# More ... > Beekeeper education >  Module 3 - Nosema apis

## Mellifera Crofter

Can somebody help me to understand the life cycle of a microsporidian?

I understand that the N. apis spores are eaten and move to the ventriculus.  Celia Davis says that this is where they germinate and infect the epithelial cells (p.62 - _The Honey Bee Around and About_).  Once inside the cells, they multiply.

On p41 she explains more about the 'firing' of a tube into the host cell, and how the organism then moves through the tube into the cell.  Back on p62 she also has a picture of a spore with a hollow filament which I imagine is the tube she described.

I'm not sure when the 'firing' happens.  Is it the spore that 'fires' its 'harpoon', or is it the actual organism that 'fires' a 'harpoon'?  So, when it germinates in the mid gut, do the spores 'fire harpoons' into the epithelial cells and the germination takes place there, or do they actually germinate in the mid gut, and it is the organism that 'fires a harpoon' into the epithelial cells?

A further question:  How does the multiplying of N. apis work?  She says they multiply in the epitheleal cells; the cell dies; new spores are formed.  But don't they multiply by forming spores? Or do they multiply by division?

I hope I managed to explain my confusion.
Kitta

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## Mellifera Crofter

Sorry for having asked.  I think I found the answer:  The spore germinates - meaning it gets ready to inject its contents into an epithelial cell.  Once the organism is inside the cell, it becomes a 'sporoplasm' and produce new spores.  I think I've got it now.
Kitta

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