SYMBIONT OF BROWN-WINGED GREEN BUG, PLAUT IA-STALI SCOTT

The presence of a symbiont of the brown-winged green bug, Plautia stal i was confirmed. Long bacilliform microorganisms were commonly observe d in the cytoplasm of epithelial cells of gastric caeca on the surface of the posterior midgut. Each cavity of the caeca opened into the mid gut cavity via a fine pore. Symbionts that had multipled in the myceto cytes were released in the cavity of the caecum following degeneration of the host cells. Thereafter, the symbionts were extruded into the m idgut cavity through the fine pore. It is possible that the symbionts are smeared on egg surfaces by adult females during the oviposition, a nd the hatched lanae may ingest the symbionts. The mycetomes may produ ce vitamin Al or carotin and vitamin E, because these substances were only detected in the caeca. Vertical transmission of the symbiont was inhibited by disinfectant, and larvae hatched from sterilized eggs did not become adults due to death from opportunistic infections caused b y various microorganisms such as fungus, Serratia and/or a Staphylococ cus-like bacteria. Application of Serratin-like bacteria an the egg su rface caused high mortality of 2nd inster larvae.