Description: A large aquatic hemipteran among the so-called giant water bugs, recognized for its broad, flattened, dark-brown body that blends effectively with murky substrates. Its forelegs are modified into raptorial hooks used to seize prey, while the hind legs act as efficient paddles. Adults possess a pair of respiratory spiracles at the tip of the abdomen, functioning like a snorkel for surface air intake. Mild sexual dimorphism is present, with females generally being slightly more robust.

Geographical distribution: Found across subtropical and temperate regions of South America, with confirmed records in Argentina, Uruguay, Paraguay, southern Brazil, and nearby areas. It is common in wet lowlands and water systems connected to major basins, where the species maintains stable populations.

Habitat: Occupies shallow ponds, marshy pools, slow-flowing river margins, floodplain channels and temporary wetlands, preferring calm waters with abundant submerged vegetation. It may also survive in seasonal water bodies as long as sufficient microfauna is available.

Diet: A vigorous predator, feeding mainly on small fish, tadpoles, amphibian larvae, aquatic insects and other invertebrates. It uses its specialized mouthparts to inject digestive enzymes that liquefy prey tissues, which are then ingested by suction. This feeding strategy makes it an important regulator of macroinvertebrate populations.

Behavior: Moves slowly through vegetation, often remaining motionless to ambush prey. It shows mostly nocturnal activity, though it can be seen during the day in clear waters. When threatened, it adopts a defensive posture, raising its body and displaying the powerful forelegs. Short flights between water bodies occur, especially after heavy rains or habitat drying.

Reproduction: Unlike many other aquatic hemipterans, males commonly provide care by carrying eggs on their backs, where females deposit them. This behavior ensures proper aeration and greater protection from predators. Juveniles, or nymphs, pass through several instars before reaching adulthood.

Conservation status: Currently considered a species without major global threats, owing to its wide distribution and tolerance of moderately altered habitats. Even so, wetland loss, agrochemical contamination and severe water pollution can negatively impact local populations.

Author of this compilation: EcoRegistros – 12/12/2025