Responses of Bugula neritina, an arborescent bryozoan to the removal of growing tips: short term patterns of regeneration.

In colonial organisms, physical damage or predation can result in the loss of part of the colony. Although the colony may survive, the loss of part of the colony may alter patterns of growth and reproduction. In this study, the response of Bugula neritina, an arborescent bryozoan, to physical damage was tested in three experiments: 1) short term regenerative responses to the removal of zooids from growth tips; ii) growth and reproductive responses to damage imposed at different locations within the colony; and iii) the effects of damage produced by a natural predator, the nudibranch Polycera hedgepethi. This dataset gives the growth response of immature colonies over two weeks following the removal of zooids from growth tips of branches from one side of a colony; the remaining side of the colony was left intact. Immature colonies which had undergone four branching events were used in the experiment. After damage was imposed, colonies were returned to the field site at Williamstown, Victoria. Colony size (branching score) and the proportion of branches with budding tips were measured on damaged and intact sides of each colony for three weeks between January and February 2000. Branch tips resumed budding within a few days of damage being imposed and the proportion of budding tips on the damaged sides of the colonies did not differ from intact sides after two weeks. Damaged sides of colonies were smaller than intact sides two weeks after injury but growth rates were similar by day seven.