Body length 14 - 16mm. Swim on their backs with a pair of legs adapted for use as oars. There are four species that superficially look very similar but inspection of their hemielytrons will sort them to species. N. glauca has hemilytrons pale pinkish grey and is by far the commoner species in lowland waters.
Ponds, ditches and other small water bodies. Avoids acid or peaty waters. Adults can fly to new water bodies. They feed on other water insects and small fish and tadpoles.
Status and distribution
Common and well distributed through most of England except the West Country, less common in Wales and highland Scotland, avoiding acid water.
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