Water Scorpions in Florida

Water scorpions --- insects of the family Nepidae --- take their common name from their superficial resemblance to true scorpions. These harmless insects spend their lives in or near water, where they hang head down, waiting to ambush prey. Although several genuses of water scorpions are found in wetter areas of North America, only those of the genus Ranatra, characterized by a long twiglike body, are found in Florida.

  1. Kinds of Water Scorpions

    • Water scorpions of all types have pincher-like front legs and a long whiplike tail, which lends them a superficial resemblance to actual scorpions, but these insects are unrelated. Water scorpions belong to the insect order Hemiptera, and their long "tail" is a breathing tube that extends above the water line as the insects hang head down waiting for prey. In most areas of Eastern North America, water scorpions of the genus Nepa --- a broad, flattened insect that resembles a dead leaf --- and the various genuses of Ranata are found, but only the Ranata occurs as far south as Florida.

    Life Cycle

    • Water scorpions lay eggs on the stems of aquatic plants. These eggs have two small horns that allow the submerged young to breathe. Adults position themselves head down in water with their breathing tubes above the surface and ambush passing prey, which includes mayfly nymphs, crustaceans and small worms. With their long beak, they pierce the prey and suck out its juices. The average lifespan of water scorpions is undetermined.

    Underwater Breathing

    • Although water scorpions spend most of their lives underwater, they rely on their breathing tubes for oxygen. Adult water scorpions maintain a bubble of air on the abdomen, which is regularly replenished through the breathing tube for longer stays underwater. Since water scorpions occur in colder climates where ice forms on water surfaces, this air bubble allows them to survive submerged through the winter.

    Water Scorpion Habitats

    • Averaging over 1 inch in length as adults, water scorpions possess two sets of wings and can fly for short distances to populate new areas. They may hide in vegetation at water's edge during the day and return to the water at night to wait for prey. Although Ranatra can be found in marshy areas throughout Florida's interior and coastal regions, it poses no threat to humans and can even be kept in aquariums.