It is found in Algeria, Austria, Belgium, France, Germany, Italy, Liechtenstein, Luxembourg, Morocco, the Netherlands, Portugal, Romania, Slovakia, Slovenia, Spain, Switzerland, Tunisia, and the United Kingdom.

The specific part of the scientific name, mercuriale, is because of the distinctive markings on the second segment of the abdomen that resembles the astrological symbol for the planet Mercury - ☿.

[3] They require areas of open vegetation, mixed with slow flowing water in which to lay their eggs.

It is thought that 25% of the world population exists within the United Kingdom but it has declined by 30% since 1960 due to changes in grazing, land drainage and water abstraction.

This nature reserve is owned and managed by the Devon Wildlife Trust and grazing has been re-introduced there to help encourage this species which had not been recorded there since 1988.