Figure 4: Effect of torque application by a single anterior nectophore on whole-colony direction during swimming.
From: Multi-jet propulsion organized by clonal development in a colonial siphonophore
(a) Change in siphonophore colony orientation over two successive contractions of an anterior nectophore in a nine-member nectosome. The frame of reference was constant for all panels and contraction occurred in alternate panels (0.184, 0.512 s). Scale bar, 3 mm in length. (b) Change in position of the nectosome. Note that contraction by the anterior nectophore produced negligible vertical movement (linear regression, slope not significantly different than 0, P=0.48) while generating significant horizontal movement (y=18.4x−1.2, r2=0.99, P<0.001) and (c) altering the direction (∼50°) of the colony central nectosomal axis.
