Whole body regeneration and developmental competition in two botryllid ascidians

Table 1 The potential of various body tissues (whole or partial) to develop into a feeding zooid

Tissues tested with vasculature	Open siphon (%)	N
None (Fig. 1C, D)	0	128
Partial primary bud (data not shown)	0	20
Secondary + partial primary bud (Fig. 4A, B)	89	82
Secondary bud (Fig. 4D, E)	48	27
Fragmented secondary bud (Additional file 14: Fig. S8A, B)	6	16
Secondary bud with reduced vasculature (≤ 3 mm²) (Fig. 5D)	0	10
Secondary bud with reduced vasculature (~ 6 mm²) (Fig. 5H)	25	4

Seven surgery permutations were performed on Botryllus schlosseri to determine how much tissue was required for a zooid to develop after injury, as assessed by the opening of siphons and feeding. The figures mentioned in column 1 are representative images for each surgery. Vascular tissue and tunic alone were insufficient to recover from loss of all zooids and associated buds. When only the anterior region of a primary bud was left to develop, it was resorbed into the existing tissue, but no zooid formation occurred. When a secondary bud was associated with that same portion of the primary bud, a zooid developed. Furthermore, secondary buds alone can complete development 48% of the time, but if damaged, survivability drops to only 6%. Secondary buds did not survive with less than 3 mm² tunic area after surgery; however, leaving an area of 6 mm² was sufficient to support full secondary bud development and asexual budding

ISSN: 2041-9139