Accessory Cells of the Mycetome in the Rice Weevil, Sitophilus oryzae:1 Post-Embryonic Development

Abstract

In larvae of the rice weevil, Sitophilus oryzae (Linnaeus), two clusters of cells are located on the anteriolateral surfaces of the mycetomes, but in the adults are relocated on the walls of the gizzard in the foregut. In the early larval stages, the cell clusters vary in shape and are ca. 40–50 I¼m in diameter. In the adult, each cluster is ca. 100 ¼m in diam and consists of 15–20 cells. The size of cell clusters from aposymbiotic larvae are similar to the size of the clusters from normal larvae; thus, unlike mycetomes which develop only in the presence of the bacteria-like symbiotes, the cell clusters develop independently. Granular contents in the cells increased during larval development and were more numerous in the pupal stages. Although symbionts were in the cells of some pupae and adults and never in larvae, the accessory cells may be part of the through which symbionts are passed to the o¶cytes.