Host-Dependent Variation in Tetranychus urticae Fitness and Microbiota Composition Across Strawberry Cultivars

Tetranychus urticae, commonly known as the two-spotted spider mite, is a highly adaptable and polyphagous arthropod in the family Tetranychidae, capable of feeding on over 1200 plant species, including strawberries (Fragaria × ananassa Duch.). The fitness and microbiota of herbivorous arthropods can vary significantly across different plant species and cultivars. In this study, we investigated the fecundity, longevity, growth rate, and microbiota composition of T. urticae reared on seven Chinese strawberry cultivars: Hongyan (HY), Yuexiu (YX), Tianshi (TS), Ningyu (NY), Xuetu (XT), Zhangjj (ZJ), and Xuelixiang (XLX). Our findings revealed significant differences among cultivars: mites reared on the XT cultivar exhibited the highest fecundity (166.56 ± 7.82 eggs), while those on XLX had the shortest pre-adult period (7.71 ± 0.13 days). Longevity was significantly extended in mites reared on XLX, XT, and NY cultivars (25.95-26.83 days). Microbiota analysis via 16S rRNA sequencing showed that Proteobacteria dominated (>89.96% abundance) across all mite groups, with Wolbachia as the predominant symbiont (89.58-99.19%). Male mites exhibited higher bacterial diversity (Shannon and Chao1 indices) than females, though Wolbachia abundance did not differ significantly between sexes or cultivars. Functional predictions highlighted roles of microbiota in biosynthesis, detoxification, and energy metabolism. These findings underscore the influence of host plant variety on T. urticae fitness and microbiota composition, suggesting potential strategies for breeding resistant strawberry cultivars and leveraging microbial interactions for pest management.