I’ve kept this whirligig beetle
(Gyrinus natator) a few days in a glass-bowl filled with pond water in order to study its behavior.
Gyrinidae are the only beetles that colonize the water surface and so they have a number of interesting and unique characteristics. They are extremely good swimmers and divers. Their hind legs are highly adapted for swimming and they carry a bubble of air trapped beneath their elytra. The eyes are divided into two parts, one for viewing things above water, the other forseeing underwater. Whirligigs are handsomely coloured with a sombre lustre of steely grey or bronze.
I tossed a living ant on the water surface. The whirligig beetle circled around a few times, then sped directly toward and touched her for a split of a second. Immediately the ant didn’t move any more. I have no idea how he could kill or paralyze so quickly.
Around 11x magnification. 265 exposures taken with EOS 5D, Mitutoyo M Plan Apo 10x, ISO 100, flash, paper cylinder diffuser, stacked with Zerene (mix of DMap & PMax method).
A great post about the same species by
John Hallmen (including stereograms).
