fruitflies - where do they come from?

Just have your vacuum cleaner close to hand. The ones in my house used to disappear behind the curtains

annsixty ? If only the little devils had stayed still! The experiment concerned sex linked inheritance in Drosophila. I've only recently sent a book on the subject to a charity shop. Goodness knows why I kept it for 57 years.

The very idea of trying to sex fruit flies has captured my imagination.
I shall go to sleep happy tonight, pondering on that.

But where do they come from *Varian? They're not to be seen until the weather gets hot and then the fruit bowl (In the dining room, nowhere near an outside door or open window) is suddenly smothered in them. So, I give the fruit a wash over and put it, fly free, in the fridge - and there's no flies in the dining room. Where did they go? They seem to conjure themselves from the air and vanish back into it again.

Varian your post brought back memories of a Biology practical exam when I was at College. Can't remember the exact genetics question but to answer it we had to anaesthetise Drosophila with just enough ether to knock them out, too much and they would have died. Then, under a microscope we had to sex them, noting eye colour and other characteristics. The lab was full of escapees who had recovered too early from the ether, scuppering the experiment, together with sighs and mutterings from the students.

I’ve had plagues of these critters in the past and fair few around at the moment. Have partly solved it by putting little sticky strips beside my many houseplants and on my window sills. I'm amazed and slightly disgusted at how many the traps catch. Might have a go at your solution grannygravy.

You learn something every day Varian!

Fruit flies (drosophila) are a very useful laboratory animal used widely in the study of genetics because they have a life cycle of fourteen days so they work well with a university timetable.

Hmmmm devious GrannyGravy, I like it! A method worth pinching!

I put out a shallow bowl with a solution of vinegar and sugar, cover with cling film and pierce film with lots of little holes. The silly flies are attracted to the solution fly in but cannot get out.

I cut up a pineapple last night and they were everywhere. I hadn't noticed them much before.

Yes had a banana going off which I d forgotten and they were having a field day tiny tiny fast little buggers