Heterocerus flexuosus Stephens, 1828

This species is generally associated with coastal saline or brackish water habitats but there are inland records scattered across Europe, mostly from salt pits or workings but sometimes where the substrate is naturally salty. The species occurs around the coasts of Europe; it is generally very local and rare in the south but more common in the north where it extends to the UK and, sporadically, to the Arctic Circle in Fennoscandia. Further east it is recorded from Turkey, Israel (since 1999) and Jordan and along shores of lakes and rivers in Kazakhstan, Tajikistan, Uzbekistan, Turkmenistan, Pakistan and Mongolia, and it has recently been recorded from Iraq, Syria and Saudi Arabia (Skalicky, 2014) In the UK it is almost exclusively coastal although there are a few records from the English Midlands near Leicester; there are scattered records from the coasts of England and Wales, including Anglesey, except for much of the north east and the West Country, and from Northern Ireland (near Belfast). The usual habitats are margins of brackish pools, estuaries and salt marshes with patchy vegetation on silty or sandy substrates, Adults have been recorded throughout the year except for November and December, they peak in abundance during June and it is likely that winter is passed in this stage. They live in colonies and spend most of their time burrowing among wet substrate, where they feed on algae and organic debris, but they become active and sometimes swarm on warm days when they may be seen in numbers on the surface. The biology is not known but is very likely to be typical of the family with breeding occurring in the spring and larvae developing among substrate. Sampling is easiest by searching among suitable substrate, they are easily flushed out by local flooding and the species has often been attracted to light, including UV black lights.