Sunday, December 9, 2001 - 10:24 AM

Will the real Zwickia (Astigmata, Histiostomatidae) please stand up: Biodiversity of mites inhabiting the pitchers of Nepenthes

Norman J. Fashing, Department of Biology, College of William and Mary, Department of Biology, Millington Hall, Williamsburg, VA

In recent years arthropod communities in the fluid-filled pitchers of Nepenthes species have been lauded as excellent subjects for testing community theory, having been used to investigate local and regional variation in food web structure, the meaning of food web patterns, and predation and competition in patchy habitats. Mites are common inhabitants, but our knowledge of them is minimal. Only four species, all in the family Histiostomatidae, have been described: Zwickia guentheri 1915 (N. destillatoria, Sri Lanka), Z. nepenthesiana 1928 (N. ampularia, Singapore), Creutzeria tobaica 1932 (N. tobaica, Java), and C. seychellensis 1979 (N. pervillei, Seychelles). In community studies, some authors arbitrarily assign mites to one of the two existing genera, some refer to mites by family name, and others don't acknowledge their presence. Even when presence is acknowledged, species are lumped together as filter feeders and relegated a minor role. Mite populations are, however, usually quite large; sheer numbers more than compensate for lack of size. An understanding of the roles the various mite species play in Nepenthes communities is therefore essential for an understanding of food webs and communities dynamics. A cursory examination of pitchers from northern Australia, Thailand, Brunei, and Singapore revealed not only species belonging to the existing genera Zwickia and Creutzeria but also species from three additional and as yet undescribed histiostomatid genera. In addition, a sixth genus, Naiadacarus (Acaridae), was observed. The exact number of species is not yet determined; 15 is a conservative estimate. Some species are generalists inhabiting several Nepenthes species; others are confined to a single species. I examined only six species of Nepenthes, but to date over 80 have been described. Numerous undescribed species of Nepenthes-inhabiting mites undoubtedly exist.

Species 1: Acari Histiostomatidae Zwickia
Species 2: Acari Histiostomatidae Creutzeria
Species 3: Acari Acaridae Naiadacarus
Keywords: Pitcher plant, Nepenthaceae

The ESA 2001 Annual Meeting - 2001: An Entomological Odyssey of ESA