Скачать или смотреть Larva of an aquatic Diving Beetle (Dytiscidae sp) - Brighton, April 2025

Dytiscidae sp. refers to any of the many species of "diving beetles" belonging to the family Dytiscidae in the suborder Adephaga in the order Coleoptera. They are sometimes called Water Tigers.

The suborder Adephaga contains over 40,000 species in 10 families, 6 of them represented in the UK of which Dytiscidae is one.

Almost all are aquatic, predatory insects with streamlined bodies adapted for swimming, found in a variety of freshwater environments including puddles, ponds, ditches, canals and other slow-moving waterways.

Adults are shiny black/brown/olive beetles, sometimes with yellowish marks. Their bodies are streamlined, oval, with the narrower end at the head. The antennae are threadlike. These beetles hang head downward, with the tip of the abdomen protruding from the water surface. The hind legs are fringed with hairs and flattened for swimming. When they do so they kick both hind legs simultaneously.

They have membranous hind-wings covered by fore-wings, which form thick, heavy shields called elytra.

Larvae, like the one seen in this video have elongated, flattened bodies up to 5cms long with three pairs of legs. Although equipped with gills and siphons, they occasionally need to come to the surface in order to draw air into 'spiracles' (snorkel-like protuberances) located at the hind end of the body.

Ferocious predators, some lie still, ready to pounce on almost any living thing that strays too close, including other Dytiscidae larvae.

Others actively stalk prey. Either way they use their powerful jaws to grasp their prey and inject digestive enzymes that liquefy the soft tissue of their victims, allowing the larvae to suck them dry.

After several moults, the fully-grown larvae leave the water, dig themselves into nearby mud and emerge a few weeks later as a fully formed beetle. Once their skin has hardened, they make their way back into the water, mate and commence the cycle once again.

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PK