Behavioural regulator and molecular reception of a double‐edge‐sword hunter beetle

Abstract

BACKGROUND: The black carabid beetle Calosoma maximoviczi is a successful predator that serves as both a beneficial insect and a severe threat to economic herbivores. Its hunting technique relies heavily on olfaction, but the underlying mechanism has not been studied. Here, we report the electrophysiological, ecological and molecular traits of bioactive components identified from a comprehensive panel of natural odorants in the beetle-prey-plant system. The aim of this work was to investigate olfactory perceptions and their influence on the behaviours of C. maximoviczi.RESULTS: Among the 200 identified volatiles, 18 were concentrated in beetle and prey samples, and 14 were concentrated in plants. Insect feeding damage to plants led to a shift in the emission fingerprint. Twelve volatiles were selected using successive electrophysiological tests. Field trials showed that significant sex differences existed when trapping with a single chemical or chemical mixture. Expression profiles indicated that sex-biased catches were related to the expression of 15 annotated CmaxOBPs and 40 CmaxORs across 12 chemosensory organs. In silico evaluations were conducted with 16 CmaxORs using modelling and docking. Better recognition was predicted for the pairs CmaxOR5-(Z)-3-hexenyl acetate, CmaxOR6-⊎-caryophyllene, CmaxOR18-(E)-⊎-ocimene and CmaxOR18-tetradecane, with higher binding affinity and a suitable binding pocket. Lastly, 168Y in CmaxOR6 and 142Y in CmaxOR18 were predicted as key amino acid residues for binding ⊎-caryophyllene and tetradecane, respectively. CONCLUSION: This work provides an example pipeline for de novo investigation in C. maximoviczi baits and the underlying olfactory perceptions. The results will benefit the future development of trapping-based integrated pest management strategies and the deorphanization of odorant receptors in ground beetles.

iORandLigandDB: A Website for Three-Dimensional Structure Prediction of Insect Odorant Receptors and Docking with Odorants

“…We found that beta-Caryophyllene had the lowest average binding energy (−9.99 kcal/mol) among the 46 ligands, and Methyl isothiocyanate had the highest average binding energy (−2.53 kcal/mol) (see Table S5 for details). Beta-Caryophyllene is associated with odorant recognition, which has been often reported in important Lepidoptera pests such as Spodoptera littoralis , Spodoptera exigua , Helicoverpa armigera , and Eriocrania semipurpurella [ 54 , 55 , 56 , 57 ], important Diptera pests such as Bactrocera dorsalis and Aedes aegypti [ 58 , 59 ], Hymenoptera insects such as Anastatus japonicas [ 60 ], Coleoptera insects such as Calosoma maximoviczi and Anthonomus rubi [ 61 , 62 ], and Hemiptera pests such as Adelphocoris lineolatus , Apolygus lucorum , and Diaphorina citri [ 63 , 64 , 65 ]. Methyl isothiocyanate is an important novel soil fumigant pesticide [ 66 , 67 ], which showed a low binding degree as expected.…”

The role of tetradecane in the identification of host plants by the mirid bugs Apolygus lucorum and Adelphocoris suturalis and potential application in pest management

“…Some herbivore-infested plants produce tetradecane, which acts as kairomone to attract the pest’s natural enemies ( Li et al, 2022 ). It has been reported as an attractive plant volatile for several insect pests ( Mu et al, 2012 ; Mitra et al, 2020 ; Chen et al, 2022 ; Guo et al, 2022 ). There is, however, scant evidence from earlier investigations that it is an attractant for mirid bugs.…”

Molecular and Functional Characterization of Three General Odorant-Binding Protein 2 Genes in Cydia pomonella (Lepidoptera: Tortricidae)

“…The binding patterns between the two CpomGOBP2 proteins and their odorant molecule ligands, as well as the key binding sites, were visualized using MOE. The detailed steps of molecular docking were described in the previous study [55].…”