Common backswimmer

The common backswimmer (Notonecta glauca) is a member of the order Hemiptera and the family Notonectidae. This predatory aquatic insect is widely distributed and is characterized by its unique habit of swimming upside down, using its long, oar-like hind legs to propel itself through the water column with high precision.

Within the context of aquaculture and fisheries, this insect is considered a significant pest. Backswimmers are opportunistic hunters that target small aquatic organisms, including fish fry, larvae, and tadpoles. Their ability to deliver a painful bite, often referred to as a "water bee sting" in humans, reflects their potent predatory nature.

The life cycle involves incomplete metamorphosis (hemimetabolous). Eggs are deposited on submerged aquatic vegetation. Nymphs emerge and undergo several developmental stages, resembling miniature adults. They are highly mobile and capable of flight, allowing them to colonize new ponds and water tanks quickly during the warm season.

The economic impact of Notonecta glauca is primarily observed in hatchery ponds and nurseries. By preying on fish fry, they can decimate populations of fingerlings, leading to significant yield losses. Additionally, physical injuries caused by their piercing mouthparts can induce secondary infections in surviving fish, further decreasing the overall health of the stock.

Effective management strategies for minimizing backswimmer populations involve consistent maintenance of water bodies. This includes physical removal of excessive aquatic weeds to limit egg-laying sites and the installation of fine-mesh screens on water supply intakes to prevent adult ingress. Biological control and maintaining optimal fish density are also recommended to reduce the impact of these aquatic predators.