causes cleavage furrow regression in crane-fly and Drosophila spermatocytes. (A, B) Time-lapse phase-contrast micrographs showing ET-18-OCH3-treated dividing (A) crane-fly or (B) Drosophila spermatocytes [see Additional files 5, 6]. For each cell, 35 μM ET-18-OCH3 was added just after the time-point depicted in the second panel. Bars, 10 μm. (C) Plot of the change in cell diameter (ordinate) over time (abscissa) for the crane-fly (+) and Drosophila (o) spermatocytes shown in A, B. Arrows indicate time of drug addition. (D). Sensitivity of Drosophila spermatocyte cytokinesis to increasing concentrations of ET-18-OCH3. Cytokinesis failed in the majority of cells treated with 30 μM and in all cells treated with 35–40 μM ET-18-OCH3.