Dragonflies are master predators. Whether it be as they swim beneath the water or flit above our heads, they are perfectly adapted to hunt and eat. Unfortunately for them however, they aren’t the only ones looking for a tasty snack, and all kinds of animals enjoy a dragonfly on the go every now and then.
We may not think of fish and dragonflies as sharing the same world, but in fact, dragonflies spend most of their lives beneath the water. As larvae, they live within ponds, streams and even lakes, swimming slowly through the murky water, looking for prey.
Many will go to great lengths to avoid being seen by fish, hiding in the mud or water weeds, and camouflaging themselves in shades of green and brown. In artificial pools, unnaturally high numbers of fish, and lack of places to hide, can quickly mean that there are no dragonfly larvae at all.
Even as adults, fish are things to be feared. Though dragonflies spend a great deal of time flying through the air, they often rest on lilypads or vegetation near the water. They may even swoop down to the water to drink. At these times, it’s easy for a fish to emerge from beneath the water’s surface and gulp down the unsuspecting insects.
One ritual that particularly endangers the dragonfly is the mating ritual. Different species lay their eggs in different locations, but some lay directly into the water. Often the males will hold onto the females and dip them into the water to lay their eggs. This could result in a fish swiftly grabbing the female and potentially dragging them both down.
Just like fish, amphibian species can eat dragonflies both in and out of the water. Most amphibians, such as newts, frogs and toads, will happily hunt both above the water and below. Within the water, aquatic invertebrates are excellent fodder. Dragonfly larvae aren’t the fastest swimmers, but they can expel water from their anus in order to propel themselves to safety.
Above the water, it takes a bit of luck for an amphibian to catch a dragonfly. They may be able to grab one as it undergoes the transformation from larvae to adult, a period when it is particularly vulnerable and unable to move. Or it may be able to use camouflage to creep up on a resting dragonfly and snap a tasty snack.
When it comes to dragonfly larvae, they are very much fair game to any wading or water birds that come across them. Many ducks or waders eat aquatic invertebrates. So while they may not specifically focus on dragonfly larvae, they will undoubtedly be a welcome addition when found.
Dragonflies tend to emerge in large numbers around the same time. This is because the period when they are transforming from larvae to an adult is one where they are particularly vulnerable. As they emerge from their larval skin, they cannot move until their new exoskeleton has hardened. Even once it has, their first flight is often weak and problematic. This is the perfect time for birds like robins, crows and magpies to grab them. By emerging in large numbers, there will always be some that getaway.
However, once the adult has found their wings, few birds are fast and agile enough to catch them. One expert in catching dragonflies is the hobby. This bird of prey, with its sickle-shaped wings, is extraordinarily fast. Zipping through the air it can capture one after the other of the tiny invertebrates, often eating them on the wing.
As with many insects, the rule on who eats who generally revolves around who is the biggest. Under the water, dragonfly larvae will even predate each other if they come across a smaller, weaker cousin.
Out of the water, dragonflies are most likely to fall prey to other insects when they undergo their transformation from larvae to an adult. While their exoskeleton and their wings are still soft, they cannot defend themselves or fly away. If found by a hungry wasp, or a group of ants, they can do nothing about their slow and miserable demise.
We don’t often think of plants as eating meat. However, there are a wide variety of plants that do just this. Many specialise in attracting in flies through producing attractive smelling or tasting liquids, but some simply catch what they can.
The sundews are a group of plants that use sticky droplets on their leaves to capture insects when they land on them. They grow in bogs, wet areas that have acidic peaty soils. These areas are also significant for dragonflies because there are often pools and streams, and few fish can live there due to the slightly acidic water conditions.
While larger dragonflies may well be able to escape the sticky trap of the sundew, many smaller ones struggle in vain, and in time the plant will curl its leaf around it and digest the still-living insect.
Making homes for dragonflies
Dragonflies are not only wonderful to watch, but they also help control many annoying pests, such as flies and wasps. They are also an important food source for some species, particularly in their larval stage.
The most important thing for dragonflies is to provide water, ideally a pond without fish in it. Provide plenty of aquatic plants for them to hide in, as well as edge vegetation so they can emerge in safety. It’s also beneficial to plant up around the pond, so it isn’t easy for them to be picked off once they take their maiden flight.