BIOTIC ASSOCIATIONS OF COCKROACHES — ROTH & WILLIS 3 



are commensals or secondary parasites of cockroaches, but some of 

 these names are synonyms. La Rivers (1949) extended this Hst with 

 13 additional species. Chitwood (1932) recognized 24 species of 

 nematodes which are primary parasites (probably commensals) of 

 blattids. Steinhaus (1946) gave many instances of biological rela- 

 tionships between cockroaches and bacteria, fungi, and yeasts, but the 

 cockroaches were not discussed as an entity and the information is 

 scattered throughout the book. 



In surveying the literature on this subject we have collected a far 

 more extensive list of animals and plants associated with cockroaches 

 than one might have expected from an examination of any one of the 

 previous papers on this subject. In our review of the medically im- 

 portant organisms associated with the Blattaria, we pointed out that 

 in addition to many experimental associations cockroaches have been 

 found to harbor, naturally, 4 strains of poliomyelitis virus, about 

 40 species of pathogenic bacteria, the eggs of 7 species of pathogenic 

 helminths, and to serve as intermediate hosts of 12 other species of 

 helminths pathogenic for vertebrates; cockroaches have also been 

 found to carry, on occasion, 3 species of Protozoa that are pathogenic 

 to man and 2 species of fungi which are sometimes found associated 

 with pathological conditions. 



In addition to the above organisms of medical importance, we have 

 compiled records of other organisms, nonpathogenic to vertebrates, 

 which are naturally associated in some way with cockroaches. None 

 of the following numbers can be considered absolute because some 

 names may be synonyms. However, we believe that these figures are 

 very close to the actual numbers of species that have been isolated 

 because we have attempted to refer all obvious synonyms to the 

 currently accepted name for each organism. On this basis there are 

 about 45 species of bacteria, 40 fungi, 6 yeasts, 90 Protozoa, and 

 45 helminths that have been found associated naturally with cock- 

 roaches. Of the arthropods there are about 2 species of scorpions, 

 4 spiders, 15 mites, 4 centipedes, and 90 insects. Of vertebrates there 

 are 4 species of fish, 16 amphibians, 12 reptiles, 20 birds, and 27 mam- 

 mals. Besides these there are many records of experimental associa- 

 tions that have been contrived in the laboratory. 



Some idea of the increase in our knowledge of the biotic associations 

 of cockroaches, during the last 70 years, may be gathered from a 

 comparison of the above figures with those of Miall and Denny 

 (1886) who presented "... a long list of parasites which infest the 

 Cockroach." This list included 2 bacteria, 6 Protozoa (some of the 

 names are synonyms), 7 nematodes (some of these names are also 



