In Nasonia , the fertilized egg gives rise to an embryo that undergoes syncytial and cellular blastoderm stages morphologically similar to those of Drosophila. Both Nasonia and Drosophila undergo the long germband mode of embryonic development. Despite these similarities, two observations suggest that the relative importance of maternal versus zygotic patterning functions may differ in the two insects. This difference in timing may allow for greater zygotic control of patterning in Nasonia than in Drosophila. Among the relatives of Nasonia , a polyembryonic mode of development has evolved in which a single fertilized egg gives rise to hundreds or thousands of progeny.
Polyembryonic development is likely to rely heavily on zygotic control of patterning.
Polyembryony has arisen several times in the Hymenoptera, and the polyembryonic Copidosoma floridanum is in the same superfamily as Nasonia . This question may be approached genetically, by isolating zygotic mutations that disrupt early anteroposterior patterning in Nasonia . The terminal structures deleted in torso embryos are anterior to the gnathal segments and posterior to the seventh abdominal segment, and are thus limited compared to those of the zygotic squiggy mutant embryos. The extensive zygotic control of terminal development by squiggy appears to be a departure from Drosophila developmental mechanisms. The Drosophila maternal terminal gene patterning system is not known to be widely conserved, and the follicle cell types that express torsolike do not appear to be conserved even in the lower Diptera.