Yusheng Liu

Locusta migratoria manilensis (Meyen) is a highly destructive insect pest worldwide. However, excessive reliance on insecticides has resulted in significant environmental pollution. Biocontrol complexes combine two or more BCAs to address the limitations of individual agents. However, biocontrol complex for locust control has been rarely reported. Here, we propose BioControl 3.0, which integrates Metarhizium anisopliae var. acridum (Driver and Milner) and Carabus smaragdinus (Fischer von Waldheim) for locust control. We evaluated this system through a series of laboratory bioassays and semi-field cage experiments, comparing single-agent applications, sequential combinations (BioControl 2.0), and predator-mediated delivery (BioControl 3.0), and quantified locust mortality and interaction effects between predation and infection We found that M. anisopliae caused >85% mortality of locust nymphs at 1 × 10⁸ conidia/mL (LT₅₀ ≈ 6 days) while exhibiting negligible virulence toward C. smaragdinus. BioControl 2.0 (sequential application) increased mortality compared to single agents. However, this approach revealed a significant negative interaction between predation and infection, which limited the total control efficacy. BioControl 3.0 (predator-vectored fungus) achieved the highest corrected mortality, with predation and infection acting independently and additively (no detectable antagonistic interaction). By leveraging a predatory vector, BioControl 3.0 decouples negative interaction and harnesses dual biotic pressures, offering a cost-effective, environmentally benign alternative to conventional locust control. Our findings provide a blueprint for designing integrated predator-pathogen complexes and optimizing deployment strategies for sustainable management of locust outbreaks.

Cotton stalks (CS) are a potential agricultural biomass resource. We investigated the use of CS as a feed for Proteatia brevitarsis Lewis larvae and the resulting frass (larvae dung-sand) as a fertilizer. Based on a three-factor experiment (decomposition inoculant, fermentation duration, and cattle manure ratio), the optimal parameters for the transformation of CS using P. brevitarsis larvae were determined as 40–50% of cattle manure, the use of VT inoculant and a fermentation duration of 25–30 days. Regarding the products of the transformation, the protein content of the larval body was as high as 52.49%, and the fat content was 11.7%, which is a suitable-quality insect protein source. The organic matter content of larvae dung-sand was 54.8%, and the content of total nitrogen, phosphorus, and potassium (TNPK) was 9.04%, which is twice more than that of the organic fertilizer standard (NY525-2021, Beijing, China, TNPK ≥ 4.0%), and larvae dung-sand has the potential of fertilizer application. Therefore, CS as a feed and fertilizer based on the transformation of P. brevitarsis larvae is feasible, and it is a highly efficient way to promote the utilization of both CS and cattle manure.

Locusts, in particular Locusta migratoria manilensis (Meyen), have been associated with major damages in agriculture, forestry, and animal husbandry in China. At present, L. migratoria manilensis has been largely domesticated, being considered an edible insect in China. Feeding variety is one of the main characteristics of L. migratoria manilensis. It has been demonstrated that microorganisms inhabiting the insect gut impact nutrition, development, defense, and reproduction of the insect host. The aim of the present study was to search for the adaptation mechanism of L. migratoria manilensis feeding on four different food plants (goosegrass, maize leaves, soybean leaves, and pakchoi) and explore changes in the gut bacterial community structure of the insect at the fifth instar nymph stage. Proteobacteria and Firmicutes were the dominant phyla, whereas Kluyvera, Enterobacter, Pseudocitrobacter, Klebsiella, Cronobacter, Citrobacter, Lactococcus, and Weissella were the dominant genera in the gut of L. migratoria manilensis. Principal component analysis and permutational multivariate analysis of variance (PERMANOVA) revealed significant differences in the gut microbiota structure of L. migratoria manilensis fed on different food plants. Moreover, functional prediction analysis revealed that metabolic and cellular processes were the most enriched categories. Within the category of metabolic processes, the most enriched pathways were carbohydrate transport and metabolism; amino acid transport and metabolism; translation, ribosomal structure, and biogenesis; cell wall/membrane/envelope biogenesis; inorganic ion transport and metabolism; and energy production and conversion. Collectively, the present results revealed that the structure of gut bacterial communities in L. migratoria manilensis fed on different food plants is impacted by food plants, which may play an essential part in the adaptation of the host.

Lignocellulose is known to be an abundant source of glucose and xylose for biofuels. Yeasts can convert glucose into bioethanol. However, bioconversion of xylose by yeasts is not very efficient, to say nothing of the presence of both glucose and xylose. Efficient utilization of xylose is one of the critical factors for reducing the cost of biofuel from lignocelluloses. However, few natural microorganisms preferentially convert xylose to ethanol. The simultaneous utilization of both glucose and xylose is the pivotal goal in the production of biofuels. In this paper, we found that 97.3 % of the glucose and 93.8 % of the xylose in our experiments was consumed by black soldier fly (BSF) simultaneously. The content of lipid reached its highest level (34.60 %) when 6 % xylose was added into the standard feed. 200 g of rice straw was pretreated with 1 % KOH, followed by enzymatic hydrolysis for fermentation of ethanol, the residue from this fermentation was then fed to BSF for lipid accumulation. In total, 10.9 g of bioethanol and 4.3 g of biodiesel were obtained. The results of this study suggest that BSF is a very promising organism for use in converting lignocellulose into lipid for biodiesel production.