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Cremlingen, Germany

Gunther A.,TU Bergakademie Freiberg | Hilfert-Ruppell D.,TU Braunschweig | Ruppell G.,An der Wasserfurche 32
International Journal of Odonatology | Year: 2014

The reproductive behaviour of the damselfly Neurobasis chinensis (Calopterygidae) was filmed at 300 and 600 frames per second in Thailand in spring 2009. This was subsequently viewed in slow motion for detailed analysis. Altogether we observed 26 matings at two different sites. Besides visual observations of behaviour of male-female encounters at the reproductive sites, we analysed their flight cinematographically by measuring velocity, wing beat frequency, phase relationships of fore- and hind wings, and described the flight paths of different flight manoeuvres. Wing clapping by the perched insects was analysed in detail. Also filmed were alternative reproductive behaviour and avoidance behaviour when attacked by a hunting spider. By analysing the video footage in slow motion, details of male flight with hind wings held motionless, a typical flight-style for this genus, were revealed. The significance of this behaviour in interactions with conspecifics is discussed. © 2014 © 2014 Worldwide Dragonfly Association. Source


Ruppell G.,An der Wasserfurche 32 | Hilfert-Ruppell D.,TU Braunschweig
International Journal of Odonatology | Year: 2013

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. © 2013 Copyright Worldwide Dragonfly Association. Source


Hilfert-Ruppell D.,TU Braunschweig | Ruppell G.,An der Wasserfurche 32
International Journal of Odonatology | Year: 2013

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. © 2013 Worldwide Dragonfly Association. Source


Ruppell G.,An der Wasserfurche 32 | Hilfert-Ruppell D.,TU Braunschweig
International Journal of Odonatology | Year: 2010

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. Source


Ruppell G.,An der Wasserfurche 32 | Hilfert-Ruppell D.,TU Braunschweig
International Journal of Odonatology | Year: 2014

By means of slow-motion film analysis we found new female refusal behaviour patterns against male harassment in a variety of Odonata species. Often, females could escape simply by flying faster than males. Due to the morphological preconditions, there were differences in the two suborders. In Anisoptera, several behavioural specialities were analysed: (a) females of Aeshna cyanea, which oviposit solitarily and endophytically, clung to the substrate with great force when being pulled away by attacking males. (b) Anax imperator females showed a very fast, characteristic bending of the abdomen causing sudden U-turns for escape. (c) Solitary Libellula quadrimaculata females flew loops to escape pursuing males or to shake them off. They either used the impact of the crashing male for the turning moment or they generated it themselves by an abrupt change of the wing beat direction. In Zygoptera we investigated different Calopteryx species, which all oviposit alone. Fleeing was most common but wing clapping, not cooperating to build a tandem, tandem separation, fast diving for submerged oviposition and threatening and attacking the male were also documented. Fast water current prevented submerged oviposition by Calopteryx xanthostoma and increased refusal behaviour by females. © 2014, © 2014 Worldwide Dragonfly Association. Source

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