"Alien" wasps and evolution of development

A comparative analysis of early developmental programs in a group of parasi tic wasps reveals that closely related species can undergo dramatic evoluti onary shifts in their patterns of embryogenesis. Developmental changes dete cted include alterations in early cleavage divisions, the establishment of embryonic anteroposterior polarity and modifications of the segmentation ge ne hierarchy described from Drosophila. These changes appear to be adaptati ons to parasitic development, taking place within the body of the host. Was ps illustrate a surprising plasticity in their early development and embryo genesis. The alterations associated with different parasitic strategies sug gest that ecological adaptations may have profound influences on developmen tal processes in animals. (C) 2000 John Wiley & Sons, Inc.