The sunburst diving beetle or spotted diving beetle (Thermonectus marmoratus) is one of our eye-catching invertebrate species found in Investigate, part of Paignton Zoo’s Lower Vertebrate and Invertebrate (LVI) department. The Zoo received 80 beetles from ZSL London Zoo in November, so they are a relatively new addition to the collection. The beetles are a firm favourite of LVI Curator Luke Harding - he even has an off-show collection in his office!

The family Dytiscidae consists of many diving beetle species, including the sunburst diving beetle. This family has unusual adaptations that allow them to dive and maintain their aquatic lifestyle. When you’re in Investigate, look very closely at a beetle that’s diving... you will see an air bubble at the tip of the beetle’s abdomen which allows it to breathe underwater! They have to surface regularly to renew the air bubble so they can continue their quest for food. Also, their hind legs are fringed, which allows them to build resistance against the water and dive deep to find food items. The male sunburst diving beetles also have suction disks on each foreleg in order to aid mating. 

But that’s not even the most amazing thing about these beetles! This species has remarkable eyes. They have two retinas and bifocal vision, which allows them to switch their vision from near and distance; much like humans! This is currently a key topic in Dysticidae research as sunburst diving beetle larvae are said to have the most unusual eyes in the animal kingdom.

In the wild sunburst diving beetles can be found near water sources in southern California, New Mexico, Arizona and Mexico. They feed on other invertebrates including mosquito larvae. At Paignton Zoo the sunburst diving beetles are fed on glass worms and optimum water quality is ensured by providing regular water changes. 

With their bright yellow spots, mimicking bursts of sunshine, these attractive beetles can be found in the cylinder enclosure near the back wall of Investigate. An absolute must-see for bug lovers and budding naturalists – and, quite frankly, for everyone else, as well!

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