Cover image

Cover: Ex vivo activation of an unfertilised mature Drosophila melanogaster egg initiates a propagating increase in intracellular calcium. This calcium “wave” starts at the posterior of the egg and moves towards the anterior. Longitudinal-section views at ten second intervals after activation are displayed as Calcium Green-1/Texas Red Dextran ratio images. Increasing Calcium concentration is shown from blue-green-red-white. In this issue, York-Andersen et al. describe how a calcium wave co-ordinates key developmental events in Drosophila egg activation. Photo credit: Richard M. Parton and Clare L. Bromley. See the article by York-Andersen et al. (doi: 10.1242/bio.201411296).