Host dietary changes and the hindgut fauna of cockroaches

Peregrine Pauline C. 1974. Host dietary changes and the hindgut fauna of cockroaches. International Journal for Parasitology4: 645–656. The effects of changes in the diet of Periplaneta americana on Hammerschmidtiella diesingi (Nematoda), nematode larvae, Nyctotherus ovalis (Ciliata), Endamoeba blattae (Lobosa), Lophomonas striata (Zooflagellata) and Monocercomonoides orthopterorum (Zooflagellata) have been studied. All species are found in the hindgut of the host and appear to be supported to advantage by slightly different dietary fractions thus enhancing coexistence. Interspecific competition seems to be reduced by both spatial and dietary factors although most species tend to aggregate in a ‘preferred zone’ 30–45 per cent along the length of the hindgut. Under conditions of stress, distribution often expands. Intraspecific competition also appears to be partially controlled by dietary preferences, male, female and larval nematodes responding to differing dietary fractions. Effects on H. diesingi are closely paralleled by those on Thelastoma attenuatum (Nematoda), also parasitic in the hindgut, indicating a very finely balanced system of coexistence. Some of the parameters which may be involved are discussed. Almost all parasites were adversely affected by synthetic diets.