Backswimmer Facts & Information (Notonectidae)

As previously mentioned, backswimmers are commonly mistaken for water boatmen. Both aquatic insects are slender and ovoid. They also both have large and powerful back legs. Luckily, if you know what you are looking for, correctly identifying them is relatively straightforward.

One of the first things to pay attention to is location. Backswimmers are commonly found in artificial water sources like pools, fountains, and bird baths. In contrast, water boatmen are rarely found in artificial sources and prefer natural, slow-moving waters like deep, still creeks, ponds, lakes, and lazy rivers. The back of a backswimmer is keeled which this helps backswimmers swim in their characteristic upside-down position. While water boatmen have narrow, parallel lines on their backside, backswimmers do not have this feature.

Backswimmers are usually found in ponds, quiet lakes, and slow-moving streams. They are hardy insects that can thrive in habitats that provide them with lots of vegetation, as they will utilize plants for cover so they can ambush prey. Backswimmers are even capable of surviving under the ice in freezing conditions!

In the winter, when temperatures drop, some backswimmer species will hibernate at the bottom of their lake or pond habitat when it freezes. Others will remain active, using their scuba-like adaptation to breathe under frozen waters and hunt for prey.

Sources have described backswimmers as “voracious predators.” They tend to eat anything of a suitable size that they can catch. Backswimmers feed on various prey species, such as other aquatic insects, tadpoles, and even small fish. Surprisingly, they are also known to prey on other members of the same species. Backswimmers are known as “piercer-predators,” meaning they have a distinct method of killing and consuming their prey. First, they use their strong, sharp beak to pierce into unsuspecting prey. Once the backswimmer pierces its victim, it injects digestive enzymes into the prey’s body cavity, which paralyze the prey item and dissolve its insides. The backswimmer will then suck the bodily fluids out of the insect using its mouthparts.

To catch a meal, the backswimmer will dive beneath the water’s surface and ambush submerged prey. Additionally, backswimmers may lurk amongst submerged vegetation and wait for a prey item to swim by. Finally, if the backswimmer is hanging out in the bottom vegetation, it can release its grasp and float upwards to catch prey higher up in the water column.

While backswimmers are aggressive predators, they are by no means at the top of the food chain. Many fish, insects, and amphibians see these insects as excellent meals.

This is not recommended, but another way to tell the difference between these two aquatic bugs is to get bit. If the insect in question bites you and feels like a bee sting, you know you have a backswimmer on your hands. Water boatmen are harmless to humans and do not bite or sting. However, backswimmers inflict a sharp and painful bite, comparable to the feeling of a bee sting. Because they are known to bite people swimming in the water, they are often referred to as “water wasps.”

Although they bite and emit a toxin that helps immobilize and digest their prey, backswimmers do not pose a serious threat to humans. In other words, their bites are painful but do not cause any lasting harm. Backswimmers don’t bite humans unless they feel threatened, such as when they are picked up. In addition, they typically swim away from you, so you should not get bit if you refrain from handling them.

Like all other “true bugs,” backswimmers experience an incomplete metamorphosis known as hemimetaboly. During this process, they experience gradual developmental changes from egg to adult form. There are three stages: egg, nymph, and adult. Nymphal stages are similar to each other, and the development of wings marks the adult stage.

During the spring and summertime mating season, a male will rub his front legs against his rostrum or mouthparts, to make a unique sound and hopefully impress a mate. This process is known as “stridulation.” This is a similar method used by crickets when they rub their wings together to “chirp.” Backswimmers complete their life cycle in approximately six months, producing two generations per year.

If the male successfully attracts a mate, the pair will undergo a mating ritual. The female will then deposit her eggs on aquatic vegetation. She may also use a rock to lay her eggs on if there is no vegetation available. The eggs are usually clumped in groups of 10. Within a few weeks, the eggs hatch, and backswimmer nymphs will emerge. The spirits have white-colored bodies and red eyes.

When a backswimmer reaches the adult stage, it is nearing the end of its life and most backswimmers die soon after mating.

Backswimmers can be beneficial in your backyard pond because they help control the populations of other aquatic insects and are an excellent food source for many fish and wildlife species. However, they can inflict a painful bite on humans, so be wary if you see some in your pond.

Although backswimmers can bite humans when threatened, they are still more beneficial than they are harmful. For example, they feed on mosquito larvae, so if you live in humid environment that is conducive to mosquito propagation, they may help reduce mosquito numbers in your area.

It is certainly possible to attract backswimmers to your pond and there are few things you can do to achieve this. They are primarily attracted to stagnant water with abundant food sources. If you have some lights that turn on at night, place them by the edge of your backyard pond, or install some underwater pond lights, and backswimmers will be attracted to the new habitat. This will also attract water boatmen.