The Society for the study of flies (Diptera)

Rearing time coming up again!  The end of Feb down south is a really good time to collect dead wood or moss mat or swamp litter for rearing diptera.  In northern climes, one would do better to wait until the end of March to collect material, but I shall be out looking this next weekend.  Another good source is rotting old bracket fungi - for example the birch polypore, Piptoporus betulinus, brackets that have fallen off the tree and become half rotted (usually very slimy) around the base of the tree, or brackets of the turkey tail, Trametes versicolor.  Don't forget waterlogged dead wood from log jams in small streams.  Here are some larvae collected from rotting Turkey tail brackets a few weeks ago.  No idea what they are but I'm waiting with interest!

Any ideas, anyone?
Judy

Sorry, occasionally work gets too busy for fun with flies. Here are some photos of the method for rearing that I use.  For rearing from fungi I use coir fibre blocks or briquettes.  These are available to buy on the internet, but usually in rather too large quantities for convenience.  I have a friend who buys them in bulk for making his own compost and I buy them from him as I need them.  They need to be re-hydrated by soaking in a bucket with some water (needs to be damp, but not soaking). This makes rather a lot of material.  If I only want a small quantity, I hacksaw a chunk off one end of a block and re-hydrate that.  One can buy bags of loose coir fibre from garden centres, already hydrated.  One could use non-soil potting compost, but of course one does not need all the plant food that is added, the only thing the fly larvae need is a suitably moist medium of the correct structure for pupation.  I put the re-hydrated coir fibre into a plastic pot to about one third depth.  Supermarket food pots as shown are free and ideal in size.  After placing the fungal cap or bracket on the moist fibre, a white ex-curtain net or horticultural fleece portion can be secured over the pot with an elastic band.  Round pots are better - square pots are not so easy to make secure so the flies don’t make an escape under the elastic band.  The pots need to be checked weekly and sprayed with water if they are getting dry.

I keep the pots indoors, so they are warm. Under these conditions, fungus gnats can be emerging within two weeks.  Some flies take much longer.  If you put the pots outside in a shed, obviously they will be cooler and everything takes much longer to emerge.  They need to be checked daily after about a week to avoid missing things.  Inserting the end of the pooter under the net and catching the emerging flies is tricky and often they escape and go to the nearest window, where you can have even more fun chasing them with your pooter.  Some Platypezid larva collected in fungi in the autumn will not emerge as adults until the next year, so you need to be patient.  Some larvae need to have a cooler/cold period to mimic winter and then be brought into the warm to encourage emergence.  Teneral flies need to be allowed to harden up for a day at least before pinning, or colours will not be correct and their bodies may collapse.

For very small toadstools, rearing can be achieved on a miniature scale in a small plastic tube with coir fibre.  In the photo of the small tube one can see white mycetophilid fungus gnat pupae in cocoons at the junction with the coir. All records are most valuable if the fungus collected is properly identified to species in the first case.  I recommend going out with your local fungus group and asking for spare, named fungal specimens.  Even if the caps look look pristine and with no larvae, fly eggs are very often present and larvae appear in a short time.  Some fungi start emerging in the spring, so one can start in a month or so!
Judy

Last edited by Judy Webb (2010-03-25 21:45:40)

If you go out now and find some brackets of the Turkey tail, Trametes versicolor, on logs in a damp or wet place, you might find some Platypezid puparia just under the surface of the gill layer, as in these photos, ready to hatch.  in these photos I just scratched off the frass lumps and found circular holes with a puparium visible in each.  They are set up to rear and watch this space to see if I am lucky with flies soon...
Judy

Not long to wait, because here are the flies!  All black males emerged first, then one really beautiful silver and black female. No new discoveries here, from the female pattering this appears to be the Platypezid Polypivora ornata which is well known to breed in Trametes versicolor.  Photography was very difficult because, although the flies were reluctant to fly, they were constantly rushing about randomly all over the surface.  Persuaded them to walk onto my finger, but mostly too active until they ran up my arm onto my black fleece.  Then both sexes suddenly became still and sat motionless for some of the photos attached here to be taken.  The silver patches on the female flashed in the sunlight as she moved.

Judy

Last edited by Judy Webb (2010-05-27 00:10:50)

Latest rearing !! - yesterday from a pot set up with  a cap of Pluteus cervinus from a woodland near Oxford, collected in October last year.  Some pretty female Platypezids.  A couple of all black males emerged from the same pot this evening.

Some poor photos, but anybody any ideas on what species?

A reminder that Platypezids are one of the featured groups of the DF Advanced Workshops this March at Preston Montford.  No doubt I'll be able to identify them after that course!

Judy