Herbivorous insects rely on volatile chemical cues from host plants to locate food sources and oviposition sites. General odorant binding proteins (GOBPs) are believed to be involved in the detection of host plant volatiles. In the present study, one GOBP gene, ScinGOBP2, was cloned from the antennae of adult Semiothisa cinerearia. Reverse-transcription PCR and real-time quantitative PCR analysis revealed that the expression of ScinGOBP2 was strongly biased towards the female antennae. Fluorescence-based competitive binding assays revealed that 8 of the 27 host plant volatiles, including geranyl acetone, decanal, cis-3-hexenyl n-valerate, cis-3-hexenyl butyrate, 1-nonene, dipentene, α-pinene and β-pinene, bound to ScinGOBP2 (KD = 2.21–14.94 μM). The electrical activities of all eight ScinGOBP2 ligands were confirmed using electroantennography. Furthermore, oviposition preference experiments showed that eight host volatiles, such as decanal, cis-3-hexenyl n-valerate, cis-3-hexenyl butyrate, and α-pinene, had an attractive effect on female S. cinerearia, whereas geranyl acetone, 1-nonene, β-pinene, and dipentene inhibited oviposition in females. Consequently, it can be postulated that ScinGOBP2 may be implicated in the perception of host plant volatiles and that ScinGOBP2 ligands represent significant semiochemicals mediating the interactions between plants and S. cinerearia. This insight could facilitate the development of a chemical ecology-based approach for the management of S. cinerearia.
Chemosensory proteins (CSPs) have been identified in the sensory tissues of various insect species and are believed to be involved in chemical communication in insects. However, the physiological roles of CSPs in Halyomorpha halys, a highly invasive insect species, are rarely reported. Here, we focused on one of the antennal CSPs (HhalCSP15) and determined whether it was involved in olfactory perception. Reverse transcription PCR (RT-PCR) and quantitative real-time PCR (qRT-PCR) analysis showed that HhalCSP15 was enriched in nymph and male and female adult antennae, indicating its possible involvement in the chemosensory process. Fluorescence competitive binding assays revealed that three of 43 natural compounds showed binding abilities with HhalCSP15, including β-ionone (Ki=11.9±0.6μM), cis-3-hexen-1-yl benzoate (Ki=10.5±0.4μM), and methyl (2E,4E,6Z)-decatrienoate (EEZ-MDT; Ki=9.6±0.8μM). Docking analysis supported the experimental affinity for the three ligands. Additionally, the electrophysiological activities of the three ligands were further confirmed using electroantennography (EAG). EEZ-MDT is particularly interesting, as it serves as a kairomone when H. halys forages for host plants. We therefore conclude that HhalCSP15 might be involved in the detection of host-related volatiles. Our data provide a basis for further investigation of the physiological roles of CSPs in H. halys, and extend the olfactory function of CSPs in stink bugs.
Drosophila suzukii is a major pest of sweet cherries. In this study, we evaluated its oviposition preferences across six cherry cultivars and assessed the effects of the fruit traits on its growth and development. Significant differences in the color, firmness, and sugar content were observed among the cultivars and ripeness stages. The highest oviposition rates were recorded for the “Hongdeng” (HD) and “Burlat” (BLT) cultivars in both the non-choice (HD: 31.9 ± 2.0 eggs/cherry; BLT: 31.3 ± 1.9 eggs/cherry) and choice (HD: 32.4 ± 3.2 eggs/cherry; BLT: 27.6 ± 1.9 eggs/cherry) tests, largely influenced by the fruit color. While the developmental parameters showed slight variation across the cultivars, significant differences were observed in the pupation rates (ranging from 0.80 to 0.89) and survival rates (ranging from 0.51 to 0.62), with both parameters being the highest for the “Hongdeng” cultivar. The correlation analysis revealed that a darker fruit color—characterized by lower lightness (L*), lower chromaticity (b*), and a higher color index for red grapes (CIRG)—positively influenced the oviposition and pupation rates. Although the other correlations were not significant, the oviposition and developmental parameters were positively correlated with sweetness and negatively correlated with firmness. These findings enhance our understanding of how cherry traits influence D. suzukii behavior, providing critical insights for pest management strategies in cherry production.
The brown marmorated stink bug, Halyomorpha halys, has become a severe threat to agriculture worldwide with continuous invasion and spread. Sulfoxaflor is the pioneering sulfoximine insecticide and has been widely employed for managing sap-feeding insect pests across diverse crops. However, the sublethal effects of sulfoxaflor on the growth and reproduction of H. halys remain unexplored. This study employed age-stage life tables and physiological parameters to evaluate the sublethal effects of sulfoxaflor on H. halys. The bioassay results indicated that the LC20 and LC50 values of sulfoxaflor against second-instar nymphs of H. halys were 7.75 and 20.97 mg/L, respectively. Treatment with the LC20 concentration of sulfoxaflor reduced the lifespan of female adults by 11.74 days. Importantly, the oviposition period of females was shortened by 9.47 days, and the fecundity was decreased by 1.4-fold. Additionally, the activities of cytochrome P450 (P450s) and glutathione S-transferase (GSTs) enzymes in H. halys were enhanced 1.40 and 1.54 times after treatment with sublethal concentrations of sulfoxaflor. These findings demonstrate that sublethal concentrations of sulfoxaflor significantly inhibit the population development of H. halys. Moreover, the detoxification enzymes P450s and GSTs may be associated with the potential resistance to sulfoxaflor in H. halys. This information provides valuable insights into the application of sulfoxaflor in the management of this pest.