EVOLUTION OF NEURAL DEVELOPMENT IN THE ARTHROPODS

Insects, both winged and wingless, possess a conserved set of neurons responsible for pioneering major axon pathways in the embryonic CNS an d the developmental program for generating those neurons appears to be similarly conserved. There is persuasive evidence that crustacean emb ryos possess homologues to at Least some of these neurons, although it is unclear whether processes of neurogenesis have been conserved betw een these two arthropod groups. Myriapods, which are traditionally hel d to be a sister group to the insects, have a pattern of neuronal deve lopment which shows many differences to the insect/crustacean plan. I discuss how developmental processes have been altered during evolution to produce differences in neural organization seen both within and be tween major arthropod groups.