Acta Entomologica Sinica ›› 2022, Vol. 65 ›› Issue (3): 386-398.doi: 10.16380/j.kcxb.2022.03.013

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Research progress of the mechanism of CO2 perception in insects

CHEN Qiu-Yan, LIU Yang*, WANG Gui-Rong*   

  1. (State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing 100193, China)
  • Online:2022-03-20 Published:2022-03-24

Abstract:  Carbon dioxide (CO2) is an important component of air. It is not only one of the main raw materials for plant photosynthesis, but also directly affects the life activities of insects as a chemical signal. CO2 plays an important role in the foraging behavior of Diptera, Coleoptera and Lepidoptera. CO2 can affect the oviposition behavior of flies and moths. CO2 is an important indicator for social insects to adjust the climatic conditions in the nest. The research on the mechanism of CO2 perception in insects can help to better understand the chemosensory systems in insects, and may also provide some new strategies for pest monitoring and control. Since the two CO2 receptor genes GR21a and GR63a co-expressed in Drosophilia were indentified in 2017, CO2 receptor genes of many insect species have been identified with the development of high-throughput sequencing techniques combined with sequence homology analysis. For this reason, the major breakthrough has been made in the research for the mechanism of CO2 perception at the peripheral nervous system level in insects. The CO2 receptor genes of insects are expressed on specific receptor neurons, which have the ability of sensing small fluctuations in the external CO2 in the environment and further transmit the CO2 signal to the central nervous system of the brain. The transduction of CO2 signal in the central nervous system can be divided into the processing in the primary brain center-antennal lobe and the processing in the higher brain center in insects. CO2-projecting neurons form complex dendrites within specific glomerulus in the antennal lobe, and then continue to project toward the lateral horn and upward to the mushroom body of the higher centers in the brain. Homologous genes of CO2 receptor genes have not been identified in the genomes of some insects, but the responses of these insects to CO2 have been reported earlier, suggesting that other pathways sensing CO2 exist in these insects. We summarized the related research progress from four aspects: the importance of CO2 for the life activities of insects, the mechanism of CO2 perception at the peripheral level in insects, the mechanism of CO2 perception at the central nervous system level in insects, and other CO2 perception pathways in insects. We also emphatically introduced the effects of CO2 on insects and the identification and functional research of CO2 receptor genes, providing some useful ideas and methods for the further study on the mechanism of CO2 perception and the development of green prevention and control.

Key words: CO2, perception mechanism, gustatory receptor, receptor neuron, functional characterization