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Abstract Next-generation sequencing allows for fine-scale studies of microbial communities. Herein, 16S ribosomal RNA high-throughput sequencing was used to identify, classify, and predict the functions of the bacterial communities in the eggs and ovaries of Bactrocera cucurbitae (Coquillett) (Diptera: Tephritidae), which is a pest that infests a variety of cucurbit fruits at different developmental stages. Taxonomic analyses indicate that bacteria associated with B. cucurbitae represent 19 phyla, which were spread across different developmental stages. Specifically, the egg microbiota had a higher alpha diversity than those of microbiota in the primary and mature ovaries. Significant differences were not observed between the primary and mature ovaries in terms of their microbiota’s alpha diversities. Pseudomonadota, Deinococcota, Bacteroidota, Bacillota, and Actinomycetota were the dominant phyla in all three developmental stages of B. cucurbitae, and Pseudomonadaceae and Enterobacteriaceae were the most abundant families. Owing to the unique physiological environment of the ovaries, the diversity of their bacterial community was significantly lower than that in the eggs. This study provides new insights into the structure and abundance of the microbiota in B. cucurbitae at different developmental stages and contributes to forming management strategies for this pest.

Maglev vehicles apply the entire vehicle load uniformly onto bridges through levitation forces. In assessing the dynamic characteristics of the maglev train–bridge coupling system, it is reasonable to simplify the distributed levitation force as a concentrated force. This article theoretically derives the analytical response of bridge dynamics under the action of a single constant force and conducts numerical simulations for a moving single constant force and a series of equally spaced constant forces passing over simply supported beams and two-span continuous beams, respectively. The topic of discussion is the response of bridge dynamics when different degrees of force concentration are involved. High-precision displacement and acceleration sensors were utilized to conduct tests on the Shanghai maglev line to verify the accuracy of the simulation results. The results indicate that when simplifying the distributed levitation force into a concentrated force model, a frequency ratio can be used to analyze the conditions for resonance between the train and the bridge and to calculate the critical speed of the train; the levitation distribution force of a high-speed maglev vehicle can be simplified into four groups of concentrated forces based on the number of levitation frames to achieve sufficient accuracy, with the dynamic response of the bridge being close to that under distributed loads. [ABSTRACT FROM AUTHOR]

BACKGROUND: Adelphocoris suturalis is a destructive pest that attacks > 270 plants, including cotton, maize, soybean, and fruit trees. Adelphocoris suturalis can cause tremendous crop losses when the density exceeds economic thresholds, but because it can be both phytophagous and zoophytophagous it can serve as a natural enemy of other pests when the density is below the economic threshold. Effective control of its population is beneficial for maximizing yield and profits. RNA interference (RNAi) has potential to be a viable alternative to conventional pesticide‐based pest management, but the lack of efficient double‐stranded RNA (dsRNA) delivery systems and candidate genes are currently limiting factors for field applications. RESULTS: In this study, RNAi of juvenile hormone (JH) receptor components methoprene‐tolerant (Met)/Taiman (Tai) in Adelphocoris suturalis reduced fertility. Based on this reproductive role, we targeted Adelphocoris suturalis Met and Tai for knockdown by coupling nanomaterial‐dsRNA complexes with a transdermal spray delivery system. Within 12 h of adult emergence, females were sprayed with star polycation (SPc)–dsRNA formulations and the RNAi effects were assessed over time. RNAi knockdown efficiencies of 39–58% were observed at 5 days post‐treatment and abnormal ovarian development was apparent by 10 days post‐treatment. CONCLUSION: Our results show that spray‐induced and nanocarrier‐delivered gene silencing (SI‐NDGS) system targeting JH signal genes effectively impaired oviposition, thus developing a novel RNA fertility inhibitor to control Adelphocoris suturalis populations. These results give new perspective on pest management and suggest broad prospects for field applications. © 2024 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

In order to explain the wheel-rail stick-slip vibration phenomenon of alocomotive in a curve, a co-simulation dynamic model taking into account adhesion control was established to reproduce the locomotive wheel-rail curve stick-slip vibration behavior, and the effect of parameters such as creep threshold, descent slope, rail surface condition and track curve radius on the stick-slip vibration behavior was measured by the traction force and the overall dispersion of adhesion coefficient. The results illustrate that the wheel-rail curve stick-slip vibration is caused by the dynamic traction force fluctuation under the adhesion control, and the increase of creep threshold will lead to the decrease of tractive force fluctuation amplitude and the decrease of stick-slip vibration intensity, which will increase the adhesion utilization rate, However, the increase of descent slope, the decrease of track curve radius and wheel-rail friction coefficient have the opposite effect on stick-slip vibration behavior. This phenomenon can be eliminated by improving the rail surface condition, expanding the track curve radius and lowering the locomotive traction force. [ABSTRACT FROM AUTHOR]

To reduce the vehicle-bridge coupled vibration of a new-type maglev vehicle with mid-mounted suspension (MVMS) on a curve and increase its curve-passing speed, the forced guidance device (FGD) for MVMS is designed and the effectiveness of the FGD is proved. Firstly, on the basis of the FGD for HSST (High Speed Surface Transport) maglev vehicle and the geometric relationship between the movable sliders and the cabin as MVMS passes through a curved track, the FGD scheme for MVMS was designed. Secondly, the dynamic models with 5-bogies MVMSs (with and without FGD), control system, 11 flexible bridges, and track irregularities were established. Finally, the vehicle-bridge coupled vibration response of MVMSs on the curved track was analysed. Results show that the accelerations of the bridges, levitation modules, and cabin can be reduced significantly by installing FGD, especially at higher speeds. Compared to the accelerations without FGD, the maximum lateral and vertical accelerations of each bridge midspan can be reduced respectively by 56% and 43% at the speed of 45 km/h, those of the levitation modules can be reduced by 48% and 90%, respectively, and those of the cabin can be reduced by 37% and 53%, respectively. [ABSTRACT FROM AUTHOR]

The malvolio (mvl) gene plays an important role in the transition from nursing to foraging in honeybees (Apis mellifera). Apis cerana cerana (A. c. cerana) is a subspecies of the eastern honeybee, well-known for its pollinator role throughout China. Although A. c. cerana shares many characteristics with A. mellifera, it is unclear whether Acmvl plays a similar role to Ammvl in foraging behavior. In this study, Acmvl expression was quantified during the transition from nursing to foraging in A. c. cerana. Acmvl protein production was also characterized in different tissues in bees from three behavioral groups. Finally, in situ hybridization was used to describe Acmvl expression patterns in forager bee brains. Acmvl expression was low early in life but then showed a major peak, which suggests its role in labor division. Examination of tissue type revealed that Acmvl expression was highest in the thoraxes of nurse bees and the heads of forager bees. In bee brains, Acmvl was selectively expressed in the somata of Kenyon cells in the mushroom bodies, optic lobes and antennal lobes. Taken together, these findings suggest that Acmvl plays a role in the nurse–forager transition of A. c. cerana.