Dragonflies, the beautiful and unique insect, have been known to fly long distances for survival and can anticipate their prey’s movement before pouncing. But one of the more curious things about dragonflies is how the female of the moorland hawkers dragonflies avoid sex from pushy males. The study, recently published in Ecology, described the female moorland hawkers faked death by crashing and lying still upside down. After a few moments, the male moorland hawker dragonflies lost interest and flew off to harass another female for sex.
The moorland hawker, or the common hawker or sedge darner dragonfly, is native to the Palearctic region (from Ireland to Japan) to northern North America. June to early October is consider their flight period. At almost three inches long, the moorland hawker has a brown body. The male of the species has a black abdomen with blue and yellow spots and narrow stripes along the thorax. The female moorland hawker has brown with yellow spots on the abdomen. They are usually found near bogs and ponds and have been seen at dusk.
Rassim Khelifa, a zoologist in the Department of Evolutionary Biology and Environmental Studies at the University of Zurich accidentally stumbled upon the behavior while in the Swiss Alps researching odonata eggs. Khelifa saw a dragonfly being chased by another when the insect being chased “suddenly crashed to the ground and lay motionless on its back,” the Tech Times reported. The other dragonfly then proceeded to hover over the crashed dragonfly before flying away. The “victim” was female, Khelifa noted, while the chaser was male. The female dragonfly surprised Khelifa when it took off. Afterward, he was intrigued and began observing other moorland hawker dragonflies who faked death to escape males.
Khelifa realized, after months of observation, that this was “common among females” of the moorland hawkers to faked death to avoid mating. Most other dragonfly species, Khelifa noted, usually protected females who were laying eggs. Another observation he made was the more male moorland hawker dragonflies were around, the more the females faked death. But, the Tech Times reported, their faked death was not always successful.
Newsweek said that Khelifa observed this unusual behavior for over two summers. The upside down position of the female moorland hawker dragonfly is an “atypical posture for a dragonfly.” While this behavior is rare within the animal, there are other examples: the robber fly, the European mantis, and a spider species. With the spider species, Pisaura mirabilis it is the male who fakes death to avoid “being killed after mating.” Phys.org reported this behavior as a survival technique. Some dragonfly species have the ability to pull sperm from previous males out of the female reproductive system and can cause damage.
By Cheryl Werber