Physicochemical characteristics of stored products affect host preference and biology of Acarus siro (Acari: Acaridae)

Flour mite Acarus siro (Acari: Acaridae) is an injurious postharvest pest of various stored products. The objective of this study was to investigate the effect of physicochemical characteristics of stored products on A. siro. In this research, the host preference and biology of the mite were studied in three varieties of rice, two varieties of sticky rice, and three different types of cheese. We considered the differences in grain granulometry (whole, broken, and flour) as variation in physical characteristics of the stored products, and proportions of basic nutritional content as variation in chemical characteristics. The results indicated that when offered to grain with different granulometry, A. siro selected broken grain as their host and oviposition site. Furthermore, the mite’s host preferences were also influenced by the nutritional content variation of the stored products. In biology experiments, the total development of A. siro lasted from۱۶.۷۸ ± ۰.۱۳ to ۲۰.۶۰ ± ۰.۵۱days and its fecundity ranged from ۱۷.۶۵ ± ۱.۷۵ to ۵۳.۰۵ ± ۰.۰۹ eggs per female. However, the results suggested that faster development and higher fecundity of the mite were generally found in a diet(s) with higher protein, fat, and water content. Additionally, we demonstrated that A. siro is better adapted to flour products, indicating the influence of particle size on the development and reproduction of the mite. Therefore, physicochemical characteristics of the stored products strongly affected the host selection and biology of A. siro, which in turn determines the degree of product susceptibility upon mite infestation.

Keywords:

postharvest pest , rice , sticky rice , cheese , grain granulometry , nutritional content