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). The flies have been in the vial for two weeks, but I don't see any eggs hatching or become larva.

  • $\begingroup$ wow - so just like chickens... i wonder how this is an evolutionary avantage for the females? $\endgroup$
    – shigeta
    Dec 1, 2012 at 17:32

2 Answers 2


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 (in case a fly hatched early and was already mature, or a male made it through sorting etc.) - 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!


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.

  • $\begingroup$ 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. $\endgroup$
    – rg255
    Nov 28, 2012 at 10:25
  • 1
    $\begingroup$ Usually this happens to me when I'm collecting virgins, so there's often no yeast; this probably explains our discrepancy. $\endgroup$ Nov 29, 2012 at 0:55
  • $\begingroup$ 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! $\endgroup$
    – rg255
    Nov 29, 2012 at 13:32

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