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.
