The mite collection comprises more than 13,000 specimens on microscope slides. The Bader water mite collection is accepted as one of the most significant ones of this group of animals worldwide. Other collections go back to Schweizer, Schwoerbel, Sepasgozarian, Walter and Daday.
Mites belong to the arthropods and are related to spiders and scorpions. They are very small, live in water or on land or exist as parasites in and on animals or plants. Mites are a highly diverse group of animals. The parasitic species in particular can in some cases have very strange appearances.
Due to their small size, mites do not have a great deal of exhibition value. From a scientific perspective, however, they are extremely interesting.
For more than half a century, Carl Bader worked as a freelancer for the Natural History Museum Basel, researching on water mites. This long-term contact allowed many significant reference specimens and collections to come together: material from the Swiss National Park, from Swiss waterbodies (Walter collection) and extensive material from Iran.
The significantly smaller number of land-based mites is primarily represented by the Schweizer collection. With the exception of feather mites from Switzerland and Saudi Arabia, collected by Willi Büttiker, the collection contains barely any parasitic mites.