Dragonflies—Consummate Aerial Predator

Birds of prey, such as hawks, eagles, and owls, have a success rate in the low twenty percent range when attacking a selected prey animal. Dragonflies, insects of the order Odonata, succeed in taking their prey by midair attack around 95% of the time, making them the most successful predator on planet Earth. They are one of the oldest groups of insects, with nearly-identical (but sometimes much larger) specimens found in fossils older than 325 million years. When something works, nature stays with it.

The body plan of dragonflies differs substantially from most other flying insects. The wings do not fold, but stay extended from the body, and are actuated by separate muscles not coupled to the thorax, which allow each of the four wings to move independently and enables hovering, fast dashes up to 50 km/hour (the fastest flying insect), and even flying backward. This allows them to intercept their prey, predicting its trajectory, tracking with their movable head, and plotting an intercepting course.

Giant dragonflies are found in the fossil record, with Meganeuropsis permiana which lived around 290 million years ago, estimated as having a wingspan of 70 cm. It is believed the giant species died out due to the oxygen content of Earth’s atmosphere falling over time, and possibly due to competition from flying dinosaurs and early birds.

Here is a photo essay from Animal Magnetism on Big Green, the giant dragonfly (Aeshna cyanea) that patrols Fourmilac in the summer.



i found this on the internet so it must be true:

A dragonfly is able to lift about 10 times its own body weight. This means that a dragonfly can lift a weight that is equal to the weight of 10 dragonflies. The weight that a dragonfly can lift is also dependent on the size of the dragonfly. The larger the dragonfly, the more weight it can lift.
A dragonfly’s lifting ability is due to the fact that it has two pairs of wings that are attached to its body. The wings are what give the dragonfly its lifting power. The wings are also what allow the dragonfly to fly so fast and so gracefully… The body weight of a typical dragonfly ranges from 600 milligrams to 1 gram.

So if “Big Green” had a 10cm span and weighed just 1 gram, the 70cm giant would weigh 343g because mass follows volume and volume goes up as the cube of length. The 10:1 load rating would yield a 3kg payload. But something makes me think the payload does not scale that well due to strength of materials issues, etc. But still able to pick up a moderate size rodent…