Comparative fine structure of the corpus allatum from healthy and nosema-infected honeybees

Corpora allatal cells of healthy honeybees (Apis mellifera) had a nucleus with dispersed chromatin material, large mitochondria with a well-defined membrane in the cytoplasm, and axons between cells containing two kinds of neurosecretory granules. In cells of the corpora aHata of Nosema-infected bees, the chromatin material in the nucleus was electron-dense and much more compact. Mitochondria were smaller, with well-defined membranes and electron-dense matrices. Neurosecretory granules were rarely observed in the axon.