Water boatmen, belonging to the family Corixidae, are common aquatic insects frequently seen in ponds, lakes, and slow-moving streams. These small, oval-shaped bugs typically measure less than half an inch in length and possess a flattened back often marked with narrow, dark, parallel crosslines. They are often observed navigating underwater, appearing at home in their watery environment. The question of whether these seemingly water-bound insects can actually fly is a common point of curiosity.
Yes, They Can Fly
Water boatmen are indeed capable of flight, despite their primarily aquatic lifestyle. Adult water boatmen possess well-developed wings, which they acquire during their final molt. This ability to fly allows them to leave their aquatic habitat and venture into the air. Flight is often observed when they emerge from the water, particularly at certain times of the year. They are strong fliers and are known to be attracted to artificial lights at night, sometimes ending up in swimming pools or birdbaths after a nocturnal flight.
Why Flight is Essential for Survival
Flight serves several purposes for the survival and dispersal of water boatmen. One primary reason is escaping temporary or deteriorating habitats. When ponds or other shallow water bodies begin to dry up, flight allows water boatmen to seek out new, more suitable aquatic environments.
Flight also facilitates dispersal to new areas, which is important for finding new food sources and locating mates. Additionally, flight provides a means to avoid aquatic predators. If a water body becomes too dangerous due to a high concentration of predators, water boatmen can simply fly away to a safer location.
The Mechanics of Water Boatman Flight
Water boatmen are anatomically equipped for both aquatic and aerial locomotion. They have two pairs of wings: forewings, known as hemelytra, which are somewhat hardened and serve as a protective cover, and membranous hindwings used for actual flight. When at rest, the hindwings are folded neatly beneath the forewings. The forewings are attached to the mesothorax and typically lie flat over their body.
To transition from water to air, water boatmen must emerge from the water. They carry a thin, silvery bubble of air, called a plastron, trapped against their body and under their wings. When ready to fly, they surface, and their wings, previously held tightly against their body, become functional for flight. During flight, the forewings are held outstretched, similar to a lady beetle, while the hindwings rapidly beat to provide propulsion.
Distinguishing Water Boatmen from Backswimmers
Water boatmen (family Corixidae) are often confused with backswimmers (family Notonectidae) due to their similar aquatic habitats and ability to fly. However, several differences exist between these two insect groups. Water boatmen typically swim right-side up, often near the bottom of ponds, using their long, oar-like hind legs for propulsion. Their bodies are flatter and exhibit fine, transverse black lines on their backs. They possess short, scoop-shaped front legs used for gathering food, primarily algae and detritus.
In contrast, backswimmers are named for their habit of swimming upside down, with their belly facing upwards. Their bodies are more boat-shaped with a keeled back, and they tend to frequent open water. Backswimmers are predatory insects with a piercing beak and can deliver a painful bite if mishandled. Visually, backswimmers have a light-colored back and a darker underside, which serves as camouflage when swimming inverted.