Most likely the smaller hypopharyneal glands and earlier foraging in N. apis infected workers are due to the fact that
Nosema infects the epithelial cells of the midgut, therefore greatly reducing the host’s ability to digest pollen, which
is needed for the development of glands. Impaired protein metabolism are deduced by lower proteolytic activity of
the mid-gut, lower amount of amino acids in hemolymph, lower levels of proteins in the fat bodies (reviewed by Kralj
and Fuchs, 2010) and lower protein levels in hemolymph in infected bees (Z.Y. Huang and T. Zhou, unpublished
data). Inadequate nutrition could fail to increase vitellogenin, which normally inhibits JH production. Therefore JH
increases prematurely in these bees with a poor protein nutrition.