Giant water bug

Morphology

These bugs are large (15-23 mm) aquatic predators, characterised by their flattened bodies and strong raptorial forelegs. 

Evolution

Belostomatidae is a family of freshwater insects, found worldwide. 

Behaviour

These water bugs feed predominantly on other aquatic insects, including mosquito larvae. However, they have also been known to eat vertebrates, such as small fish and tadpoles! It is advisable not to catch these bugs with your bare hands as they can inflict a painful bite. Belostomatids are good swimmers and can chase after their prey over a short distance. They spend most of their time hanging in the water column waiting for an opportunity to catch prey. Males have been reported to make stridulatory sounds to attract females. Belostomatids have been seen communicating with each other by rhythmical push-up-like body movements near the surface of the water.

Method of reproduction

Sexual

Habitat

Aquatic

Lives in wetlands, ponds and lakes that have plenty of aquatic vegetation.

Distribution

Found throughout Australia.

Life Cycle

Female Diplonychus lay their eggs on the back of the male, who then protects them until hatching. The male will carefully stroke the eggs with his hind legs to maintain a fresh flow of water. However, if an egg gets dislodged he readily eats it! As in many other groups of aquatic bugs, belostomatid nymphs stay away from adults to avoid being eaten. Nymphs pass through five growth stages (instars) prior to becoming an adult. The nymphs appear similar to the adults except smaller and lacking fully-developed wings.