Increased production of genetic mosaics in Habrobracon juglandis by cold shock of newly oviposited eggs.

Eggs from an ebony stock exposed to 5-5 degrees C prior to syngamy exhibited increased production of genetic mosaics in comparison with untreated eggs from the same females. No increase in mosaic production occurred for cold-shocked cleavage-stage embryos from the ebony stock or from pre-cleavage cold-shocked eggs from a wild-type stock. Heat shock of pre-syngamy eggs also failed to increase the production of genetic mosaics. These findings are consistent with predictions based on the post-cleavage fertilization theory of mosaic origin in Habrobracon or with a hypothesis of differential mortality.