Examination of Frozen, Hydrated Mites Using Low Temperature Field Emission Scanning Electron Microscopy

Abstract Mites, the second largest arthropod group after insects, occupy every conceivable terrestrial and aquatic habitat in our environment. They feed on plants, infest food products such as meat, cheese and grains, parasitize invertebrates and vertebrates, and transmit fungal, bacterial, rickettsial and viral diseases. Estimates indicate that as many as 1,000,000 species of mites may exist; however, partly because of their microscopic size, only about 40,000 species have been described and classified. During the last 30 years, researchers have increasingly utilized the greater magnification and depth of field available in a conventional scanning electron microscope (SEM) to supplement descriptions of mites that were historically based on light microscopic observations. In addition, this technique provided a better understanding of the relative positions and functionality of organs and improved attempts to elucidate their biology. However, before mites can be imaged with a conventional SEM, they are typically chemically fixed, dehydrated and/or thoroughly dried.