Abstract
Laodelphax striatellus harbours intracellular yeastlike symbiotes in the fat body, transmitting them to the next generation through the female ovary. High temperature, 35°C, destroyed the yeastlike in the mycetocytes. Under the continuous high temperature no adults were obtained. The population of symbiotes in the 5th-instar nymphs, which were previously exposed to the high temperature for 3 days after hatching (heat treatment), was reduced; approximately one twentieth of that in the normal 5th-instar nymphs. These heat-treated insects showed poor growth in spite of sufficient sucking of rice plant juice. More than 70% of the heat-treated 5th-instar nymphs did not become adults and a number of them died. In some of them, the adult duticle was not only deposited in part. The high temperature also exerted an infuluence on fecundity of this species. The heat-treated insects seem to be useful for the further study to explore the role of the yeastlike symbiotes.
