A research team from Hughes Medical Institute in Ashburn, Virginia, had the curiosity of learning more about dragonflies’ hunting methods. By using ultra-high-speed cameras and an artificial fruit fly to lure the dragonfly into hunting it, researchers learned that dragonflies use a predictive way of hunting not a reactive one. This means that they have their own strategies when approaching their prey and don’t just copy their victims’ movements.
To this day, scientists believed that only mammals, fish and birds used predictive hunting techniques, not insects. Also, they believed that dragonflies just fly blindly after their prey (bees and flies) and mimic all their steering movements until they are able to catch up with them.
The recent experiment proved the scientists were wrong. It seems that dragonflies have a unique hunting strategy. Actually, these predatory insects are very sneaky when hunting – they camouflage their movements and body orientation but they do not lose sight of their food.
Researchers said that if these insects used reactive hunting methods, each steering movement from their kill would have been perfectly copied by the dragonflies. But, when the fruit flies changed their flight direction, the dragonflies did not and stayed on their original course 70 percent of the time.
Also, scientists say that during the hunt dragonflies take their time to plot an original path for interception since three quarters of their steering movements were different from their prey’s flight deviations.
Researcher Anthony Leonardo said that the dragonfly lines up his body in the flight direction of the prey, but it locks on to its target visually. By doing so, the dragonfly is able to snatch the prey from beneath and behind, two of the prey’s blind spots.
Researchers found that even when the prey suddenly changes direction, the dragonflies don’t go into reactive movement – they just fix their eyes on the target and carry on with their predictive steering manoeuvres.
The research team used tiny reflectors pointing to the heads and backs of the dragonflies that allowed the very fast motion cameras to capture every single movement of the insects while on a hunt. As prey, scientists used fruit-flies-shaped 2 mm beads that were remote guided by a computer.
The dragonflies were tested several times. Each time, researchers used a launch pad surrounded by artificial vegetation that would make the insects think they were in their natural habitat.
Soon, Leonardo and his colleagues plan to analyze how dragonflies’ neurons get involved into the hunting process, and how they send the proper signals to muscles to help these insects suddenly change flight direction.