Impact of Nutritional Supplements on the Fitness of the Parasitoid Binodoxys communis (Gahan).

Alterative nutritional foods consumed by adult parasitoids play an important role in their fitness and ability to control pests because of food scarcity in many crops. While adult parasitoids feed on various sugars, they vary in their nutritional value for parasitoids. We assessed the effects of seven sugars (fructose, glucose, sucrose, trehalose, maltose, melezitose, and sorbitol) on the longevity, parasitism ability, parasitism behavior, and flight ability of B. communis, an important parasitoid of cotton aphids. We found that access to glucose, sucrose, or fructose, increased B. communis adult longevity more than the other sugars offered. All sugars except trehalose increased the parasitism rate to more than 50% compared to the starved control (only provided with water). We then compared parasitoid behaviors of wasps fed glucose, sucrose, or fructose to that of the starved control (with access only to water) and found that those fed B. communis spent more time either examining or attacking aphids than parasitoids in the control group, which spent more time walking or resting. Also, consumption of glucose, sucrose, or fructose also significantly improved the flight ability (the total flight distance, flight time, and average flight speed) of B. communis.

Evolution and Influencing Mechanisms of the Yili Loess Mechanical Properties under Combined Wetting-Drying and Freeze-Thaw Cycling.

Landslides frequently occur in the loess-rich Yili region of Xinjiang, China, due to the combined effects of wetting-drying and freeze-thaw (WD-FT) cycles, which cause changes in the soil/loess internal structure and shear strength. This paper explores the combined effect of WD-FT cycles on the shear strength evolution of Yili loess through cyclic and triaxial shear tests. The micromechanism of the effect of WD-FT cycles on the loess properties is studied through scanning electron microscopy tests. Finally, the gray correlation analysis method assesses the correlation between relevant macro and micro parameters. The results show that: (1) With the increase in WD-FT cycles, the cohesion of loess decreases first and then gradually stabilizes, while the internal friction angle first grows and then drops before stabilizing. This indicates that the WD-FT cycles cause different degrees of decline in the soil's internal friction angle and cohesion. (2) As the number of WD-FT cycles increases, the average abundance and directional probability entropy fluctuate slightly, gradually decreasing and stabilizing. In contrast, the particle size dimensionality gradually decreases and stabilizes, and the pore area ratio first increases and then gradually stabilizes. (3) Six microstructural parameters (average diameter, average abundance, particle size dimensionality, directional probability entropy, particle roundness, and pore area) are selected for correlation analysis with the shear strength index of loess. The results show that the particle size dimensionality closely correlates with macroscopic internal friction angle under coupled cycling, while the pore area closely correlates with macroscopic cohesion. These findings are instrumental in preventing and controlling loess landslides caused by WD-FT cycles in the Yili region of Xinjiang, China, and similar loess-rich regions.