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Can female Drosophila melanogaster lay egg without males? I maintain our lab stock but find a line that seems to have all females (or all males). In the vial, I see some eggs laid, but the flies should have been flipped 2 weeks, ago but I don't see any eggs hatching or become larva.

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wow - so just like chickens... i wonder how this is an evolutionary avantage for the females? – shigeta Dec 1 '12 at 17:32
up vote 4 down vote accepted

Yes, I regularly have to collect female virgins (12500 of them in the last week). They will lay eggs especially when there is extra yeast available. It is actually a good way to check virginity - put some extra yeast grains in the vial when you collect them, leave them for a few days and then check for larvae, if they are not virgins there will be eggs and larvae, if they are virgins there will only be eggs!

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Very old females (such as those in vials that have not been flipped for a long time) will often lay unfertilized eggs in the absence of males. This happens to me occasionally when I am collecting virgins and then forget about them for a while.

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I find even young females do this, but do you add extra yeast to the vial? perhaps this stimulates mine to produce more eggs (see Ashburner, Sullivan and Hawley) more rapidly. – rg255 Nov 28 '12 at 10:25
Usually this happens to me when I'm collecting virgins, so there's often no yeast; this probably explains our discrepancy. – James Porter Nov 29 '12 at 0:55
cool, there is definitely research suggesting yeast increases egg production. and as useful way to check virginity whilst getting them really fired up ready to mate! – rg255 Nov 29 '12 at 13:32

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