LEAF DOMATIA AND THE DISTRIBUTION AND ABUNDANCE OF FOLIAR MITES IN BROADLEAF DECIDUOUS FOREST IN WISCONSIN

Leaf domatia occur frequently in vein axils on the leaf undersurface o f many woody Dicotyledonae in the broadleaf deciduous forests of the n orthern hemisphere. These structures are often used by mites for shelt er and as sites for egg laying. Taxa of predatory and fungivorous mite s and sometimes of herbivorous mites were associated with the domatia of six species of trees or woody vines (Quercus velutina, SZ. rubra, A cer saccharum, Prunus virginiana, P. serotina and Vitis riparia) exami ned near LaValle in S-central Wisconsin. Comparisons of mite frequency and abundance in different leaf microhabitats (in domatia, in major v ein axils without domatia, along the midrib, and on the leaf lamina) s howed that mites respond strongly to leaf architectural features, espe cially domatia. Further, mite evidence was more frequent or mites more abundant on leaves of species with domatia in four of five paired-spe cies comparisons. The abundance of potentially beneficial mites, prima rily Metapronematus leucohippeus (Tydeidae) and Typhlodromus nr. pomi (Phytoseiidae) was significantly greater and the overall ratio of bene ficial to herbivorous mites was greater on leaves of species with doma tia. Leaf domatia are important shelters for potential plant mutualist s and alter the distribution and abundance of foliar mites in the cano py of temperate broadleaf deciduous forest.