The Sunburst Diving Beetle (Thermonectus marmoratus) is a small, soft-bodied, aquatic, freshwater insect. It is also known as the Spotted Diving Beetle.

The Sunburst Diving Beetle is black with bright yellow spots. The bright spots act as a defence mechanism to warn away predators. It has a black shell, called a carapace. It has wings that are protected by the carapace. The male has a suction cap on each foreleg (front leg).

Sunburst Diving Beetle

It measures 1.5 centimetres (half an inch).

The Sunburst Diving Beetle is found in the creeks of Mexico and North America, in states such as southern California, southern Utah, Arizona, New Mexico, and Texas. It lives in water, and is a good swimmer. It prefers slow-moving, shallow pools and creeks. When the creeks become dry, it flies to a new creek.

It mainly eats mosquito larvae, but it will also eat insects, snails, and tadpoles.

The female lays eggs just above the water. A few days later, the eggs hatch into ‘water tigers’ – the larvae stage. The larvae crawl back into the water and begin eating small insects. When they are mature, they climb out of the water and burrow into soft soil. In the soil, they pupate and metamorphose into adult beetles.

Sunburst Diving Beetle

Sunburst Diving Beetle

Sunburst Diving Beetle

Sunburst Diving Beetle

Photographer: Martina Nicolls

Martina Nicolls: SIMILAR BUT DIFFERENT IN THE ANIMAL KINGDOM