The lesser water boatman is a native aquatic insect common in most freshwater habitats. There are many different but very similar species of "lesser" waterboatmen in the UK and it can be very hard to identify them. Some are only about 0.5 cm some up to 2cm, but unlike the unrelated greater water boatman or backswimmer, the lesser waterboatman is a detritus feeder and eats dead plant material and other organic matter.
Lesser water boatman (Corixa sp)
Lesser water boatmen breed in the spring and deposit eggs on the leaves and stems of aquatic plants aswell as rocks and wood. The young are very small and go through several moults before becoming adult water boatmen.