The maiden flight of five species of Odonata of different families was filmed by slow motion up to 500 f/ s and analysed frame by frame. The aim of this study was to find out if the maiden flight differs among various species as well as between tenerals and adults within the same species with respect to wing beat frequency, phase-relationship between fore-and hind wings, flight speed and acceleration. All the values of the flight parameters were much lower in maiden flight than in the flight of adults. The possible reasons for the weakness of the maiden flight are discussed.

By analysis of slow-motion films of dragonflies and damselflies in free flight, released in front of a backdrop or startled during flight, the following flight parameters have been quantified for symmetrical manoeuvres: wingbeat frequency, relative durations of up- and downstroke, phase relationships of the beats of fore- and hindwings, stroke amplitude, mean stroke velocity, flight velocity, nondimensional flight velocity, advance ratio, acceleration, angle of attack and stroke plane. The wingbeat frequencies are higher in the smaller species and in those with relatively large wing loading. As a rule, Zygoptera have a wingbeat frequency only half that of Anisoptera. The stroke amplitude is almost always much larger in Zygoptera than in Anisoptera, which have a greater range of variation in this respect. Stroke velocity is higher in Anisoptera than in Zygoptera; it is also higher in the more elaborate flight manoeuvres than in others. The calculated stroke velocities resemble those actually measured. Anisoptera fly more rapidly than Zygoptera. With respect to the nondimensional flight velocities, it is notable that although the values for Anisoptera are higher than those for Zygoptera, they are exceeded by the Calopterygidae; the latter can fold their wings back during rapid forward flight and shoot away, as in the ‘ballistic’ flight of small songbirds. However, the advance ratio is higher in Anisoptera than in Calopterygidae. Anisoptera also perform better than Zygoptera with respect to acceleration. Three categories of phase relationships between the beats of the fore- and hindwings are established: counterstroking, phase-shifted stroking and parallel stroking. Counterstroking produces uniform flight, whereas the flight produced by phase-shifted and, in particular, parallel stroking is irregular. The angles of attack of the wings are shown to be associated with particular flight manoeuvres, as are the stroke planes. Flight manoeuvres are discussed without drawing detailed aerodynamic conclusions. The flight of Anisoptera is compared with that of Zygoptera.

Slow motion films of fight behaviour of five different species of Odonata were analysed. In all cases biting played a major role. The biting duration depended on the duration of a stable connection between the two opponents. Sitting odonates showed much longer biting than those that were flying. In fights of Anax junius and Calopteryx splendens long biting between males led to serious injuries and death. Two males of Anax imperator bit each other by very short strikes during looping flights together, better described as hack-biting. This hack-biting was seen in two other fights: a female of Libellula quadrimaculata bit a harassing male on the head, immobilizing him, and during a male-male fight in C. splendens flying nearly on the spot. Loops, very brief but relatively stable flight positions, were used for biting in three cases. The significance of biting in inter-and intrasexual competition in Odonata is discussed.

The flights of male odonates encountering conspecifics at their reproduction sites were investigated by means of slow-motion films. We recorded large and generally consistent differences between species with clear wings (SCLW) and species with coloured wings (SCOW). SCLW mostly fought having physical contact and moved their wings without pauses in wing beats (hereafter designated wing pauses), attacking the other males. During encounters, SCOW males showed pauses of all wings or of the fore or the hind wings only. The wing beat frequencies of SCOW therefore showed much greater variation than in SCLW. In Zygoptera SCOW, parallel flapping of both wing pairs was frequent. The two investigated species of Calopterygidae showed several special flight patterns when encountering other males. Male Anisoptera with coloured wings also used wing pauses, and often displayed their wing patterns by gliding and banking to the other male or by flying in an upright posture. Thus, we found that most odonate males with coloured wings, in the presence of rivals, exhibited special flight styles, implying signalling functions. We interpret wing pauses as an adaptive characteristic that allows rival males to evaluate the quality of their opponent by assessment of the coloured wings. Sexual selection is suggested as a possible cause for the evolution of these flights.