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Summary: preventing fly food falls.

Kathy Matthews matthewk at FLY.BIO.INDIANA.EDU
Fri May 19 14:24:25 EST 1995

Some of these are good solutions to whole-plug food falls, but liquid food
falls usually result from overinnoculation of the culture.  Too many females
= too many larvae = soupy cultures.  Prevention works best, and you will get
superior yields of adults from cultures grown at optimal density.  The right
number depends on the strain, and the quality and freshness of your food.  For 
healthy stocks such as Oregon-R, one or two females per vial and 5 or 6 per 
bottle is usually enough (one male for every 2 to 4 females is adequate for
most genotypes).  Weaker stocks will typically require 1.5X to 4x more
females than a healthy stock.  It takes a little longer to count out the
adults when establishing new bottles and usually isn't worth it for general
stockkeeping, but if you need a lot of adults or plan to make repeated use 
of the bottles such as in virgin collection it will save you a lot of time
and aggravation in the long run.  

Kathy Matthews			Bloomington Drosophila Stock Center
Department of Biology		MATTHEWK at FLY.BIO.INDIANA.EDU
Indiana University              MATTHEWK at INDIANA.EDU    
Bloomington, IN  47405-6801     812-855-5782

> 	Here are some ideas I received for making fly food less likely to
> collapse when a culture bottle is inverted.  Many thanks to:
> Greg Fitzgerald <gregory.fitzgerald at yale.edu>
> Harald Vaessin <hvaessin at magnus.acs.ohio-state.edu>
> Dan Rohwer-Nutter <dlrohwer at facstaff.wisc.edu>
> LarkClaass <larkclaass at aol.com> 
> Charlie Wright <cw117 at mole.bio.cam.ac.uk>
> Adrian Richard Gareth Pugh <argp at st-andrews.ac.uk>
> 	1. Add one or two sterile Kim-Wipes to act as a wick for additional 
> moisture.
> 	2. Boil the fly food longer - this will kill all the yeast in the
> media.
> 	3. Design your own media bottle to solve the problem.  (Ask Dan!)
> 	4. Tear off a piece from a sheet of cotton large enough to cover
> the surface of the media.  Poke it into the goo around the edges.
> 	5. Use a glass Erlenmeyer flask shaped bottle - this makes it
> harder for the food to fall out of position.
> 	6. Use more media per bottle.
> 	7. *Maybe* add more agar.  Be careful - females may not lay eggs
> into such media.
> --
> Matt Bernhardt
> University of Georgia                Fools multiply folly.
> bernhardt at bscr.uga.edu 

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