BIOTIC ASSOCIATIONS OF COCKROACHES — ROTH & WILLIS 32I 



at certain stages. MalHs (1954) has stated that crickets prey on other 

 insects as well as on one another. Lheritier (1951) had also observed 

 crickets becoming rare in bakeries in France, having been superseded 

 everywhere by B. orientalis; however, he doubted that Joli vet's hy- 

 pothesis was the correct explanation and suggested that the higher 

 optimum temperature requirements of crickets might be the regulating 

 factor. Lederer (1952) stated that the number of crickets decreased 

 in the aquarium buildings at Frankfurt am Main as the population of 

 American cockroaches increased. 



Platysosteria novae seelandiae was found under the bark of trees in 

 New Zealand devouring bugs (Walker in Shelford, 1909b). 



For years it has been believed that cockroaches feed on bedbugs 

 {Cimex lectularhis L.) and this statement has been repeated in many 

 reference works and articles. Ealand (1915) stated that cockroaches 

 devour bedbugs with avidity. Even today similar statements are to 

 be found in the literature. "In the old sailing ship days, they [cock- 

 roaches] were often welcomed by crews because of the belief that they 

 would eradicate a population of bedbugs. This belief was based on 

 scientific fact, as cockroaches are known as predators of bedbugs" 

 (Monro, 1951). Cockroaches will often "help rid a house of bedbugs 

 by devouring all the little parasites they can capture" (Gaul, 1953). 

 The basis for this belief may have originated with a statement by 

 Webster (1834) who wrote that bedbugs disappeared aboard "H.M. 

 Sloop Chanticleer" when cockroaches made their appearance. New- 

 man (1855) reported the observations of a friend who claimed to 

 have seen a cockroach seize a bedbug in an infested boardinghouse in 

 London. In 1920 Purdy reintroduced cockroaches into a house from 

 which they had been exterminated, in order to control the bedbugs 

 which had become established. According to a popular account by 

 Lillingston (1934) African natives are said to ask sailors for a cock- 

 roach or two to be used to hunt bedbugs. 



In Siberia, Burr (1926, 1939) found Blattella germanica and bed- 

 bugs inhabiting the same room, Mellanby (1939) studied the popula- 

 tions of an animal house in which bedbugs and cockroaches occurred 

 in large numbers ; the bugs apparently were not attacked and their 

 numbers increased greatly over a period of a few weeks (Johnson and 

 Mellanby, 1939). Wille (1920) placed starved B. germanica with 

 bedbugs for 20 days, but the cockroaches failed to attack the bugs. 

 In India, captive adults and nymphs of two species of house cock- 

 roaches would not touch living bedbugs or their eggs (Cornwall, 

 1916). In laboratory experiments Gulati (1930) found that Peri- 



