Xingfu Jiang

Symbiotic bacteria contribute to insect physiology and environmental adaptation, yet their dynamics and potential functions in the major migratory pest Loxostege sticticalis remain poorly understood. We characterized bacterial community composition, diversity, and predicted functional potential across developmental stages, tissues and frass samples, and environmental conditions. In laboratory-reared insects, Enterococcus and Staphylococcus predominated from the second to fifth instars, whose predicted functions emphasized carbohydrate and nucleotide metabolism. Adults were instead dominated by Pseudoalteromonas and Asaia, with predicted profiles showing greater representation of lipid and amino acid metabolism and transport and catabolism. First-instar larvae exhibited an adult-like community structure. Among sample types, Enterococcus predominated in the midgut, whereas Staphylococcus was overrepresented in the epidermis and frass. Epidermal and frass communities emphasized cellular processes and genetic information processing, whereas midgut and other internal tissue communities showed greater predicted potential for membrane transport and metabolism. Wild-caught larvae harbored distinct communities consistently enriched in Stenotrophomonas and Ralstonia, with predicted profiles shifting toward carbohydrate, amino acid, and lipid metabolism and environmental adaptation in later instars. Overall, these findings demonstrate that the symbiotic bacterial communities of L. sticticalis vary markedly with development, tissue niche, and environment, providing a basis for further studies of host–microbe interactions.

The two-spotted spider mite, Tetranychus urticae Koch, is a major agricultural pest with a rapid propensity for developing acaricide resistance. Bifenazate targets mitochondrial cytochrome b (CYTB). While the G126S mutation is associated with resistance, its independent role remains unclear, as it often occurs with other SNPs. This study explores the molecular basis of bifenazate resistance in a Russian laboratory strain derived from a St. Petersburg greenhouse population. Disruptive selection with increasing bifenazate concentrations generated resistant and susceptible isofemale lines. AlphaFold2 structural modeling of CYTB indicated that G126S causes a steric clash, leading to conformational destabilization, whereas other reported mutations primarily affect the ligand-binding pocket. Oxford Nanopore sequencing revealed a low initial frequency of the G126S allele (cytb fragment. We report the first identification of the G126S mutation in a Russian T. urticae population and demonstrate rapid fixation under bifenazate selection. Within this genetic background, G126S alone appears sufficient to confer high-level resistance, emphasizing the population-specific nature of resistance evolution and the critical need for local monitoring.

Cross-generational plasticity, defined as non-genetic parental influences on offspring life history traits, represents a critical but underexplored mechanism in insects’ life-history adaptation. Current study was conducted to investigate how parental temperature (TP), offspring developmental temperature (TD), and offspring adult temperature (TA) interact to influence the offsprings performance in Mythimna separata. Offsprings from low-TP parents showed slower development at low TD, longer pre-oviposition periods, and the highest (331.92±8.04 mg) pupal mass compared with offsprings from high-TP parents 261.11±9.6 mg with significant differences (P≤.0.001). Furthermore, females whose parents were reared at low temperature were heavier, more fecund and had weaker flight abilities than females whose parents were reared at high temperature indicating a trade-off between reproductive investment and dispersal ability with significant differences (P≤0.001). In contrast, progeny from warm parental environments developed more rapidly, matured earlier, and exhibited stronger flight performance with less fecundity. Low TA consistently constrained fecundity and weaker flight ability across treatments, highlighting the importance of within-generation effects of low temperature. Overall, findings revealed that cooler environments favor phenotypes with delayed development (64.98 ± 6.58 Days), higher fecundity (556.96 ± 23.58), and weaker dispersal capacity, whereas warmer conditions promote faster development (30.88 ± 5.36 days), enhanced dispersal, but lower (410 ± 31.56 eggs) reproductive output with significant differences (P≤0.002). These results suggest that cross-generational plasticity mediates adaptive trade-offs between reproduction and dispersal, thereby determining population dynamics and migratory potential. By aligning offspring traits to the thermal conditions experienced by parents, cross-generational temperature effects can strengthen pest survival in changing climates. Keywords: Cross generational effects, offspring, temperature, life history traits, flight performance.

BACKGROUND: Tea is a crucial industrial beverage and cash crop that has been facing the dire effects of monoculture cropping (MCC), the accretion of pesticide residues and pest resurgence aggravated by climate change, and the disproportionate use of chemical inputs. Legumes are the most prominent cover crops that can modulate tea quality and attract beneficial arthropods, in tea agroecosystems. This study examined the synergistic impacts of leguminous cover cropping (LCC) with soybean (S) and cowpea (C) on tea quality attributes and the population dynamics of key tea pests. RESULTS: The results vividly demonstrated that, compared to MCC, LCC‐S;C significantly enhanced the foliar concentrations of key bioactive compounds such as caffeine and theanine. However, LCC‐S;C significantly diminished the foliar concentrations of soluble nutrients, including soluble sugars, proteins, free fatty acids, essential amino acids, and bioactive compounds like total polyphenols, and monomer catechins. Notably, LCC‐S;C enriched the foliar concentrations of catechin (epigallocatechin, EGC) and the essential amino acid isoleucine (Ile). Additionally, LCC‐S; C significantly reduced the population abundances of three key tea pests ( Empoasca onukii , Ricania speculum , and Trialeurodes vaporariorum ), thereby aiding in natural pest control. CONCLUSION: The findings highlight that LCC presents a viable alternative to MCC, improving tea quality, while simultaneously reducing the population abundances of key insect pests, and supporting the development of environmentally benign and economically sustainable cultivation practices in tea plantations. © 2026 Society of Chemical Industry.

BACKGROUND: The beet webworm, Loxostege sticticalis , a globally notorious agricultural pest enters diapause as mature larvae to overwinter in the northern temperate zone. The moth develops normally at 16L: 8D and 22 ± 1 °C, and enters diapause at 22 ± 1 °C and 12L:12D. While juvenile hormone (JH) regulates larval diapause in this insect species, the role of photoperiod‐20‐hydroxyecdysone (20E) Axis remains enigmatic. RESULTS: Photoperiod‐driven diapause progression is orchestrated through synchronized changes in 20E titers and expression of PTTH, EcR, and USP . Under short‐day conditions, mature larvae exhibited 20E peaks followed by sustained lower levels (≈50 ng/mg) during diapause, PTTH expression was suppressed at diapause while EcR/USP co‐downregulation in maintained diapause. Diapause terminating individuals showed pre‐activation of PTTH/EcR/USP transcription before 20E resurgence. However, non‐diapause larvae under long‐day photoperiod, steadily rising 20E titer were mirrored by progressive PTTH/EcR/USP upregulation. Functional validation revealed that microinjection of 20E agonist‐‐tebufenozide at early fifth‐instar significantly prolonged larval development by 5.8 days but accelerated pupation by 11.9 days. Conversely, RNAi‐mediated knockdown of PTTH, EcR, or USP dramatically shortened the fifth‐instar duration but led to a significant 9.70 days extension of the mature larval phase. CONCLUSION: Our results establish a causal chain wherein photoperiod disrupts 20E biosynthesis via PTTH suppression, leading to EcR/USP silencing that sustains diapause. Pharmacological and genetic interventions demonstrate that the PTTH‐20E‐EcR/USP axis governs developmental transitions during both diapause and non‐diapause trajectories. © 2025 Society of Chemical Industry.

BACKGROUND: Male insect sex pheromones play a critical role in reproductive behavior by synchronizing female receptivity and deterring rivals, thereby increasing reproductive success. As a major worldwide migratory pest, the beet webworm, Loxostege sticticalis L., has been the subject of sex pheromone research – though previous efforts have focused exclusively on female‐produced signals. The male‐specific sex pheromone and its functions remain largely uncharacterized. This study therefore aimed to identify the male‐specific pheromones in this species and elucidate their behavioral effects on conspecifics. RESULTS: Gas chromatography–mass spectrometry (GC–MS) analysis of crude extracts from abdominal tips of female and male moths identified a total of 15 compounds. Thirteen compounds were detected in both sexes, whereas ( E )‐ocimene and ( Z )‐11‐hexadecen‐1‐yl acetate (Z11‐16:Ac) were male‐specific, with ( E )‐ocimene produced at an eight‐fold higher level than Z11‐16:Ac. Both compounds elicited significant electrophysiological responses in antennae of both sexes. In behavioral assays, the two components used separately or as a binary blend increased calling behavior in 3‐ and 4‐day‐old females, but not in older females. In males, the binary mixture reduced courtship persistence and mating success in younger males (3–5 days old); this effect diminished in 6‐day‐old males. CONCLUSION: The dual function of these male pheromones – enhancing female receptivity while suppressing conspecific male competition – represents an adaptive strategy that facilitates rapid population establishment after migration. These findings provide critical insights into chemical communication in the beet webworm and establish a mechanistic foundation for developing novel pest management strategies targeting reproductive behavior. © 2025 Society of Chemical Industry.

The integration of leguminous cover cropping systems (LCR), particularly soybean (LC-S) and cowpea (LC-C), into tea agroecosystem provides a sustainable strategy to enhance soil ecosystem services by promoting beneficial soil microbial communities through the modulation of the rhizosphere microbiome in the tea rhizosphere soil. This study employs 16S rRNA gene sequencing to assess how these leguminous cover crops, when incorporated as green manure within the tea row spaces, influence the microbial community diversity in the rhizosphere soil of tea plants. Compared to conventional monoculture tea plantations (CK), the introduction of LC-S and LC-C significantly reshape the microbial communities in the tea rhizosphere soil. They promote the abundance of copiotrophic and specialized taxa such as Proteobacteria, Actinobacteria, and Mycobacterium, which are crucial for nutrient cycling and organic matter decomposition. Additionally, LC-S and LC-C enrich beneficial microbes including Chloroflexi, Bradyrhizobium, Acidothermus, and Cyanobacteria, supporting processes like nitrogen fixation and pathogen suppression. The metagenomic analysis confirms that leguminous cover crops consistently increase bacterial diversity and enrich beneficial phyla vital for soil nutrient dynamics, organic matter breakdown, and environmental stress resilience. Furthermore, microbial genera linked to nitrogen mobilization and complex organic matter degradation are promoted, underpinning the synthesis of nitrogenous compounds (such as theanine, amino acids), polyphenolic secondary metabolites (like flavonoids), and volatile organic compounds essential for tea quality. Functional pathway analyses revealed that LC-S enhances degradation pathways involved in carbohydrate and aromatic compound metabolism, augmenting precursors for key bioactive constituents such as theanine and catechins. Conversely, LC-C favors glycan biosynthesis and degradation pathways, likely improving root–microbe interactions and micronutrient uptake, both critical for polyphenol biosynthesis. Collectively, these microbiome-driven changes improve tea’s sensory qualities, including flavor, aroma, and antioxidant capacity, by enriching bioactive compounds. This microbiome-mediated agro-ecological approach offers a sustainable alternative to conventional monoculture, enhancing soil functionality, ecological resilience, and the economic viability of tea production systems.

Migratory insects employ various adaptive strategies during alterations in the maternal environment, such as maternal rearing (Isolation, moderate, or crowding) which significantly affect their offspring's survival, development, reproduction, and onset of migration. While previous studies have mainly concentrated on the impact of varying temperature conditions on insect populations, the effects of changes in maternal rearing density on their progeny have been given relatively less attention. The current study emphasizes the impact of maternal rearing density on the offspring's life history traits in the Mythimna separata. Eggs were collected from laboratory stock and newly hatched larvae from maternal design split into three density regimes and reared at densities of low-density (LD) 1 larva, moderate density (MD) 10 larva, and high density (HD) 20 Larva per 800-ml jar with the diameter of 10cm. For initiation of the next generation, 400 females were selected from the maternal design and kept per combination for offspring larval density, eggs laid by mothers were collected and offspring were again divided into three groups and exposed to (LD), (MD), and (HD). Results demonstrated that the development time of offspring was shortened (31.62±1.14 days) after maternal high-density rearing with a significant difference, offspring’s pupal mass significantly decreased (211±7.58 mg) at stressed conditions. Low-density reared mothers laid fewer eggs (480±28.63) as compared to crowded mothers (718±45.52) eggs with significant differences. Offsprings whose mothers were raised at moderate density displayed the greatest, and offspring raised in isolation had the poorest flight capability relative to high density. Maternal larval density had a significant impact on the offspring pre-oviposition period (POP), offspring with longer POP usually showed more significant flight potential, also POP of all offspring density regimes had an essential and positive correlation with total flight distance, LD (P=0.001; R2=0.99), MD (P=0.002; R2=0.99) and HD offspring’s (P=0.001; R2=0.98). However, moderate and high-density offspring negatively correlated with total flight duration (R2-0.43) and (R2-0.48), respectively. In conclusion, the maternal rearing environment imposes phenotypic changes on offspring life history traits, and flight-induced changes in maternal egg provisioning had direct consequences for offspring growth and survival across each life stage from egg to adulthood. Keywords: Maternal effect, density, offspring development, reproductive plasticity, flight performance

The beet webworm Loxostege sticticalis has caused significant economic losses to the production of agriculture and animal husbandry in China. Preference testing of larva feeding and adult oviposition and flight capability tests were carried out on five host plants: soybean, pigweed, pea, broad bean, and alfalfa. An experimental population life table and population growth trends over the subsequent 200 days were constructed. The test results show that the larvae showed no significant preference among different plants. However, adults lay more eggs on soybeans. The pests failed to complete a generation when fed on broad beans and alfalfas. When fed on pigweed, they showed the shortest larvae development period, the heaviest pupal weight, the longest adult longevity, and the largest egg-laying amount. The net reproductive rate (R₀), intrinsic rate of increase (r), finite rate of increase (λ), and simulated population growth trend of the pests fed on pigweed show the highest values, and those fed on peas showed the lowest values. The total flight distance and flight time of adults fed on pigweed and soybeans were significantly greater compared to those fed on peas. In summary, beet webworms fed on pigweed showed the fastest development and reproduction, the largest population, and the strongest flight capability.

BACKGROUND: Temperature is an important determinant of developmental and reproductive rates in insects. Here, we investigated the physiological responses of adult beet webworm, Loxostege sticticalis L. (Lepidoptera: Crambidae), to three temperatures (16, 23 and 30 °C) focusing on trehalose metabolism.RESULTS: Exposure of moths to 30 °C accelerated eclosion and ovarian development, but shortened the oviposition period and adult longevity, whereas exposure to 16 °C had opposite effects. Transcriptome analysis revealed that vitellogenin (VG) and vitellogenin receptor (VR) genes were up‐regulated at 30 °C, as were numerous genes related to energy metabolism, including those involved in the insulin signaling pathway, the tricarboxylic acid (TCA) cycle, and glycolysis. Expression of the trehalose transporter gene TRET1 was also induced at high temperature, primarily in the ovaries, where trehalose content increased, accompanied by lipid degradation in the fat body. Treatment with the trehalase inhibitor validamycin A reduced female fecundity and longevity at 23 °C, but enhanced the expression of genes related to stress resistance and reproduction, mimicking the effect of high temperature.CONCLUSION: Besides their practical utility for predicting the oviposition behavior and geographic distribution of L. sticticalis in the field, these results elucidate the various physiological roles of trehalose in L. sticticalis during exposure of moths to high temperature and may provide insights into the relationship between stress resistance and reproduction in insects more generally. © 2024 Society of Chemical Industry.