Although the Water veneer moth (Acentria ephemerella) is visually drab and unexciting, it has a most fascinating life cycle. Found during the summer months around ponds and the slow-moving, more stagnant areas of rivers, it is widespread through the UK.
It is most unusual in that it is an aquatic species of moth, and whereas the male has a 12mm wingspan, most females have only vestigial wings, are flightless, and live under the water. The male mates with the female on the surface of the water, after which she dives below and lays her eggs amongst the water weeds. After hatching, an emerging larva bores into the stem of the weed, loosely spinning together parts of the plant to make a shelter. As the larva feeds, it damages the plant causing parts to break off and die. It is for this reason that it has been selected for use as a biological pest control agent against the watermilfoil plant (Myriophyllum spicatum).
Once fully grown, the larva pupates within an air-filled cocoon attached to a plant; it emerges as an adult moth and swims to the surface of the water. The males, together with the few females which have wings, then take flight.
