We generated 38-bp Illumina reads from single messenger RNA libraries from three diverse developmental stages of the two-spotted spider mite to capture small RNA diversity across development. Adult, nymphal+larvae and embryonic stages were separated using sieves of various pore sizes, and mites of various developmental stages were carefully selected for small RNA library preparation. Samples were a mix of males and females to capture male and female patterns of small RNA composition and were reared on beans (Phaseolus vulgaris cv California Red Kidney). Small RNA reads were used for miRNA prediction, piRNA discovery, and for quantitation of small RNA-generating loci (i.e. expression across development). Overall design: Examination of small RNA from spider mites of adult, embryonic and pooled larval/nymphal developmental stages.