Ultrastructural changes in the secretion granules of the hypopharyngeal glands of the honeybee infected by Nosema apis and after treatment with fumagillin.
Electron-dense secretion granules were numerous in the hypopharyngeal glands of healthy honeybees. In the hyopharyngeal glands of honeybees infected by Nosema apis, these granules appeared to have increased in size and lost their electron density, possessing a core area that consisted of numerous smaller granules, and a slightly electron dense fringe area, which in some cases possessed a crystalline structure. In the hypopharyngeal glands of infected honeybees after treatment with fumagillin, the secretion granules were also large and slightly electron dense, but the granular content was homogenous. Some of these granules were also partially crystallized. These ultrastructural changes in the secretion granules of diseased and fumagillin treated bees, is probably associated with a change in secretory activity of the glands.
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Bee Diseases Research Laboratory, Agriculture Canada Research Station, Box 29, Beaverlodge, Alberta, Canada, T0H 0C0.