Females carrying two copies of thr^{RD.T:Hsap\MYC} are fertile at 25^oC, but almost completely sterile at 18^oC. At 18^oC, many eggs are laid but very few larvae hatch. 19% of syncytial embryos derived from females carrying two copies of thr^{RD.T:Hsap\MYC} and raised at 18^oC during early development have various irregularities, which include embryonic regions with mitotic asynchrony, abnormal mitotic figures and lower nuclear densities than normal. Many embryos with regular nuclear distribution have fewer nuclei compared to control embryos of the same age. During cellularisation 98% of embryos derived from females carrying two copies of thr^{RD.T:Hsap\MYC} and raised at 18^oC during early development lose a large fraction of nuclei from the egg periphery (the nuclei accumulate in the yolk region in the interior of the egg).