[Drosophila] Mites in stocks from Bloomington

[Kevin Cook]

Dear colleagues--

We regret to tell you that we've discovered mites in Bloomington 
Stock Center fly cultures and that, unfortunately, we've sent 
contaminated samples to a few Stock Center users.  If you've received 
samples from us within the last three months, please be aware that 
they may have been contaminated.

The mites we found are common food mites (Tyrophagus 
putrescentiae).  This is not a species that produces hypopus larvae 
that cling to adult flies and it is not a predatory species.  The 
mites will, however, overwhelm cultures and outcompete flies for food 
if infestations are allowed to persist.

Full grown mites are about the length of a fly egg and will typically 
be found in and around fly pupal cases.  They eat the molds and fungi 
that grow in fly cultures.  They like to lay their eggs next to pupal 
cases.  Mite eggs are much smaller than fly eggs, but they have the 
same smooth, iridescent surface texture and are identical in 
color.  Usually, eggs will be seen before mites when scanning the 
walls of a culture vial.  Mite infestations will typically not be 
recognized until fly cultures are 3-4 weeks old.

Contaminated cultures may be cleaned up easily by rapid transfer of 
adult flies to fresh food.  We transfer adults to fresh food for four 
days in succession and discard the intermediate vials.  After rapid 
transfer, cleaned up vials should be grown for about a month to 
assure all mites were eliminated.  We have never found it necessary 
to use miticides such as Tedion.

We are taking steps to eliminate mites from our cultures, but it will 
be a long time before we are certain we have the problem under 
control.  You should continue to quarantine all stocks you receive 
from us and check them carefully.

We hope to get this mite outbreak under control quickly.

Thanks for your patience,
Kevin Cook
Kathy Matthews
Thom Kaufman
Luke Jacobus

__________________________________________________________
Kevin Cook, Ph.D.               Bloomington Drosophila Stock Center
Department of Biology           http://flystocks.bio.indiana.edu
Jordan Hall 142
Indiana University              812-856-1213
1001 E. Third St.               812-855-2577 (fax)
Bloomington, IN  47405-7005     kcook from bio.indiana.edu