Study of dispersal and diversity of eriophyoid mites (Acari: Eriophyoidea)

Eriophyoid mites represent a major, agriculturally important group of mites. The knowledge of dispersal biology and species diversity of eriophyoids is very limited, because their tiny body size makes observation and study difficult.;The current method of using sticky glass slides or plates to sample airborne eriophyoids is inefficient and inappropriate. A new method using water pan traps and vacuum-filtration proved far superior to the previous method.;A three year investigation using the water pan sampling method resulted in a total of 8,131 airborne eriophyoid specimens, 60.6% of which were collected from the roof of a 40m high building. Airborne eriophyoids were collected in each month of the year. While a significant peak period of aerial dispersal for all eriophyoids occurred in June--July, the yearly aerial dispersal profile varied with species and location. Their airborne activities had an evident diurnal pattern with a peak in mid afternoon. Meteorological factors, except for wind, did not seem to have a significant effect on daily airborne catches of eriophyoids in summer.;The airborne collection contained 598 species of eriophyoids in 66 genera, most new to science. Their taxonomic distribution pattern closely matched that of described species. But only about 30 species made up the vast majority of the total specimen abundance of the collection. The species composition of an airborne collection varied with year and location.;A total of 171 arthropods were collected in 249 kg of snow from 10 major snowfalls. The fauna included 89 eriophyoid specimens and 75 mites in other groups, both in diverse taxa. Presence of mites in snow further indicated their great potential for aerial dispersal, and might imply their potential for long distance dispersal.;Only 24 eriophyoid specimens were recovered from about 35,000 insects from Malaise traps, so phoresy occurs to a very limited extent in eriophyoids.;The total of 620 collected airborne and snowborne species greatly increased the size of known faunas for the investigated region (74 species in West Virginia) and the U.S. (653). Still, the accumulation curves of new species vs. collection size indicate that the total diversity of the Eriophyoidea within the study area is higher than obtained