On this page a few more photos of this beetle. In the photo above he is sitting on a sprig of stonewort, a Chara species. The little orange balls are the Antheridia, the male 'flowers'. A silvery edge can be seen at the rear tip of the beetle: the edge of an air bubble that is stored under the elytra. All beetles from the Dytiscidae family carry their breathing air there. This also allows them to regulate their weight underwater: during a fast flight they can squeeze out the air to sink faster. They do this at the tip of the abdomen, which is shaped in such a way that there is a kind of watertight air valve. Once they gain weight this way, they may have difficulty pushing the abdomen tip against the surface of the water, especially if there are no plants. I have observed this a few times with the Great Diving Beetle.

Below is another photo of the swimming beetle. The suction cups (suction hairs in fact) on the front and middle tarses are clearly visible.

Click on the images below to see other photos of Agabus sturmii.

All pictures on this site were made by Gerard Visser (Aadorp, Netherlands), unless stated otherwise. All rights remain with him. These pictures may not be used for purposes any other than private viewing or printing. Do NOT hardlink to these pictures or place them on other websites without the author's approval. Should you need them for purposes which include third parties, you must ask the author permission by e-mail. People, who want to use this pictures for exhibitions or publications or educative material are much encouraged to do so, after approval as mentioned and giving the normal credits.