BIOTIC ASSOCIATIONS OF COCKROACHES — ROTH & WILLIS 34/ 



some of the odors produced by cockroaches have functions other than 

 defense or sex attraction. For example, Ledoux (1945) showed that 

 the species odor is largely responsible for the gregarious behavior 

 shown by Blatta orientalis and Blattella germanica. The olfactory 

 stimulus acts over a short distance only, and the source of this odor 

 in the insect is unknown. By washing Blattella germanica in warm 

 chloroform Dusham (1918) extracted a wax which had the odor of 

 the German cockroach. However, there is no evidence to show that 

 cockroaches respond to the same cockroach odors that are detected by 

 man. 



Certain cockroaches have recently been found to have odorous 

 secretions which are produced in tracheal glands. In Diploptera punc- 

 tata the tracheae leading to the second abdominal spiracles of nymphs 

 and adults are modified into odoriferous glands which produce a mix- 

 ture of 2-ethyl-i,4-benzoquinone ; 2-methyl-i,4-benzoquinone ; and 

 para benzoquinone ; this material is ejected as a means of defense. 

 The offensive odor emitted by adults and nymphs of Leucophaea 

 maderae also issues from the second abdominal spiracles (Roth and 

 Stay, 1958). 



Diploptera is capable of ejecting its quinones from either its right 

 or left tracheal gland according to which side of the insect is attacked 

 (pi. 36, A-B). Eisner (1958) found that the secretion repelled the 

 ant Pogonoinyrmex hadius (Latreille) (pi. 36, C) and the beetle 

 Galerita janiis Fabricius when they attacked the cockroach. The 

 spider Lycosa helluo Walckenaer was repelled by large nymphs and 

 adults of D. punctata but young nymphs were usually eaten promptly 

 (Eisner, 1958). 



Bordas (1901, 1908) believed that the "conglobate" gland (Miall 

 and Denny, 1886) , found in males of Periplaneta americana and Blatta 

 orientalis, was an odoriferous gland used for defense, but Gupta 

 (1947) has shown that in all probability this gland (the phallic gland) 

 secretes the outermost covering of the spermatophore. 



What appears to be mimicry occurs in some species of Blattaria. 

 The nymphs of many Panchlorini and Blaberinae vaguely resemble 

 sow bugs (Chopard, 1938). Certain members of the Perisphaerini 

 (e.g., Perisphaerus glomeriformis) from the Malayan region which 

 resemble sow bugs (Annandale, 1900; Hanitsch, 1915) can roll them- 

 selves up into a ball thus hiding their antennae and legs (Lucas, 

 1862). Although these cockroaches are found among dead leaves or 

 under stones, in places in which sow bugs are also found, the benefit 

 to either or both forms is questionable; Annandale (1900) believed 



