Fig. 6

Three post-surgery secondary buds lead to a single zooid through competition in Botryllus schlosseri. A Illustration showing surgery performed to remove zooids, primary buds, and all but three secondary buds (yellow, white arrows). B Darkfield image of post-surgery. Secondary buds are indicated (white dashed circles). C Seven days post-surgery. All three secondary buds (white arrows) have pumping hearts. Higher magnification of each bud is shown in D–F along with associated bud # (b1, b2, b3). D Bud from left side of C (b1). E Bud from top of C (b2). F Bud from right side of C (b3). G The single zooid that fully developed is shown magnified in G (b4, formerly b3). H Colony at day 13 showing single zooid (b4, white arrow) had open siphons. Two other buds were in the process of resorption. dps days post-surgery. Scale bars = 0.5 mm