Pillotinas and hollandinas: distribution and behaviour of large spirochaetes symbiotic in termites.

Abstract

Pillotina spirochaetes have been observed in the hindguts of wood-eating cockroaches (Cryptocercus punctulatus), and in 25 out of 28 species of termites examined. They were especially abundant in 21 species of dry wood termites of the family Kalotermitidae, from Europe, North America and Australia. These included many species of Kalotermes and one or a few of the following: Glyptotermes, Bifidotermes, Neotermes, Ceratokalotermes, Paraneotermes, Cryptotermes, Porotermes, Marginitermes, Pterotermes, Zootermopsis, Reticulitermes, Coptotermes, Heterotermes, and nasutitermitids. Identifications of pillotinas were made on the basis of large size (0.5--2 micromtere in diameter, 50 to greater than 100 micrometers in length) and wave pattern; these were verified by electron microscopy in K. schwarzi, Pterotermes occidentis and others. Pillotinas were also present in all species of subterranean termites (Family Rhinotermitidae) examined, and in the most primitive Australian termite, Mastotermes darwiniensis (Family Mastotermitidae). They were not observed in damp wood termites (Family Hodotermidiae). Pillotinas are invariably associated with a rich, complex xylophagous microbial community composed primarily of motile prokaryotes, and hypermastigote and polymastigote flagellates. Some have been previously described by those primarily concerned with termite hindgut protozoa. Observations were made on their modes of behaviour, division, and microbial associates. A new genus of spirochaetes, Hollandina, is also described. It is distinguished from Pillotina by a smaller size and several ultrastructural features, but is otherwise closely related taxonomically. Evidence is provided to support Hollande and Gharagozlou's (1967) concept that the pillotinas and hollandinas deserve the taxonomic status of 'family' and that they should be classified with the cristispire siprochaetes a-cording to the scheme developed by Hovind-Hougen (1976). Spirochaetes are treated as a Phylum of the Kingdom Monera (Prokaryota) in the five kingdom system of Whittaker (1969).