Science Questions

There are very few houseflies to be seen in the wintertime but there are some. Do they hibernate in the winter months or do they move to warmer climes? Clive

No, I don’t think flies do go on holiday, they don’t migrate. Flies only live for a maximum of two months but usually only about 15-24 days. There’s a possibility that some of them might hang on until winter but they generally do much better when it’s warmer. They can survive over winter and that’s actually another stage in their lifecycle which is as larvae or pupae. What happens with flies is they will lay eggs which hatch into larvae, otherwise known as maggots, which is lovely. They will be alright when the temperature drops and they’ll hang around in food and faeces and things like that. Lovely. If you’ve got a pile of horse manure in your garden they might hang out there.

The larvae grow and then they will pupate so they will wrap themselves up in a tight little packet which will then sit around and survive the winter. That hatches into an adult. So the ones you’ve seen in winter you’ve notice are quite slow. They don’t fly so quickly – much easier to swat. They’re really the ones from the tail-end of the summer population waiting to regrow again in the spring time.

May 2008