Giant water scavenger beetles (genus Hydrophilus) are among the largest aquatic beetles, with some adults reaching up to 50 mm (2 inches) in length. They are completely aquatic in their adult stage, using specialized fringed hind legs to row through stagnant freshwater, and they are also strong flyers that migrate between ponds.
Habitat & Diet: They inhabit stagnant ponds and marshes. Adults are scavengers that primarily consume decaying organic matter and algae, while the larvae are voracious predators that hunt small invertebrates like snails and mosquito larvae.
Breathing Technique: Unlike other water insects, they hang suspended from the surface headfirst. They extend their antennae to break the surface film and trap a fresh bubble of air against their fuzzy underbelly, which looks like a silvery coating underwater.
Life Cycle & Eggs: Females lay up to 140 eggs in a waterproof, silken cocoon that typically features a protruding "mast" for ventilation. This cocoon is either attached to underwater vegetation, floated on the water surface, or carried by the female.
