Some aquatic insects stridulate too, so it may not necessarily be a member of the Orthoptera (the group including grasshoppers, cicadas and crickets). However, I don't know to what extent any aquatic insects stridulate in the same ongoing way. As a youngster (back around 1950) I was fascinated by the Screech Beetle (Hygrobia tarda), which made funny noises when handled or otherwise under stress, but that was the only example I personally encountered.
Nice one. Sounds like one of the domino-ex modes, 8 or 16 I'm not sure. Now that they use output from PC soundcards they've come up with all kinds of crazy digital modes for different propagation circumstances.