For our experiments (genetics) we use the following method: Females are
kept separated for minimal one week (action A). Then we transfer them
to a new vial and the males are added. One week later the flies are
removed. Some days later we start identify the offspring for their
mutant, and a crossing from this offspring is set.
We always assumed that action A resulted in females that weren't
fertilized any more. Our results didn't contradict that, because they
usually followed the theoretical values.
However, i've learned that females can hold sperm for at least two
weeks in their spermatheca, so when we mate them with an other mutant,
they should have still sperm with them from their own mutant males.
Because we don't recognize this in our results, this sperm is
apparently not or sparely used for fertilizing. Can anyone explain
Thanks in advance,