Hemocytes undergo mitosis in the hemocoel. (A) Fluorescence overlay montage of perfused hemocytes from six-day-old mosquitoes showing all stages of mitosis. Mosquitoes had been treated with colchicine prior to perfusion, tubulin is stained green, and DNA is stained blue. (B) Fluorescence overlay of tubulin-stained (green) perfused cells from an E. coli-infected mosquito, showing differences in cytoskeletal arrangements. Note the crosshatched cytoskeleton in the granulocyte and smaller hemocyte and the rounded tubulin border in the ‘rounded’ hemocyte. The mitotic bodies and reordered cytoskeleton of a dividing granulocyte can be seen at center. Two fat body cells are also present and they contain larger nuclei and a more unstructured tubulin cytoskeleton when compared to a granolucyte. (C) Asymmetric mitosis of hemocytes resulting in one small daughter cell (bottom) and a granulocyte-sized daughter cell (top). (D) Fluorescence overlay montage of perfused hemocytes from mosquitoes infected with E. coli, showing that immune activated and phagocytic hemocytes can undergo mitosis. In this montage, tubulin is stained red, GFP-E. coli are green, and DNA is stained blue with Hoechst 33342.