PLECOPTERA: STONEFLIES
Definition
- Adults with 4 wings for flight. At rest the wings are folded flat over the abdomen, or partly rolled round. The antennae are long and thread-like. The end of the body has two thread-like ‘tails’.
- The adults have weak chewing mouthparts but the larvae have stronger jaws for eating small invertebrates.
- Larvae aquatic in flowing water only. They lack obvious external gills (present in mayflies).
- Life cycle egg, larva looking like a wingless adult, and adult.
What they do & where they live
- Larvae are predatory in streams and rivers. Adults sit on nearby vegetation.
- They are widespread. The greatest number of species tends to be in upland districts where the range of ecological conditions is generally greatest.
Number of species
- In Britain 33 species.
- The world fauna is variously cited as 1,600 to 3,000 species.
It's amazing Most stoneflies are small or only modest sized. But in northern rivers there are monsters over 25 mm long.
