About Dytiscus latissimus Linnaeus, 1758
Dytiscus latissimus is one of the largest species of predaceous diving beetles in the family Dytiscidae; only the Brazilian species Megadytes ducalis grows larger than this beetle. D. latissimus can reach a body length of around 38–44 mm (1.5–1.7 in). This species is structurally similar to the better-known, more widespread Dytiscus marginalis, but D. latissimus is clearly larger and especially wider in shape. It is usually easy to recognize by the extensions present on both sides of its shield. Its elytra and pronotum are dark brown, with yellow edges along their sides. The head is black, and the legs are yellow. The wing cases of male D. latissimus are shiny, while the wing cases of females are finely grooved. D. latissimus is a voracious predator that hunts a wide variety of prey, including other insects, tadpoles, and small fish. Before diving, these beetles collect air bubbles in their wing cases, and this air passes through their spiracles. This species is found in northern and central European countries. It is listed on Annex II and Annex IV of the European Union Habitats Directive; Annex IV grants the species strict protection across all EU member countries. D. latissimus is an aquatic species. It lives in dense vegetation, dominated by Carex and Equisetum, at lake edges, in deep ponds, or in other nonflowing water bodies. A key habitat requirement for this species is a high abundance of case-making caddis flies, which are the primary food source for D. latissimus larvae.
