I'm pretty sure none of those things can swim...
Well... since the cows and the kindergarten teachers can fly, surely the insects are more than able to swim.
Except for some lucky spiders. But the better word is "float", I guess.
"Waiter, what is this fly doing in my soup?"
"The backstroke sir."
And including "float" in the hover hint would be lovely. Reported.
'flies, spiders, bees and butterflies are floating on my water'
Surely if they are floating, they are floating 'on' the water, and if they are swimming they are 'in' the water.
There's a big difference between floating and swimming. Also, yuck.