SEGMENTATION (AND EVE) IN VERY ODD INSECT EMBRYOS

The formation of segments in the Drosophila early embryo is understood in greater detail than any other complex developmental process. Now, by studying other types of insect embryo, we can hope to deduce someth ing of the ancestral mechanism of segmentation and the ways in which i t has been modified in evolution. The parasitic wasp, Copidosoma flori danum, is spectacularly atypical of insects in that the small egg cell divides extensively, with no initial syncytial phase, and forms event ually some 2000 embryos((1)). This process raises intriguing questions about the control of embryonic polarity and segmentation.