The kinematics of six species of Heteroptera in free flight are analysed and compared.
- 1Using nested analysis of variance techniques, statistically significant variation was detected between species for several of the flight parameters measured: mean angular velocity; pronation/supination ratio; upstroke/downstroke ratio; and wing beat frequency. In each case this is discussed in terms of variation in flight behaviour.
- 2Beneficial aerodynamic forces are generated during the upstroke and the downstroke, in both fast forward and rising flight.
- 3When the insects change from level, forward flight to near vertical, rising flight, the following parameters are altered in most of the sequences analysed:
- (a). the stroke plane angle becomes steeply, negatively inclined, associated with an increase in body angle;
- (b). the stroke amplitude is reduced;
- (c). wing beat frequency is lowered, associated with a drop in mean angular velocity;
- (d). the speed of stroke reversal (rotational velocity) is increased. This may be associated with increased wing torsion and tip flexion which in turn could improve any beneficial unsteady aerodynamic effects generated at stroke reversal.
The reasons for this change in flight performance and the deviations from that seen in other insects are discussed.
It is shown that Heteroptera may make use of wing drag in flight, particularly during rising flight.