Evidence for post-cleavage fertilization among mosaics in Habrobracon juglandis.

Habrobracon females homozygous for the mutant ebony produce about 5% mosaic progeny among fertilized eggs. The present experiment demonstrates by means of a test-cross method that in the production of these mosaics only one pronucleus is involved, and that this nucleus cleaves before union of one of its daughter nuclei with the sperm nucleus.