BIOTIC ASSOCIATIONS OF COCKROACHES — ROTH & WILLIS 99 



stances, as suggested by Keller (1950), or function in some other way 

 is still to be determined. Brooks (1954) concluded that the amount 

 of vitamin-containing food required for increased growth by aposym- 

 biotic cockroaches is much greater than the known vitamin require- 

 ments ; hence the factor (s) needed is unknown and present in low 

 concentration, or it serves as a precursor of a second factor (s) whose 

 synthesis is aided by the bacteroids. Brooks (in Richards and Brooks, 

 1958) has since found that the bacteroids of Blattella germanica "can 

 supply the insect with B vitamins, amino acids and some larger protein 

 fragment." 



Gier (1947) stated that the symbiotes of cockroaches are generically 

 all the same. However, as the symbiotes are presumed to have been 

 associated with cockroaches for over 300,000,000 years (Buchner, 

 1952) they may be assumed to have developed specific differences that 

 link them inseparably to their respective hosts. Ries (1932) trans- 

 planted symbiote-containing fat body from Blatta orientalis into the 

 mealworm and larva of Ephestia kuhniella, and from Blattella ger- 

 manica and Stegobium paniceum {=Sitodrepa panicea) into B. 

 orientalis. The implants did not become established in the new host, 

 although most of the transplantations were successful in that the hosts 

 survived and the implants remained intact for some time before they 

 were encapsulated by host tissue. Brooks ( 1954 ; Brooks and Richards, 

 1956) transplanted fat body of Periplaneta americana and B. orientalis 

 into aposymbiotic B. germanica. The growth of the cockroaches in- 

 jected with foreign tissue was not different from that of aposymbiotic 

 controls. Sections of host insects did not contain mycetocytes and no 

 bacteroids were found. Haller (1955a) injected bacteroids or im- 

 planted mycetocytes of B. germanica into gryllids, acridids, and 

 locustids. These implants and innoculations were rapidly destroyed 

 by the hosts. But as Richards and Brooks (1958) have pointed out, 

 none of these experiments provide information about the specificity 

 of the bacteroids themselves. 



COCKROACHES IN WHICH BACTEROIDS HAVE BEEN FOUND 



Bantua stigmosa. Fraenkel (1921). 



Blaberus craniijer. Brooks (1954); Brues and Diinn (1945); Hoover (1945). 



Blaberus giganteiis. Blochmann (1892). 



Blatta orientalis. Blochmann (1887, 1888, 1892) ; Bode (1936) ; Brooks (1954) ; 



Buchner (1912) ; Cuenot (1896); Fraenkel (1921) ; Frank (1955, 1956); 



Gier (1936, 1947) ; Glaser (1920) ; Gropengiesser (1925) ; Gubler (1948) ; 



Heymons (1895) ; Hollande and Favre (1931) ; Hoover (1945) ; Hovasse 



(1930) ; Javelly (1914) ; Keller (1950) ; Koch (1949) ; Mencl (1907)?; Mer- 



