Acknowledgements (for movies on pages 1 and 2) The GFP-talB-Cterm construct and the intermittent lighting device with its driver macro for NIH Image were made by Dr. K. Yoshida. Acrasis rosea was obtained from Dr. Robert Insall. Dictyostelium rosarium was from Dr. David Waddell. Dictyostelium lacteum was from Dr. John Bonner.