Any studies of insect remains in an attempt to reconstruct past environments. Pollen analysis and molluscan analysis can reveal information on climate, the environment and, sometimes, the activities of man. Insect remains are usually found in the form of the exoskeleton, parts such as the wing-cases of beetles, and they always come from anaerobic deposits such as ditches, wells, pits, and peat bogs; many of the parts of insects that are species-distinctive do not survive in archaeological deposits. They can be separated from the soil sample by flotation. Insects respond more quickly than plants to climatic change, and may therefore assist in the identification of micro-climatic phases. Insects also have habitat preferences, which is helpful in identifying specific environments.