If I ask you to picture the world's deadliest hunter, you probably conjure an image of a mighty lion or a fearsome shark, but the king of the jungle only has a predatory success rate of 25%. The great white shark has a more impressive success rate of around 80%, but this still pales compared to an unlikely hunter.
The dragonfly is one of nature's greatest hunters, with a capture success rate of up to 97%! These tiny insects may look delicate, but they are one of the world's strongest bugs whose impressive skills make them the most successful hunter on Earth. Here's why.
Dragonflies are one of the fastest flying insects in the world, traveling at speeds of up to 35 miles per hour. And it's not just their movements that are quick; their reaction times are super speedy too.
When a dragonfly decides to attack, it can pounce on its prey within 50 milliseconds. We may use the phrase "in the blink of an eye" to describe something that happens quickly, but human blinking takes around 300 milliseconds (six times as long as it takes a dragonfly to launch an attack on its prey).
In addition, quick head movements and 360-degree eyes allow the dragonfly to keep their eyes on the target and detect any subtle movements their prey makes. And specialized neurons detect the target's motion before instructing the dragonfly's wings to react.
Masters of Prediction
These winged insects don't rely on speed alone to catch their prey; they also use the power of prediction to anticipate the insect's flight path. Once a dragonfly locates suitable prey, they watch its movements while adjusting their flight path. Some scientists liken this ability to a ballet dancer catching his partner. It takes the same calculations of sense and motion to execute and is the first example of this skill within the invertebrate kingdom.
One particular neuron known as the Centrifugal Small Target Motion Detector 1 - or CSTMD1 - demonstrates two remarkable properties considering the size of the dragonfly's brain. The first is prediction; when a target moves into a dragonfly's visual field, specific neurons can "encode" the area around the target, creating both enhanced and suppressed activity regions.
The second property of these impressive neurons is selective attention. This allows the dragonfly to stalk prey successfully within various distracting environments - such as busy riverbanks - and focus on one target rather than being distracted by other insects or moving objects.
Another factor that makes the dragonfly a successful predator is its air-based abilities. These nifty creatures can fly forward, backward, and upside down, dive, hover, and turn a 360-degree circle in just three wingbeats.
Dragonflies possess four transparent and flexible wings attached to the thorax by separate muscles, allowing each to move independently. And this body modification will enable them to move in any direction or angle.
In contrast to many insects that rely on smell and touch to capture their prey, the dragonfly depends almost entirely on sight. Practically the entire head is covered by two large compound eyes, which provide a dragonfly with an almost entire field of vision (the only area they can't see is directly behind their head).
These two complex eyes are filled with thousands of lenses and form the base of a dragonfly's sense of sight, along with three smaller, less complex eyes. And dragonfly eyes contain four or five unique opsins allowing them to view colors beyond human capabilities, such as ultraviolet light.
Each eye has segregated areas that are sensitive to different colors. For example, the upward-facing eye has only UV and blue receptors, providing a unique hunting advantage. The concentrated opsins mean that the sky appears exceptionally bright to a dragonfly, allowing them to distinguish insects more easily. This color separation lets the dragonfly view objects against prominent backgrounds, simplifying prey detection.
The dragonfly has to be a successful hunter because it has a large appetite and can eat its own body weight in food every day.
Dragonflies cannot "walk," so they catch most of their prey in mid-air without stopping. They have two main methods for doing this; one is to create a kind of "basket" with their legs and scoop up the prey as they pass; the other is to open their mouth and catch the food as they fly past. Still, some dragonflies prefer to glean prey by catching insects perched above plant stems, while immature adults eat the caterpillars hanging from trees.