How do bryozoans reproduce by budding?

Bryozoans reproduce asexually through a process called budding, which allows them to form colonies composed of numerous connected units known as zooids. This process typically begins from a primary zooid, called an ancestrula, which originates from a sexually produced larva, or from a dormant bud known as a statoblast.12

The specific mechanics of budding vary by class:

• Phylactolaemates: New zooids bud from the ancestrula, often resulting in branched colonies. New polypides (the internal feeding structures) originate from the ingrowth of the epithelium.2
• Stenolaemates: A larva metamorphoses into a primary disk, from which a cylindrical extension grows. The colony matrix is then built through repeated divisions of the zooidal walls, with growth occurring at the outer edges.2
• Gymnolaemates: Budding often occurs as transverse septa form to cut off parts of a parent zooid. In the order Cheilostomata, this process produces radiating rows of identical zooids that divide to accommodate the colony's increasing circumference.2

As each bud enlarges, a new polypide forms inside, ensuring the colony continues to expand.2