Mating wheel
The figure that dragonflies adopt during their mating is named as the mating wheel. The heart-shaped mating wheel comes about primarily due to the location of the genital organs. It can be observed with different types of dragonflies, especially in the summer in water.
The sexual and mating organs of dragonflies are in completely different places in the male and in the female. The males have the outlet ducts of the gonads on the ventral side of the 9th abdominal segment. However, they use a structure on the 2nd and 3rd abdominal segment as the mating organ. This consists of a cavity in the 2nd abdominal segment, which is usually provided with a clamp at the edge. The 3rd abdominal segment carries a seminal vesicle , which in the dragonflies ends in a "penis". This is equipped with a spoon-like structure at the top. The females also have the openings of their sexual organs on the 9th segment; these are mostly surrounded by parts of a laying apparatus ( ovipositor ).
Before mating, the male fills the seminal vesicle located in front with sperm by bending the abdomen. Sometimes it holds the female behind the head with its abdominal forceps ( cerci ), sometimes it only grabs it later (tandem formation). So held tight, the female tries to reach the male's mating organ with her sexual orifices and for this purpose curves her abdomen forward. The male's clamping device claws into the sexual opening of the female, and the spoon-shaped penis can be used to remove any remaining sperm from previous matings from the sexual opening. This creates the pairing wheel.
Depending on the type, this position can be maintained for between half a minute and several hours. It also persists in flight and the male often only lets go of the female when she has laid the eggs in a body of water.
photos
Mating wheel early Adonis dragonfly
Mating wheel horseshoe damsel
Pairing wheel, small blue arrow
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