Chemosensors and ovipositing

William J. Etges wetges at COMP.UARK.EDU
Fri Mar 15 09:48:44 EST 1996

>I'm sure that there are more experienced people who can tell you better,
>but in general getting eggs on demand is a pain in the neck. I don't
>know if anybody has isolated specific chemical cues, but they respond
>mostly to presence of appropriately appealing food. There are several
>egg laying medium described in Ashburner's Drosophila Lab Handbook. I
>just use Carolina's instant blue medium reconstituted with grape juice
>with a layer of yeast paste. They tend to lay mostly during dusk hours
>which you can manipulate with lighting conditions. And they will also
>tend to lay eggs on demand if they have been food stressed (try starving
>them overnight and then present them with food). However, some species
>just won't lay 'em no matter what you do. (I'm having horrible time with
>hydei spp.) OTOH, simulans spp. seems ready to lay eggs at anytime.
>Junhyong Kim

The "problem" you refer to with D. hydei and some related repleta group
species is due to the fact that they are cyclical egg layers.  Females in
some species tend to cycle regularly due to hormonal regulation.  For
starters, see:
Kambysellis, MP 1968 Univ. Tex. Publ. 6818:71-92
Etges, WJ and WB Heed 1992  Heredity 68:515-528.

        There are many reasons, genetic and environmental, why female
Drosophila tend to oviposit in certain conditions.


William J. Etges
Department of Biological Sciences
SCEN 629
University of Arkansas
Fayetteville, AR 72701  USA
wetges at
voice: (501) 575-6358
FAX   (501) 575-4010

"Work hard and don't make excuses."
         Annette Peters, U.S. Distance Runner.

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