The Infection of the ventriculus of the adult honeybee byNosema apis(Zander)

Abstract

1. Spores ofNosema apisnearly all germinate within 30 min. after entering the ventriculus of the honeybee.2. The cause of germinationin vivoremains unknown, but is probably not a change of osmotic pressure or pH and is probably not due to anaerobic conditions or an enzyme. The agent causing germination is probably unstable and is destroyed when removed from the bee.3. The anterior end of the ventriculus receives an initial heavy infection and the circumstantial evidence which this provides supports the theory that a free living ‘planont’ stage does not exist but that the parasite is injected directly into the host cell from the spore via the hollow polar filament.4. The central region of the ventriculus which contains many granules of calcium phosphate receives the lowest initial infection. It is considered possible that the granules inhibit the initial rapid development of the parasite by maintaining an unfavourably high level of pH until they are eventually dissolved by the slowly developing organism.