Obligate phytophagy has independently evolved several times within Acariformes. Obligate phytophagous mites, including the superfamilies Tetranychoidea and Eriophyoidea, predominantly utilize vascular plants as hosts. They typically exhibit a set of adaptations to their host plants, including behavioral and morphological traits. However, as an exception, bryophyte-feeding mites have been reported in Eustigmaeus (Trombidiformes: Stigmaeidae). More than ten species are known to feed on bryophytes, three of which exhibit varying degrees of host specificity. Nevertheless, knowledge of how these mites utilize bryophytes remains limited. Clarifying this may help complement our understanding of the evolution of phytophagy in Acariformes. We focused on the feeding ecology of bryophyte-feeding mites. We examined interspecific variation in feeding behavior and cheliceral morphology across Eustigmaeus species and discussed correlations between these traits and the morphological characteristics of their host plants. Sampling was conducted from western to northeastern Japan and at several locations in Taiwan from March 2021 to October 2025. Feeding behavior of mites on bryophytes was observed using a stereomicroscope. Cheliceral morphology was examined using light and scanning electron microscopy. Evolutionary patterns of cheliceral morphology were reviewed based on a preliminary molecular phylogeny. Bryophyte gametophyte morphology was preliminarily examined. We confirmed that more than ten bryophyte-feeding species extract leaf-cell contents by piercing cell walls with their stylets, consistent with Gerson (1972). In addition, characteristic feeding behaviors were documented. Most observed mites grasped the leaf margin with their appendages while feeding, which may assist feeding by pressing the leaf against the mouthparts. The mites moved their mouthparts to an adjacent new cell each time they consumed an individual cell, which is likely inevitable because bryophyte leaves consist of a single cell layer. Notably, mites in several species moved their mouthparts in a stereotyped manner. These mites positioned their mouthparts near the leaf margin and successively consumed cells while moving linearly toward the leaf center, repeating this sequence while shifting their body position. This linear movement likely minimizes the interval between successive cell feedings, which may be costly, thereby increasing feeding efficiency. Cheliceral morphology, particularly stylet length, differed markedly among species. A preliminary survey implied that stylet length in bryophyte-feeding species correlates with the leaf morphology of their host plants. However, this correlation should be tested with a phylogenetic comparative approach. Reconstruction of a robust phylogeny of Eustigmaeus and further investigation of host plant use are therefore required.