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The migratory brown planthopper (BPH), Nilaparvata lugens (Hemiptera: Delphacidae), is the most destructive pest affecting rice plants in Asia and feeds exclusively on rice. Studies have investigated the olfactory response of BPHs to the major rice volatile compounds in rice. The insect olfactory co-receptor (Orco) is a crucial component of the olfactory system and is essential for odorant detection. Functional analysis of the Orco gene in BPHs would aid in the identification of their host preference.We identified the BPH Orco homologue (NlOrco) by Blast searching the BPH transcriptome with the Drosophila Orco gene sequence. Spatiotemporal analysis indicated that NlOrco is first expressed in the later egg stage, and is expressed mainly in the antennae in adult females. A NlOrco-knockout line (NlOrcoOur findings indicated that BPHs exhibit strong olfactory responses to major rice volatile compounds and suggest that NlOrco is required for the maximal fitness of BPHs. Our results may facilitate the identification of potential target genes or chemical compounds for BPH control applications. © 2022 Society of Chemical Industry.

A wheel-step driving system that can realise a wheel-step driving mode is proposed to improve the tractive performances of wheeled unmanned vehicles when driving on soft roads. Although the wheel-step driving system proposed in this paper adopts double wishbone suspension, it also can be applied for different suspension configurations after adjustment. In this paper, a typical sandy soil and a designated tyre are selected as hypotheses to verify the enhanced effect of wheel-step driving system on tractive performance. First, the wheel-soil interaction mechanism of the wheel-step driving mode is analysed based on terramechanics theory and the wheel-step driving strategy is optimised. The tractive performances of the wheel-step driving mode and the normal driving mode are compared and analysed through numerical calculations. Then, a soil model is established using discrete element software and a wheel model is established using dynamics software; the coupled simulation of the dynamic and discrete elements compares the drawbar pull, the driving torque and the sinkage in the normal driving mode, the wheel-step driving mode and the optimised wheel-step driving mode. The simulation data verify the effectiveness of the optimisation strategy used and the enhancement effect of the wheel-step driving mode on the traction performance. Finally, a soil-bin test system is built and a tractive performance experiment is performed. The experimental data and the simulation data show good agreement, thus verifying the correctness of the simulation model.

The nonbiting midges are tiny insects with a wide distribution around West Lake, China. In this study, the seasonal dynamics of the local dominant midge species was investigated. Phylogenetic trees of this species also were analyzed to discover its evolutionary history. Ultraviolet (UV) light traps were used for surveillance around West Lake in the period from April 2017 to November 2018. External morphological identification was performed using a stereomicroscope. Two genes of adult female midges that encoded the cytochrome oxidase subunit I (COI) and internal transcribed spacer 1 (ITS-1) were sequenced and aligned online using GenBank nucleotide database and the Molecular Evolutionary Genetics Analysis (MEGA) software 10.1.7. According to the field surveillance in 2017–2018, Forcipomyia bikanni Chan and LeRoux (Diptera: Ceratopogonidae) is the representative dominant species of West Lake, with its activity peaking in August and October. The COI and ITS-1 gene sequences of F. bikanni (XH01-5) were 523 bp and 315 bp, respectively. The final phylogenetic tree of the COI implied that F. bikanni (XH01-5) has 97.9% significant similarity with conspecific F. bikanni (LC015045) from the adjacent Fujian Province, China (E-value ≤ 0.1%). Furthermore, the ITS-1 sequences with 98% likelihood showed the highest linkage between F. bikanni (XH01-5) and F. townsvillensis (Taylor) (HM775502-HM775504) with different branches. Thus, the final unrooted phylogenetic trees of COI and ITS-1 are essential tools for reconstructing the evolutionary histories of nonbiting midges.

The forkhead box O (FoxO) protein is the main transcriptional effector downstream of the insulin/insulin-like signaling pathway and regulates many developmental and physiological processes. Holometabolous insects with loss-of-function mutations in FoxO exhibit phenotypes distinct from those of hemimetabolous insects in which RNA interference was used. Despite the functional importance of FoxO, whether hemimetabolous insects share an evolutionally conserved function of FoxO with holometabolous insects remains to be clarified. We used the clustered regularly interspaced short palindromic repeats/CRISPR-associated 9 (CRISPR/Cas9) genome editing-system to establish a homozygous FoxO-null mutant (NlFoxO

To validate a response surface model for the inhibition of somatic motor response at corrected body weight (CBW) doses of remifentanil plus propofol in elderly patients and to analyze the dose-effect relationship and optimal dosing range for total intravenous anesthesia (TIVA) induction in painless gastroscopy.We designed a prospective, open-ended, randomized, parallel group study. A total of 300 elderly patients undergoing painless gastroscopy were randomized to receive remifentanil (0-0.5 μg/kg) and propofol (0.8-2.2 mg/kg) dosing based on CBW. Gastroscopy was performed at the drug's peak effect time. The somatic motor response to gastroscopic stimulation and the adverse reactions at different points were recorded. The somatic motor response was used as the basic element in the subsequent RSM analysis. Model parameters and 95% confidence intervals were fitted by MATLAB software.The CBW doses of remifentanil and propofol showed synergistic inhibitory effects on motor response to noxious stimulation and attenuated adverse reactions. The 50% effective doses of remifentanil and propofol for inhibiting the motor response were 1.754 μg/kg and 2.048 mg/kg, respectively.Remifentanil or propofol alone could not inhibit the somatic motor response at weight-adjusted doses among elderly patients. A combination of remifentanil and propofol showed a synergistic interaction in suppressing the motor response and adverse reactions in elderly patients. Preinjection of remifentanil could reduce the needed dose of propofol.

The homeotic complex gene Abdominal-B (Abd-B) is involved in regulating the development of posterior abdomens and has been extensively studied in holometabolous insects. However, the function of Abd-B in hemimetabolous insects is not fully understood. Here, we functionally characterize an Abd-B homologue in the brown planthopper (BPH), Nilaparvata lugens. The full-length cDNA of the N. lugens Abd-B homologue (NlAbd-B) is 2334 nt, with an open reading frame of 1113 bp. NlAbd-B has the highest expression level at the egg stage relative to the nymphal and adult stages and is mainly expressed in the fourth to the ninth abdominal segment of embryos. RNA interference (RNAi)-mediated knockdown of NlAbd-B in nymphs disrupted the development of genitalia both in females and males and caused a genitalia-to-leg transformation. Parental RNAi of NlAbd-B in both female and male adults caused an extra abdominal segment in offspring nymphs, while parental RNAi of the N. lugens abdominal-A homologue in both female and males adults led to embryos with leg-like appendages on the second to the eighth abdominal segment. These findings suggest that NlAbd-B plays a pivotal role in genital development and posterior abdominal patterning and thus highlight the conservational role of Abd-B in holometabolous and hemimetabolous insects.