What is Backswimmer?
Backswimmer, (belonging to the family Notonectidae), any of a genus of insects (order Heteroptera) known for their ability to swim on their backs, which resemble the keel and sides of a boat. The backswimmer propels itself with its long oar-like legs and has an oval-shaped head and an elongated body that is generally less than 15 mm (0.6 inches) in length. It is a good example of countershading because its light-coloured back blends into the water surface and sky when viewed from below. The rest of the body is darker and blends in with the bottom of the body of water in which it lives when viewed from above.
The backswimmer rises to the surface after releasing its grip on the bottom vegetation because it is lighter than water. When it reaches the surface, it can either fly or get a fresh supply of air, which is stored in a bubble under its wings and around its body, and dive again. Backswimmers are frequently seen floating on the water's surface with their legs extended, ready to dart away if disturbed. It feeds on insects, small tadpoles, and fish, sucking their bodily fluids with its powerful beak.
The genus Notonecta, which is found all over the world, has the potential to be extremely harmful to fish and tadpoles. When handled, it will bite humans, the bite feeling similar to a bee sting. It lays its eggs on or in the plant tissue of pond vegetation. During the winter, the grousewinged backswimmer, N. undulata, can be seen swimming beneath the ice in North America.
Because of the pigment (haemoglobin) contained in certain cells, the genus Buenoa, which usually floats or swims some distance below the surface, appears reddish or pinkish in colour.
Description of Backswimmers
A backswimmer is designed in the shape of an upside-down boat. The dorsal side of a backswimmer is convex and V-shaped, similar to a boat's keel. These aquatic insects propel themselves across the water by using their long back legs as oars. Rowing legs do not have claws but are fringed with long hairs. The colouration of the backswimmer is the polar opposite of that of most insects, owing to the fact that they live their lives upside down. A backswimmer is distinguished by a dark belly and a light back. As they backstroke around the pond, they are less visible to predators.
The head of a backswimmer is typical of an aquatic true bug. It has two large, close-together eyes but no ocelli. The beak (or rostrum) is cylindrical and folds neatly under the head. The short antennae, with only three to four segments, are almost hidden beneath the eyes. Backswimmers, like other Hemiptera, have piercing, sucking mouthparts.
Adult backswimmers have functional wings and can fly, but they must first exit the water and right themselves. They use their first and second pairs of legs to grasp prey and cling to aquatic vegetation. Most mature backswimmers are less than 12 inches long.
Classification
Backswimmer Diet
Backswimmers eat other aquatic insects, including other backswimmers, as well as tadpoles and small fish. They hunt by diving down to catch submerged prey or drifting up under prey above them after releasing their hold on vegetation. Backswimmers feed by piercing and sucking fluids from their prey's immobilised bodies.
Almost all “true bugs” (members of the order Hemiptera) have piercing, tubelike mouthparts for sucking in their food. Backswimmers, like most other aquatic true bugs, prey on other aquatic insects as well as small fish and tadpoles — whatever they can catch.
They wait quietly for prey to pass by, then lunge quickly with a stinging bite that subdues the prey and starts the digestion process. The backswimmer then sucks in the liquified contents of the unfortunate insect.
Life Cycle of Backswimmer
Backswimmers, like all true bugs, go through incomplete or simple metamorphosis. In the spring and summer, mated females lay eggs in or on aquatic vegetation or on the surface of rocks. Depending on the species and environmental factors, hatching can take as little as a few days or as long as several months. Nymphs resemble adults, but they lack fully developed wings. The majority of species spend the winter as adults.
Backswimmers attach their elongated eggs to submerged plant stems. In general, the young resemble miniature versions of the adults, save for the absence of wings, which they acquire during their final moult.
Male backswimmers make scraping noises (stridulations) that appear to attract females; in this regard, they are similar to crickets.
Special Adaptations and Behaviors of Backswimmer
Backswimmers can and will bite people if they are handled carelessly, so use caution when collecting specimens from a pond or lake. They've also been known to bite unsuspecting swimmers, earning them the moniker "water wasps." Those who have been bitten by a backswimmer will tell you that it feels like a bee sting.
Backswimmers can stay underwater for hours at a time because they have a portable SCUBA tank with them. The backswimmer has two channels on the underside of the abdomen that are covered by inward-facing hairs. The backswimmer can store air bubbles in these spaces, from which it can draw oxygen while submerged.
When oxygen reserves are depleted, it must breach the water's surface to replenish the supply. Some species' males have stridulatory organs that they use to sing courtship overtures to receptive females.
Range and Distribution of Backswimmer Insect
When oxygen reserves are depleted, it must breach the water's surface to replenish the supply. Some species' males have stridulatory organs that they use to sing courtship overtures to receptive females.
Distribution of Backswimmer
Although the common backswimmer is commonly collected in Europe (Soós et al. 2009), it can be found from northern Africa to western Siberia and northwestern China (Berchi 2013). Notonecta glauca is most commonly found in inland freshwater ponds, but it can also be found in eutrophic (highly enriched in nutrients) freshwater bodies near the sea (Kjrstad et al. 2009). Many more Notonecta species can be found in North America north of Mexico (Torre Bueno 1905). It is unclear whether this species could become established in Florida if introduced, but its current range includes several locations with similar climates and habitats.
Air Retention
Despite the fact that N. glauca lives in water, it breathes atmospheric air and lacks gills. When these insects dive or rest beneath the water's surface, they produce a film of air that surrounds their bodies. This air film, also known as a superhydrophobic coating or surface, keeps the insect from getting wet. It also reduces the drag (Physics) caused by diving. N. glauca is covered in hairy structures, except on its head and legs, in order to create this air film around it. There are two types of hair, and having both types maximises air retention: setae and microtrichia. The density of the hairs is the most important factor in creating an air film.
Notonecta glauca has dense microtrichia and can maintain an air film for up to 120 days. The air film cannot last indefinitely because as an insect breathes, the oxygen partial pressure decreases and the nitrogen partial pressure increases, causing the air bubble to shrink in size.
Backswimmer Confused with Water Boatman
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People frequently mix up the backswimmer and the water boatman. It's because they physically resemble each other. Their modified long hind legs are used to row through the water. Notonecta is the genus name for the backswimmers. They appear to be larger than the average water boater. Backswimmers have triangular bodies and take the shape of a water boatman. The backswimmer has a keel-like structure on the top of his body that allows him to swim quickly around. These are mostly seen swimming backwards. The water boatman, on the other hand, has a more flattened shape from top to bottom. Backswimmer has short front legs that have not been modified.
The front legs of a water boatman are spoon-shaped, which aids in scooping organic and aquatic matter into the mouth. Backswimmers have a segmented rostrum that they use to bite their prey. A water boatman has a slightly corrugated appearance and transverse black lines on its body. The backswimmer, on the other hand, has bright red, yellow, or white patches on its body.
Backswimmers are found in open water, where they can easily pursue mosquitos and other aquatic insects. The water boatman is mostly found at the water's surface. They are difficult to find in shallow water. They are frequently seen in the water, hidden beneath a leaf or any other object.
Special Features of Backswimmers
The front legs of a water boatman are spoon-shaped, which aids in scooping organic and aquatic matter into the mouth. Backswimmers have a segmented rostrum that they use to bite their prey. A water boatman has a slightly corrugated appearance and transverse black lines on its body. The backswimmer, on the other hand, has bright red, yellow, or white patches on its body.
Backswimmers are found in open water, where they can easily pursue mosquitos and other aquatic insects. The water boatman is mostly found at the water's surface. They are difficult to find in shallow water. They are frequently seen in the water, hidden beneath a leaf or any other object.
Adult Backswimmers have the ability to fly. They hunt by remaining motionless on the water's surface. When they notice movement in the water, they swim towards it to see if it is worthwhile to catch. Backswimmer bites can be painful because their saliva is toxic.
Backswimmers should not be confused with the similarly shaped insect known as the Lesser Water Boatman (Corixa punctata). The Lesser Water Boatman feeds on algae while swimming on its front.
Other Fun Facts
In North America, there are approximately 125 species of water boatman.
They have the ability to shoot out of the water and begin flying at the same time.
They do not need to crawl out of the water before flying; they can fly directly from swimming.
It has the loudest voice when it speaks. When you sit in the first row and listen, it sounds more like a live orchestra.
FAQs on Backswimmer
1. What Do Backswimmers Do?
Answer: Backswimmers (Notonectidae family) are piercer-predators that kill and suck the bodily fluids of any invertebrate or vertebrate prey they can subdue, including tiny fish fry and tadpoles.
2. What Do Water Bugs Look Like?
Answer: One of the largest insects in the United States and Canada is the true giant water bug. Most species are about two inches long and one inch wide, but some can grow to be four inches long. Giant water bugs have flat oval-shaped bodies that are tan or brown.
3. What Causes Water Boatmen?
Answer: When the Water Boatmen appear, it is usually because there are algae in the pool. Maintain sufficient chlorine levels in your pool to break down algae and, if necessary, add a specialist algicide. Without algae, there is no food, and without food, there are no bugs! Shock your pool with chlorine at the first sign of algae.
4. What Happens if a Water Bug Bites You?
Answer: A bite will most likely cause no harm. As a result, these creatures are labelled as "harmless." Despite the fact that these enormous bugs are only considered a nuisance, some people have reported swelling, cramping, vomiting, fever, and difficulty breathing after being bitten.
