04/25/2024]
Abstract
Host plant consumption and pathogen infection commonly influence insect traits related to development and immunity, which are ultimately reflected in the behavior and physiology of the insect. Herein, we explored changes in the metabolome of a generalist insect herbivore, Vanessa cardui (Lepidoptera: Nymphalidae), in response to both dietary variation and pathogen infection in order to gain insight into tritrophic interactions for insect metabolism and immunity. Caterpillars were reared on two different host plants, Plantago lanceolata (Plantaginaceae) and Taraxacum officinale (Asteraceae) and subjected to a viral infection by Junonia coenia densovirus (JcDV), along with assays to determine the insect immune response and development. Richness and diversity of plant and caterpillar metabolites were evaluated using a liquid chromatography-mass spectrometry approach and showed that viral infection induced changes to the chemical content of V. cardui hemolymph and frass dependent upon host plant consumption. Overall, the immune response as measured by phenoloxidase (PO) enzymatic activity was higher in individuals feeding on P. lanceolata compared with those feeding on T. officinale. Additionally, infection with JcDV caused suppression of PO activity, which was not host plant dependent. We conclude that viral infection combined with host plant consumption creates a unique chemical environment, particularly within the insect hemolymph. Whether and how these metabolites contribute to defense against viral infection is an open question in chemical ecology.
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Affiliation(s)
- Marilia Elias Gallon
- Department of Biology, University of Nevada, 1664 N. Virginia St., Reno, NV, 89557, USA.
- Núcleo de Pesquisa em Produtos Naturais e Sintéticos, School of Pharmaceutical Sciences of Ribeirão Preto, University of São Paulo (USP), Av. do Café s/n°, Ribeirão Preto, SP, 14040-903, Brazil.
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Yi C, Teng D, Xie J, Tang H, Zhao D, Liu X, Liu T, Ding W, Khashaveh A, Zhang Y. Volatiles from cotton aphid ( Aphis gossypii) infested plants attract the natural enemy Hippodamia variegata. FRONTIERS IN PLANT SCIENCE 2023; 14:1326630. [PMID: 38173929 PMCID: PMC10761428 DOI: 10.3389/fpls.2023.1326630] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/23/2023] [Accepted: 12/07/2023] [Indexed: 01/05/2024]
Abstract
The Aphis gossypii is a major threat of cotton worldwide due to its short life cycle and rapid reproduction. Chemical control is the primary method used to manage the cotton aphid, which has significant environmental impacts. Therefore, prioritizing eco-friendly alternatives is essential for managing the cotton aphid. The ladybird, Hippodamia variegata, is a predominant predator of the cotton aphid. Its performance in cotton plantation is directly linked to chemical communication, where volatile compounds emitted from aphid-infested plants play important roles in successful predation. Here, we comprehensively studied the chemical interaction between the pest, natural enemy and host plants by analyzing the volatile profiles of aphid-infested cotton plants using gas chromatography-mass spectrometry (GC-MS). We then utilized the identified volatile compounds in electrophysiological recording (EAG) and behavioral assays. Through behavioral tests, we initially demonstrated the clear preference of both larvae and adults of H. variegata for aphid-infested plants. Subsequently, 13 compounds, namely α-pinene, cis-3-hexenyl acetate, 4-ethyl-1-octyn-3-ol, β-ocimene, dodecane, E-β-farnesene, decanal, methyl salicylate, β-caryophyllene, α-humulene, farnesol, DMNT, and TMTT were identified from aphid-infested plants. All these compounds were electrophysiologically active and induced detectable EAG responses in larvae and adults. Y-tube olfactometer assays indicated that, with few exceptions for larvae, all identified chemicals were attractive to H. variegata, particularly at the highest tested concentration (100 mg/ml). The outcomes of this study establish a practical foundation for developing attractants for H. variegata and open avenues for potential advancements in aphid management strategies by understanding the details of chemical communication at a tritrophic level.
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Affiliation(s)
- Chaoqun Yi
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, China
- Key Laboratory of Entomology and Pest Control Engineering, College of Plant Protection, Southwest University, Chongqing, China
| | - Dong Teng
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, China
- Key Laboratory of Integrated Management of Crop Diseases and Pests (Ministry of Education), College of Plant Protection, Nanjing Agricultural University, Nanjing, China
| | - Jiaoxin Xie
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, China
- College of Animal Science, Shanxi Agricultural University, Jinzhong, China
| | - Haoyu Tang
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, China
- Key Laboratory of Entomology and Pest Control Engineering, College of Plant Protection, Southwest University, Chongqing, China
| | - Danyang Zhao
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, China
- School of Resources and Environment, Henan Institute of Science and Technology, Xinxiang, China
| | - Xiaoxu Liu
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, China
- National Key Laboratory of Green Pesticide, College of Plant Protection, South China Agricultural University, Guangzhou, China
| | - Tinghui Liu
- College of Plant Protection, Hebei Agricultural University, Baoding, China
| | - Wei Ding
- Key Laboratory of Entomology and Pest Control Engineering, College of Plant Protection, Southwest University, Chongqing, China
| | - Adel Khashaveh
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Yongjun Zhang
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, China
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