How to anesthetize Drosophila? Homemade

[Kevin_r]

Hi!
I am hoping for some help with anesthetizing my Drosophila population. I am conducting a study to identify different species of Drosophila near our house.
I cannot procure any chemicals (due to travel restrictions). I wish you could share any ideas on how to anesthetize them.

I tried soaking them in ethanol. However, I find it hard to manipulate the specimen when observing them under the scope.

Cheers!
Stay safe!

Sincerely,
K

PS: Any tips in handling flies/insect would also be a great help!

[BramHuntingNematodes]

You could try putting them in the freezer.

[Hobbyst46]

Try using carbon dioxide gas. I heard it works. It can be safely and easily prepared from a little vinegar and some baking soda, for example, or from citric acid (in water) and baking soda or of a calcarous stone. Depending on the size of the jar where the flies are, but in general, a teeny-tiny amount is needed. Carbon dioxide is heavier than air. Prepare it in an external jar and direct a stream of the carbon dioxide into the fly jar. Try just a short exposure of the flies in the jar. Do it in a ventilated space, though. And protect your eyes against splashes of the acid.
Might be even simpler to release the carbon dioxide gas from a bottle of carbonized drink (instead of the acid method). Again: these are just thoughts, did not do them myself.

[Kevin_r]

You could try putting them in the freezer.

WIll try this, as soon as I get new sample collection bottles.

[Kevin_r]

It can be safely and easily prepared from a little vinegar and some baking soda,

Nice idea.
I'm not just sure how to collect C02 and put it in the jar (without them escaping).

[Hobbyst46]

It can be safely and easily prepared from a little vinegar and some baking soda,

Nice idea.
I'm not just sure how to collect C02 and put it in the jar (without them escaping).

A brief look into the literature shows that CO2 should indeed do the job. Although side effects are possible, depending on the age of the fly and others.
An exposure to a mixture of air and CO2 for several minutes.
The flies should recover within about 10 min.
So I would experiment a little - start with, say, a 50% strength of CO2. Direct a stream of the gas from the gas generator into the closed jar that contains the flies. If the latter is covered with a net, the net should be replaced with a solid lid that has two small openings (say 1/4" bore). Into one of them the end of the tube that leads the gas from the generator is inserted. The other hole serves for vent. Tubings and building materials can be simple plastic (or glass if you can bend a 1/4" glass tube over a gas flame). But I would opt PP or PE plastic.

I can think of several variants of a generator. To design it, would help to know the shape and size and volume of the jar that contains the flies. Then later I can post a scheme.

Edit: for long term research, might consider another source of CO2: compressed CO2 in a cylinder.

[MichaelG.]

Edit: for long term research, might consider another source of CO2: compressed CO2 in a cylinder.

The once-very-popular SodaaStream [and similar] fizzy drink makers should provide a conveniently sized cylinder and valve.

MichaelG.

.
Edit: ___ another idea [new to me] is ‘pelletized’ Dry Ice !
which I found mentioned here: https://youtu.be/l-a3pISQLQg
... we could skip the dodgy process and just use one pellet in a sealed jar.

[Hobbyst46]

Edit: for long term research, might consider another source of CO2: compressed CO2 in a cylinder.

The once-very-popular SodaaStream [and similar] fizzy drink makers should provide a conveniently sized cylinder and valve.

MichaelG.

.
Edit: ___ another idea [new to me] is ‘pelletized’ Dry Ice !
which I found mentioned here: https://youtu.be/l-a3pISQLQg
... we could skip the dodgy process and just use one pellet in a sealed jar.

Michael, the thought had passed through my head, but dry ice is practical in a research lab, where they can store it in large isolated chests (it is sold in blocks, AFAIK; having seen the video clip of the link, maybe pellets also, but storage remains a problem). And the supply must be weekly or biweekly renewed. In addition, it is wasteful to break a block into small pellets (most of the stuff will evaporate and be gone). It is also not so reproducible - quite difficult to weigh <1 gram quantities of dry ice accurately.
So, for home use, IMO, it is not so practical. Unless we are talking high-volume work, flocks of flies...clouds of flies...
The generation of carbon dioxide is fairly easy, once you set upon a reasonable protocol. We need to know a little more details of the OP's facility.

[MichaelG.]

Thanks for the Dry Ice information, Doron

I already have several of the small SodaStream cylinders, so it’s not likely to be needed here ...

I just thought that ‘Pelletized’ Dry Ice might have possibilities; but if storage is impractical, then perhaps not.

MichaelG.
.
Edit: I see what you mean !
My home Freezer doesn’t reach -78°C

[Hobbyst46]

My home Freezer doesn’t reach -78°C

Not only that. Dry ice sublimes into CO2 gas; a tightly closed freezer will likely explode under the inner pressure; a non-tightly closed freezer will likely put the whole family to sleep, not just the Drosophila...

[Mraster2]

Yeast and sugar in warm water
in a suitable bottle with a pipeline to the fly chamber,
or use another inverted water-filled bottle over water bath to collect the displacing gas.
CO2 being heavier than air it can be poured from a filled bottle** into the fly chamber (through a mesh top)

PS If using malted barley as the sugar a beverage is a side product ! !

**PPS not easy to see CO2 ! So practice by extinguishing a candle (tea light) in a jar, - once upon a time used as a party trick.

[MichaelG.]

Edit: I see what you mean !
My home Freezer doesn’t reach -78°C

That’s strange ... there was supposed to be a relevant link included in that Edit, with notes about storage, etc.

Blame the typist

https://www.chillistick.com/all-product ... sizes.html

[Hobbyst46]

Edit: I see what you mean !
My home Freezer doesn’t reach -78°C

That’s strange ... there was supposed to be a relevant link included in that Edit, with notes about storage, etc.

Blame the typist

https://www.chillistick.com/all-product ... sizes.html

This turns out to be a fun discussion - just what we need in these gloomy times:
Citing from the chillistick ad:
"Dry ice has a short shelf life. The more ice you order the longer it lasts. Typically it can lose around 2kg per day. The 2.5kg will usually last for 24hrs if unused and left un-opened."
And 2.5 Kg is the minimum amount they supply, for the cost of ~27 BP in the UK. Indeed in pellet form, no need to break blocks. Blocks, by the way, can keep for several days in an isolated ice-box. But let us stay with the chillistick pellets. They naturally evaporate faster.

My initial assumption was that the OP has, say, 10-20 flies in a 100ml jar. A 0.2 g of dry ice will produce roughly 100ccm of CO2 gas that will (I believe) will put the flies to sleep, so the experiment proceeds. Next day, another jar of flies can be treated. And that's it, the dry ice supply must be renewed.
If on the other hand there is a 10 liter jar of flies, 20 g of dry ice are needed. Still, the same logistics.
But, it the flies initially are free in a 1000 liter chamber or tank, 2 kg of dry ice will be very efficiently used, all at one day.
With such quantities of CO2 I would suggest severe precaution of the operators, lest they fall "asleep" as well...

[MichaelG.]

A 0.2 g of dry ice will produce roughly 100ccm of CO2 gas that will (I believe) will put the flies to sleep, so the experiment proceeds. Next day, another jar of flies can be treated. And that's it, the dry ice supply must be renewed.

Hence the significance of my comment about not having a -78°C freezer available
... and my delight at already owning several SodaStream cylinders

MichaelG.

[Kevin_r]

It can be safely and easily prepared from a little vinegar and some baking soda,

Nice idea.
I'm not just sure how to collect C02 and put it in the jar (without them escaping).

A brief look into the literature shows that CO2 should indeed do the job. Although side effects are possible, depending on the age of the fly and others.
An exposure to a mixture of air and CO2 for several minutes.
The flies should recover within about 10 min.
So I would experiment a little - start with, say, a 50% strength of CO2. Direct a stream of the gas from the gas generator into the closed jar that contains the flies. If the latter is covered with a net, the net should be replaced with a solid lid that has two small openings (say 1/4" bore). Into one of them the end of the tube that leads the gas from the generator is inserted. The other hole serves for vent. Tubings and building materials can be simple plastic (or glass if you can bend a 1/4" glass tube over a gas flame). But I would opt PP or PE plastic.

I can think of several variants of a generator. To design it, would help to know the shape and size and volume of the jar that contains the flies. Then later I can post a scheme.

whoa! There's no need to design one for me. I am very thankdul for the ideas.

[Kevin_r]

Hi guys!

I was wondering if you have any idea of using mothballs/naphthalene ball in "anesthetizing" fruit files.

[Hobbyst46]

Hi guys!

I was wondering if you have any idea of using mothballs/naphthalene ball in "anesthetizing" fruit files.

AFAIK:
Naphthalene and chlorinated chemicals in mothballs are toxic and carcinogens. I thought they were all phased out.
However, and irrespective of that, for putting flies into sleep, from which they awake healthy (and maybe refreshed), IMHO a generally accepted, proven and universally recognized anesthetic is preferred. An experimental chemical might cause side effects, maybe even death depending on the dose.

[Kevin_r]

Hi guys!

I was wondering if you have any idea of using mothballs/naphthalene ball in "anesthetizing" fruit files.

AFAIK:
Naphthalene and chlorinated chemicals in mothballs are toxic and carcinogens. I thought they were all phased out.
However, and irrespective of that, for putting flies into sleep, from which they awake healthy (and maybe refreshed), IMHO a generally accepted, proven and universally recognized anesthetic is preferred. An experimental chemical might cause side effects, maybe even death depending on the dose.

Thanks for the information!
I will make sure to take note of that.

[Greg Howald]

If you don't want to kill them you can put a drop of glycerin on the wet mount to slow them down.
Greg

[BramHuntingNematodes]

I think the purpose may be to vivisect the fly.