[Drosophila] Preserving Drosophila by Freezing?

[Qin, Hongtao]

Greeting all, 
 
I noticed from the following link that detailed protocols for preserving Drosophila by freezing were made available to the fly community in 1993. 
http://www.bio.net/bionet/mm/dros/1993-April/000011.html
However, it seems like preserving Drosophila by freezing is still not an option for keeping fly stocks in many labs. Does anyone know why? Is it because the protocols were not reproducible by other labs, the cost was too high or other problems? Is any lab still trying hard to develop a better protocol?
 
Thanks, 
Hongtao
 
Hongtao Qin
Cold Spring Harbor Laboratory
1 Bungtown Road
Cold Spring Harbor, NY 11724
Phone: 516-367-6826