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, 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