Pond Skater at seven o'clock

The (one and only) water soldier stands guard on our pond, fighting a losing battle with the duckweed, and a lone pond skater. We haven't had this water soldier long, but they are supposed to float free in summer and produce white flowers on long stems above the water, and then in autumn they descend to the bottom, their roots find their way into the mud and debris there and they sort of hibernate. Then in spring, up they come again. I wait with baited breath!