Termite Gut Spirochetes

There are few habitats on earth in which spirochetes are such prominent members of the microbial community as in the hindgut of termites. This was first documented over a century ago by Joseph Leidy (Leidy, 1874-1881; Leidy, 1877), who was struck by their abundance in hindgut contents of the eastern subterranean termite, Termes (now Reticulitermes) flavipes. In some termites, spirochetes account for up to 50% of all prokaryotes in the hindgut (Paster et al., 1996), and even casual phase contrast microscopic observation of hindgut contents usually reveals about a dozen different morphological types, distinguishable on the bases of cell size, wavelength and amplitude, or pitch (Fig. 1)