Nosema Apis - Effects On The Hive

Effects On The Hive

Nosema spores are spread to other colony members through fecal matter. The disease impairs the digestion of pollen, thereby shortening the life of the bee. A greater proportion of worker bees become infected than drones or queens, probably due to the comb cleaning activities of young bees in which drones and queens do not participate. Nosema infected bees do not attend or feed the queen to the same extent as healthy bees, which helps the queen to escape infection. When the queen becomes infected her ovaries degenerate and her egg laying capacity is reduced due to atrophy of the oocytes. Queens that become infected by the parasite during the brood rearing season are superseded by the bees.

The seasonal trend of typical infections exhibits low levels during summer, a small peak in autumn, and a slow rise of infection during winter. It is more common during times of confinement like winter and spring. In the spring the level of infection increases rapidly as brood rearing starts and while flight possibilities are still limited. Colonies in northern climates are more seriously affected than colonies in the south because of the increased amount of time bees are confined in the hive. Nosema, if left untreated, can cause queen supersedure, winter kills, reduced honey yields, and dwindling populations.