Two-spotted Diving Beetle
Agabus bipustulatus
The two-spotted diving beetle is one of the most common and adaptable water beetles in Europe. It inhabits almost every type of freshwater habitat, ranging from temporary puddles to lakes and slow-moving streams. It is a proficient predator that lives in the water as both a larva and an adult, though it is also capable of flying to colonize new environments.
Details
Identification
Oval, black body; two characteristic red spots on the vertex of the head (often only visible upon close inspection); fine, reticulate sculpture on the elytra.
Social behavior
Solitary; interactions are largely limited to the mating season, although they can occur in high densities in the same location.
Diet
Both larvae and adults are predatory, feeding on insect larvae (e.g., mosquito larvae), small crustaceans, and worms.
Hunting strategy
Active searching and pursuit of prey underwater; capturing prey with their mandibles.
Spawning substrate
Eggs are typically deposited into the tissue of aquatic plants or into underwater crevices.
Overwintering
Usually overwinters as an adult in the water or in moist substrate at the water's edge.
Ecology
Ecological role
Important predator in aquatic food chains, contributing to the regulation of insect populations.
Natural predators
Fish, larger water beetles (e.g., Great Diving Beetle), predatory water bugs, amphibians, and waterfowl.
Competitor species
Other diving beetles of the genera Agabus and Ilybius.
Ecosystem service
Biological control of mosquito larvae in small water bodies.
Threats
Destruction of small water bodies, intensive agriculture (pesticides), and general water pollution.
Scientific profile
Profile
Distinguishing features
Body length 9-11.5 mm; prosternal process narrow and pointed; elytral micro-reticulation consists of distinctly elongated meshes; male hind tarsi with suction hairs.