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Re: Growing blood worms

John M. Burns wrote:
> 
> Anyone out there growing their own blood worms?  If so, how do you do it?
> I haven't hit on any internet references to the procedures.  Can anyone
> point me to some (if there are any).  TIA
> 

Hi John,

Some years ago I had a culture of Chironomus riparius going, but was not
able to continue it over several generations, probably because I lost
interest and neglected them.

To be successful you have to:

1) Find a starter culture
2) Feed the larva (the 'bloodworm" stage)
3) Successful pupation
4) Successful imago emergence
5) Successful mating & oviposition

Step 1) - You can start with a culture of a *known* gnat, or obtain the
bloodworms from the wild. Chironomus riparius is used in toxicity
studies of sediments. EPA has a research lab in Bent Harbor, MI where
they culture them (also at other sites). Large environmental analysis
labs will probably have them too. EPA has culturing directions, as does
"the bible" of water analysis "Analytical Methods for Water and
Wastewater Analysis" (or a title close to it!).

You can obtain your culture from the wild, chancing that the critters
you collected are difficult (or impossible) to culture:
Prepare a bucket of water with leaves etc, just like one does it for
mosquito culture, with rotting leaves on the bottom. After a while,
after two or three generations of mosquitoes matured (also an excellent
fish food) decant the water and look in the mulm for bloodworms - red
wriggly "worms". They are difficult to see, because they camouflage
themselves with leaf parts.  Collect them and there you are! The more
larvae you have, the better the chance for success in steps 4 and 5.

Step 2) For growth they need a substrate. It can be a blended unbleached
(brown) paper towel (i.e. paper pulp) or the original leaf muck.
They eat finely ground fish food. I fed mine ground Tetramin Staple. As
the food is consumed, you just add more. They seem not to mind low
oxygen tension in the water - they have hemoglobin for that purpose,
hence "BLOODworms".

Step 3) I newer had trouble at this stage. When first pupae are noticed,
it is a good idea to transfer the entire culture to a cage suitable for
step 5. I used a shallow dishpan as a culture vessel and placed it
inside the cage.

Step 4) The emergence has two pitfalls:
	a) Some individuals fail to emerge at all, or emerge only partly.
	b) They emerge NOT synchronous, thus complicating step 5 (that is the
reason to start with many individuals in the culture). I don't think one
can do anything about either problem.

Step 5) After emergence one can offer the midges some dissolved honey
(about a 10% solution, as drops on a substrate). 
To mate, the midges need air space. For Chironomus riparius one needs
about two cubic feet of space. I used a 10-gallon tank (a 20 tall would
have been better) covered with mosquito netting. I just placed my
culture container in the tank and provided another container (with
rotting leaves) for oviposition.

If you have several male/female pairs, they will do the rest without any
help, depositing a gelatinous egg mass. (You should receive 3-5 such egg
masses as a starter culture.) 
BUT, if only one or two midges emerge at a time, they most likely will
not be able to mate and that will be the end of the line. That is
exactly what happened to my culture - I just got ONE egg mass!

Hope that this helps. If anybody has successfully cultured Chironomus
riparius (or other midges), please let me know - you might have a better
method. Anyway, I would like to try my hand at it again.

Best,

George