Bryobia mites are among the largest spider mites. The adult is visible to the naked eye. Mites of this genus are mainly distinguished by the arrangement of the setae on their bodies. In general, these mites are red in color with whitish setae and long legs with hooked claws.
Bryobia mites feed on plants. They puncture the plant tissues with their sucking mouthparts. They are often found on leaves, but they also live on branches and twigs.
The life history is variable across species. Typically, it takes about a month for a mite to develop from egg and larva to adult. This depends on environmental conditions such as temperature and humidity. Some species overwinter in the egg stage. Some species have a single generation per year, while others have several. The eggs are laid singly or in clutches, and some mites may cover the eggs with dust or other matter. Unlike some other spider mites, bryobia mites do not spin webs.
Some Bryobia reproduce sexually, but many, probably most, species are asexual. Their populations are all female, and individuals reproduce by thelytoky, a form of parthenogenesis. They emerge from unfertilized eggs. Phylogenetic analysis shows that the asexual species in the genus are not a monophyletic group; it is likely that asexual reproduction evolved several times instead of just once in some common ancestor. The asexual species have a high level of genetic diversity considering that they are clones; this may have arisen through hybridization and mutation. In at least two species, namely Bryobia kissophila and B. praetiosa, asexuality is caused by the parasitic bacterium Wolbachia. This bacterium causes functional apomixis in the mites, so that a female produces only offspring that are identical to her. It is possible that Wolbachia could influence the reproductive processes of most bryobia mite species.