BIOTIC ASSOCIATIONS OF COCKROACHES — ROTH & WILLIS 3I9 



Davis (in Rehn and Hebard, 1914a) stated that "At Punta Gorda 

 [Florida] there was a vacant house at the end of the town frequented 

 at night by a Nanny and Billy goat, and on warm evenings many Peri- 

 planeta australasiae would run about on the piazza floor and on the 

 sides of the house. They were seen feeding on the excrement of the 

 goats and were no doubt to a great degree dependent upon them." 

 This is another example of a coprophagous insect that has taken 

 advantage of a particular situation favorable to its survival. Similar 

 associations exist in which many of the domiciliary cockroaches feed 

 on the feces of man and domestic and other animals (Roth and Willis, 

 1957a). 



XVI. COCKROACHES AS PREDATORS 

 INTERSPECIES PREDATION 



Tepper (1893) made the broad statement that the majority of 

 Australian and Polynesian cockroaches appear to be wholly carnivo- 

 rous, eating other insects, eggs, and larvae. He stated that, because of 

 their voracity and cannibalistic tendencies, the carnivorous species 

 lead more or less solitary lives so that one rarely meets several in 

 close proximity; they are never very numerous at any time because 

 the stronger devour the weaker in the absence of other prey. Tepper 

 stated that Australian species of Ischnoptera hunt for their prey 

 among the foliage of shrubs, and that Australian species of Cutilia 

 [ = Drymaplaneta, Hebard (1943)] run about actively on the surface, 

 or ascend shrubs and trees in quest of living insects and therefore are 

 highly beneficial. Tepper (1894) also stated that Geoscapheus ro- 

 bustus ate earthworms, grubs, and caterpillars. Froggatt (1906) and 

 Marlatt (191 5) attributed to Tepper the statement that cockroaches, 

 like Epilampra notahilis, which are found out-of-doors in Australia, 

 are carnivorous and feed on caterpillars and other soft-bodied insects ; 

 but Froggatt (1907) believed that this alleged behavior needed con- 

 firmation. 



A number of observations have been recorded which indicate that 

 sometimes cockroaches may be predatory. According to Ealand 

 (191 5), nymphs of the cockroach Pseudomops cincta fed on the Ar- 

 gentine ant Iridomyrmex humilis. In the laboratory, Eurycotis flori- 

 dana has been observed to catch and devour the wasp Anastatus 

 floridanus which parasitizes the eggs of Eurycotis (Roth and Willis, 

 1954a). Parcoblatta pensylvanica was observed devouring a larva of 

 Polistes sp. in its cell in a deserted wasps' nest (Rau, 1940). Brigham 

 (1866) saw a cockroach kill and eat a centipede four or five inches 



