Physiological reprogramming during cold acclimation in the predatory mite Neoseiulus bicaudus.

Neoseiulus bicaudus Wainstein (Acari: Phytoseiidae) serves as an effective biological control agent for managing spider mites and small pests. The cold acclimation of predatory mites significantly influences their distribution patterns and survival at low temperatures. In this study, we examined the effects of cold acclimation on the cold tolerance of N. bicaudus and investigated the physiological responses associated with different durations of cold acclimation (6-hour: 3 °C for 6 h; 24-hour: 3 °C for 24 h; 7-day: 9 °C for 7 day) using metabolomics. Cold acclimation significantly enhanced the low-temperature survival capability of N. bicaudus. Moreover, this process elicited a range of physiological and metabolic adaptations in predatory mites. Specifically, a 7-day cold acclimation period yielded the most pronounced changes. The cold acclimation response of 24-hour and 7-day was attributed to the reprogramming of metabolites involved in sugar metabolism (e.g., D-fructose and maltose), amino acid metabolism (e.g., DL-phenylalanine and L-serine), and lipid metabolism (e.g., octanoate, (9Z)-hexadecenoic acid, cholesterol, glycerophospholipids, lysophospholipids). Additionally, 24-hour acclimation at 3 °C enhanced the activities of antioxidant enzymes such as superoxide dismutase and peroxidase, along with increased levels of antioxidants like zeaxanthin, coenzyme Q10, and retinol. After 7 days of cold acclimation, the levels of various antioxidants, including glutathione, zeaxanthin, γ-tocopherol, retinol, xanthine, and carnosine, were markedly elevated. Collectively, these physiological adaptations are strongly correlated with the maintenance of homeostasis in N. bicaudus under low-temperature stress, suggesting they collectively contribute to its enhanced survival capacity.