Protocols and techniques
Virgin collection
In order to perform crosses, all of the females used must be virgins.
Virgin females (denoted by the symbol ) have several defining characteristics
that separate them from mated females:
1. Very pale
2. Dark spot seen in abdomen (the meconium, waste products remaining
from pupation).
3. Distended, large abdomen
Note that very young, newly eclosed, females can have their wings folded and the
abdomen may not have inflated yet. One of the best indicators for a virgin female
is the presence of the meconium in the gut.
© FlyMove
The flies eclose early in the morning, therefore this is the best time to collect
virgins however it is possible later in the day. If this is an issue, the safest method
to collect virgins is to empty the vial of flies a few hours prior to collecting
virgins. After eclosion, the flies present are likely to be virgins for approximately
8-­­10 hours, although they will be more difficult to identify as they mature.
As newly eclosed males are also very pale, and can also have visible meconium
be sure to check the genitalia of the fly!
1