Thursday, July 16, 2015

The great divide in how researchers manipulate fruit flies

How do you manipulate your Drosophila, Paint brush or watch maker's forceps? You Tell me!

I bet when you read "manipulate" you thought I meant genetic manipulation, eh?

So last night while I was "pushing flies" - collecting flies for a genetic cross (mating scheme), - I was switching back and forth between my two favorite instruments (paint brush with short hair and forceps) to move around anesthetized flies (sorting based on genotype, sex, etc). For some reason (even though I have been a fly pusher for 18 years) I started to think about whether the brush or forceps was more efficient. After all, I have sorted (at a rough guess) several hundred thousand flies (or more?) during this time. Small efficiencies could save huge amounts of time.

For me I generally use forceps when I am collecting small numbers of distinct individuals (based on genotype & sex) in a large pile on the anesthesia plate (a plate with a porous surface where we pump carbon dioxide through to knock out flies). I use the brush when it is many more individuals, and there are (relatively speaking) more of them, like for "virgin" collecting (collecting very young females who have not yet mated with a male, and so are not storing sperm).

So I wanted to know from fly peeps around the world; paint brush? forceps? other? Why this choice?


  1. Have about 50 brushes, half marked with tape, half without- for stuff where preventing contamination is critical have a pot of virkon sol next to CO2 pad, and brush get chucked in there after each vial/replicate. Once have used both sets of brushes, rinse and dry the first set (so they will have had at least 15min in virkon). Periodically spray fly pad with virkon solution, let bubble, then rinse w 70% ethanol. I have data showing cross contamination (when infecting flies with virus) is not detectable via CO2 pad. Probably overkill for most folk though!

    We've had several people become allergic to flies recently, main cause seems to be intensive pooter/aspirator use (one of these people had worked with flies for 8 years prev). Coupled with the risk of cross contamination I would not use a pooter anymore, despite the convenience!

  2. Ben,

    Thanks. I am curious why virkon, and not just 70% ethanol for disinfecting?