Whirligig beetle  (Gyrinus substriatus)

Biology

This whirligig beetle is active during the day, and is often found in large numbers, whirling around on the surface of the water; when disturbed they are able to dive to safety. They carry an air bubble around with them on the tip of the abdomen, which is periodically replenished, and enables them to stay submerged for long periods.

During autumn, the adults fly at night in search of new ponds. In July and August the larvae undergo pupation on land, protected by a cocoon of plant matter and sand grains; the adults emerge 10 days later. Both the larvae and adults are predatory, taking prey such as mosquito larvae and other aquatic invertebrates (4).

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