I was really surprised to see these here so soon after we built the pond, but it just goes to show: "Build it and they will come"
in Russian, we use to say smth like that: 'a nice spot will never stay empty'
last summer I was fascinated to witness such a case: I was standing on the road, near the entrance to the store, there was a big nice puddle in the asphalt. then I suddenly noticed something rather big and solid buzzed from the air and flopped into this puddle. I got on my knees to understand what it was - and it turned out that it was a swimming beetle !!! before this incident, I didn’t know that they can fly and move between puddles, I was sure that they only swim, hehe. so -- there is always a scope for self-education...
!BEER