---

I've seen really large mud wasps - the size of hornets - land on the surface of billabongs in the outback of Australia, clearly to sip water. I don't know if they were then making mud by combining it with soil, or whether they needed the water for their own rehydration. This wasp appears to be standing on the water surface, rather than having drowned, so maybe it is engaged in a similar way.

Mind you, I know from having a pool in Australia, one is always fishing drowned inverts out. This can sometimes be a nasty surprise, when the spider you have just fished out not to be drowned, just a bit waterlogged - it's one of those things Australian children get taught not to do, as the beast can revive and bite you.