A Note on Some Preliminary Observations on the Effect of the Antibiotic Terramycin on Insect Symbiotic Micro-organisms

Abstract

Micro-organisms that seem to be symbiotic are known to occur in many insects (Steinhaus, 1949). Often these micro-organisms are retained for at least a part of their iife in special organs in the insect's body called ‘mycetomes’. Mansour (1935) following a study of a number of beetles cnntaining micro-organisms concluded, in the two closely related species Sitophilus granarius (L) and Sitophilus oryza (L) that while both species have mycetonies only S. oryza had micro-organisms; a conclusion that his received some general acceptance (Steinhaus, 1946; Wigglesworth, 1947). Thus it could be questioned if the micro-organisms in S. oryza were of benefit to it since S. granarius survived apparently without any (Mansour). However, it has been shown that in some beetles (Blewett & Fraenkel, 1944), in the body louse (Aschner, 1935), and in the hug, Rhodnius, (Brecher & Wigglesworth, 1944) the associated micro-organisms are of considerable importance to the insect. It therefore seemed worth while to study further the condition existing in S. oryza and S. granarius; and in the early stages of this work some interesting phenomena have been observed.