Fig. 9. Starting manoeuvres in Enallagma cyathigerum larva. (A) Start of normal swimming sequence. On the right is a series of body profiles at 40 ms intervals together with a scheme of the body and tail flows which contribute to the first full-sized vortex (V2) in the swimming sequence. The path followed by the fin tip (filled circle) during the corresponding stages is shown on the left. A small vortex (V1) is usually produced during the second half-stroke, but the first full-sized vortex is produced on the third half-stroke from the beginning of the manoeuvre. Note that the larva moves off on a heading parallel with the original orientation of the body. (B,C) Successive profiles, at 40 ms intervals, during two rapid-flex manoeuvres, one resulting in a turn of 30° (B) and the other 160° (C) away from the original heading of the body. In each case, the larva was reacting to a stimulus (light touch) from the right-hand side. As a result of a rapid flex away from this side followed by a rapid straightening of the body, a thrust jet is produced on the right-hand side, the direction of which is approximately opposite to the line of travel of the body out of the turn.
