We are having an annoying problem with collecting embryos.
Our Oregon-R stock does just great in bottles or vials, on
instant food, or on cornmeal-molasses-agar food, so we know that
they do like to mate and lay eggs. However, they refuse to lay
eggs on collection plates. We have tried various temperatures,
light/dark conditions, etc. We have tried grape juice plates
(recipe from Ashburners manual, with sucrose & yeast), orange
juice plates, and fly food (cornmeal-molasses-agar, i.e.
what they are used to living on) plates. We've tried using
mixed populations, and females only, large populations and small.
The one thing that helped a little (but not enough) was to use
a little bit of banana mash in the dollop of yeast paste on
the collection plate.
Does anyone have any idea of what is the problem? Since they
lay eggs just fine in the stock bottles, it would appear to
be a psychological problem, wouldn't it? (With the flies, although
we may need help soon, too.)
Thanks for any advice,
School of Biological Sciences
348 Manter Hall
University of Nebraska
Lincoln, NE 68588-0118
e-mail achristensen at unl.edu