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Re: Bloodworms (was LFDigest V2 #335

> Hi,
> Can you send me any information on the breeding & culturing of
> bloodworms. Please Email to : pittskevin at hotmail_com
> 
> Thanking you
> Kevin

Hello Kevin,

Some years ago I had a culture of a blood worm, Chironomus riparius, 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. Large environmental analysis labs will probably have
them too. EPA has culturing directions, as has "the bible" of water
analysis "Analytical Methods for Water and Wastewater Analysis" (or
something close to it!).

You can obtain your culture from the wild, chancing that the critters
you collected are difficult 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 particles.  Collect them and there
you are! The more larvae you have, the better the chance for a
successful culture 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 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). 
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 receive 2-5 such an 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.

Hope that this helps. If anybody has successfully cultured Chironomus
riparius or another "bloodworm" over several generations, please let me
know, because I would like to try my hand at it again.

Best,

George