Water boatmen are common aquatic insects found in freshwater environments, often observed in ponds, lakes, and slow-moving streams. These insects sometimes raise concerns about their potential to harm humans. Understanding the distinctions between different types of water boatmen is key to clarifying whether they pose any danger to people.
Identifying Water Boatmen
There are two primary groups often referred to as “water boatmen,” each with distinct characteristics and behaviors. True water boatmen belong to the family Corixidae. They have flattened, oval-shaped bodies, ranging from 2.5 to 15 mm in length. These insects possess short front legs and long, oar-like hind legs, which they use for propulsion while swimming right-side up. True water boatmen feed on algae, detritus, and other plant matter.
Another group often confused with true water boatmen are backswimmers, belonging to the family Notonectidae. Backswimmers have more rounded bodies and longer front legs compared to true water boatmen. A distinguishing feature of backswimmers is their habit of swimming on their backs, using their long, hair-fringed hind legs to propel themselves through the water. Unlike true water boatmen, backswimmers are predatory, feeding on other aquatic insects, tadpoles, and small fish.
Are They Dangerous?
The question of danger from water boatmen primarily relates to backswimmers (Notonectidae), as true water boatmen (Corixidae) do not bite humans. Backswimmers can inflict a painful bite if they feel threatened or are handled. They use their piercing mouthparts to inject digestive enzymes.
The sensation of a backswimmer bite is compared to a bee sting or a sharp prick, causing a burning sensation. While the bite can be painful, it is harmless to humans. The enzymes injected are not poisonous to humans and cause only temporary localized pain, redness, or swelling at the bite site. Severe allergic reactions are rare, but individuals sensitive to the injected substances might experience a more pronounced response.
Encountering Water Boatmen
When in natural bodies of water like ponds or lakes, exercising caution can help avoid encounters with backswimmers. Disturbing the water surface before entering can encourage these insects to move away. Backswimmers are attracted to light, so avoiding bright lights near water at night can also reduce their presence.
If a backswimmer bite occurs, simple first aid measures are sufficient. Clean the affected area with soap and water to prevent infection. Applying a cold compress or ice pack to the site for about 10 minutes can help reduce pain and swelling. Over-the-counter pain relievers or antihistamines may provide additional relief if needed.
Seek medical attention if symptoms worsen, signs of infection like increased redness or pus appear, or if a severe allergic reaction, though rare, is suspected.