DROSOPHILA HEAD COLLECTION

Equipment

flies frozen in 250 ml centrifuge bottles
sieves: 106, 355, 600 and 850 mm
paintbrush
collection tubes
funnel
dry ice
jacket, hat and gloves!

Preparation

1. Freeze flies in 250 ml centrifuge bottle(s) @ -80oC („30'').
2. Cool sieves @ -20oC for „ 20'' prior to use.

Procedure

1. Arrange sieves as follows (top to bottom):
parts retained
850 mm bodies
600 small bodies + some heads
355 heads
106 fly dust, legs

2. Shake flies with moderate strength 4-6X for 3" each time.

3. Pour flies onto top sieve.

4. Brush gently so as not to jam flies into mesh openings. Females tend to be a little larger than males; you may want to pass the 600mm material back over the 850 mm sieve 2- 4X.

5. Collect heads into tared tubes. Keep frozen until used. Obtain a weight (?).