How to raise sling food: a brief guide for fruit flies

Le Wasp

Arachnoknight
Old Timer
Joined
Oct 25, 2007
Messages
245
After reading that quite a few hobbyists keep fruit flies for their slings, I figured I'd share how I raise them.

First, instead of ordering a culture of fruit flies, I just collect ones that are locally abundant to start a culture. Fruit flies are present pretty much anywhere, so all you have to do is make some bait and leave it where they can find it. Just take a piece of organic fruit and wound it so the fruit flies can get to it, then leave it underneath a tree. If it's not beginning to ferment already, put a few granules of yeast on the fruit. Make sure you put your fruit bait in the bottom of whatever you're going to keep them in so that all you have to do is put the lid over it. The flies will fly away at the slightest disturbance and you want to catch as many as you can to start the colony. If you're paranoid about pesticides, raise the flies for a generation or two before using it as a feeder culture.

For the container, I use a small plastic display box that I use for work. You can get similar things from the container store. I bored holes in 3 walls, covered 2 with screen, and the third with a sponge. The sponge keeps the flies in when you harvest them.

To collect the flies for feeding, I use a self-made aspirator. You can get fancy ones at BioQuip, but they're easy to make. Just take two sizes of clear tubing from Home Depot and put a small square of screen between them. Then, when you're ready to collect flies, just push the sponge back enough to fit the aspirator tube through, and suck up some flies!

To make feeding (and watering) easier, I put corks in all my sling containers. This way, I can just tap the flies out of the aspirator without having to open and close each container. Make sure the holes in your sling cages aren't large enough for flies to get out of!! This is terribly annoying.

And that's about all there is to it! I find this a pretty easy way to mass-rear a bunch of fruit flies. A word of caution though: It's been shown that feeding fruit flies alone to true spiders doesn't provide enough nutrition for proper development. My experience is that slings fed only fruit flies develop slower than those supplemented with other insects. So make sure to occasionally feed your slings other insects when feeding mainly fruit flies.

I've been trying to culture other types of larger fruit flies (true fruit flies instead of vinegar flies), in hopes of finding a more nutritious food source. Unfortunately, I haven't been successful. Perhaps these other flies require a more complex diet. I've tried various blends of diet usually used by fruit fly breeders, but still no offspring have come through. If anyone else has better luck, let me know!
 
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flamesbane

Arachnobaron
Old Timer
Joined
Dec 10, 2008
Messages
529
Flightless fruit flies such as D. hydei and D. melanogaster are incredibly easy to culture, and have the benefit of not being able to fly. This means no aspirator or escapees.

Not that what your doing here isn't thrifty, I just think that the small cost of getting a starter culture and media is worth it. A single properly made 32oz fruit fly culture can produce 1000-3000 flies over the course of a month (less with D. hydei, more with D. melanogaster).
 

telow

Arachnobaron
Old Timer
Joined
Feb 24, 2004
Messages
446
arent fruit flies 90% water ?
they arent the only food source i would use as they arent
a real good source of food for much of anything realy
nut they would be a good starter for tiny slings

just my thoughts on fruit flies
 

killy

Arachnoknight
Old Timer
Joined
May 20, 2009
Messages
249
After reading that quite a few hobbyists keep fruit flies for their slings, I figured I'd share how I raise them.
Beautiful! This the kind of thing that gets filed under "Now why didn't I think of that?!?!?' THANK YOU FOR SHARING.

Just wondering, would the "chill-down" method, so successfully applied to crickets, work with fruit-flies too (i.e. slowing them down for easier handling by refrigerating them before a feeding)?
 
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