1/4 Vernacular Name BEETLE, SUNBURST DIVING (aka: spotted diving beetle) Adult Larva GEOGRAPHIC RANGE Extreme southern California, Arizona, New Mexico, Texas and Mexico. HABITAT Ponds and lakes, requiring at least a temporary water source. CONSERVATION STATUS • IUCN: Not Evaluated (2012). COOL FACTS • They wear bifocals! The sunburst diving beetle, in its aquatic larval stage, has been found to have, in its principal eyes, 2 retinas and 2 distinct focal planes that are substantially separated, acting like bifocals to switch their vision from up-close to distance. This gives them the easy and efficient ability to capture their prey. This is the first ever recorded use of bifocal technology in the animal world. • Their bright color advertises their bad taste. • They are streamlined, have powerful oar-like hind legs for propulsion and steer with their short forelegs. • Like many aquatic insects, they carry surface air beneath their wings to breathe under water. • These beetles are useful because they eat other invertebrates including mosquito larvae and pupae. DIET • In the wild: mosquito larvae, pupae, small insects and anything unlucky enough to get too close. • In captivity: mealworms and crickets. Sunburst Diving Beetle 2/4 LONGEVITY • In the wild: 2 years. • In captivity: 2 years. ENEMIES - DEFENSE • Enemies: birds, fish. Larvae may be cannibalized by adults. • Defense: - their bright color advertises their bad taste. - they escape some predators by diving deep. MATING - CARE OF THE YOUNG • When it is time to reproduce, female diving beetles enter the water and usually lay their eggs in sand or on the stems of aquatic plants and macro-algae. • Sunburst diving beetles undergo complete metamorphosis. • The eggs hatch into what are known as water tigers and feed on small invertebrates. The larvae pupate and eventually the adult emerges. • Sexual Maturity: they are ready to breed a few weeks after emerging from the pupae. SOCIAL INTERACTION • They are gregarious and cannibalistic. LIFE STYLE • Activity Period: cathemeral. • Active all year: central to their activity is the presence of a water source. When the summer monsoon season arrives, many temporary ponds are inhabited by these diving beetles. • Feeding: - when hunting, these beetle larvae either swim around actively or hang, with their tail touching the surface, just below the water line. When they spot a prey animal, they swim over and strike the target with their powerful mandibles. Unlike the adults, larval diving beetles gradually suck the fluids from their prey. - sunburst diving beetles have been observed swarming a prey item and feeding en masse. - the adults prey on a variety of aquatic animals by tearing them to shreds with their powerful mandibles. • Locomotion: they are strong, proficient swimmers using their powerful hind limbs to propel them through the water and they can fly from one water supply to another. • When their water source dries up, they will fly to a new one. PHYSICAL • General Description: they are small black bugs with yellow spots. • Sexual Dimorphism: females are slightly larger and only males have a suction disk on each foreleg. • Size: 1/2". • Color: the carapace is black and streamlined, covered with bright yellow or golden spots. • Their streamline body aids in swimming effortlessly through the water. Sunburst Diving Beetle 3/4 • Eyes: - larvae have stemmata, which are commonly seen in larval insects. Stemmata are simple lens eyes that rely on superficially similar optical principles to vertebrate eyes. On each side of the head, the larvae have 6 stemmata as well as a lens-less eye patch. Within each of these eyes there are 2 distinct retinas, one on top of another. In total, this means that these larvae have 14 eyes and 28 distinct retinas. - adults have typical arthropod compound eyes that are made up of repeating units, the ommatidia, each of which functions as a separate visual receptor. TAXONOMY Phylum Arthropoda Class Insecta Order Coleoptera Family Dytiscidae Genus / species Thermonectus marmoratus REFERENCES - http://dallaszooed.com/animalfacts/animalfacts.php?id=73&ci=14&li=15&name=PQRS - http://cincinnatizoo.org/blog/animals/sunburst-diving-beetle/ - http://arthropoda.wordpress.com/tag/diving-beetle/ - http://eol.org/pages/1171174/overview - http://en.wikipedia.org/wiki/Thermonectus_marmoratus - http://bugguide.net/node/view/73536/bgimage Prepared by: Dave Schaffer, docent Date: 11-24-12 Photos by: Map by: Dave Schaffer & Bob Sloane, docents Larva: http://bugguide.net/node/view/73536/bgimage Adult: John Bernard, docent Approved by: Marina Haynes, Curator, Children’s Zoo Date: 12-02-12 Formatted by: Dave Schaffer, docent Date: 11-24-12 Sunburst Diving Beetle 4/4 This page left intentionally blank. .