|White Beach Tiger Beetle - Cicindela dorsalis media|
Family Carabidae - Ground Beetles) / Subfamily: Cicindelinae (tiger beetles)
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Live adult tiger beetles photographed at Florida, USA.
Cicindela dorsalis media
Cicindela dorsalis was named by Thomas Say in 1817, and Cicindela media by John LeConte in 1857; currently, these two are considered subspecies of the same species. C. dorsalis media occurs long the southeast coast of the United States, including South Carolina and C. dorsalis dorsalis occurs along the northeast coast. Two other subspecies, C. dorsalis saulcyi and C. dorsalis venusta, are found along the coasts of Florida, the Gulf of Mexico and Mexico.
The white beach tiger beetle ranges from 10.5 to 13.5 mm (0.41 to 0.53 inches) in length. Like all tiger beetles, its legs and antennae are long and slender and its jaws are large. The elytra (wing coverings) are white with bronze markings; the head and pronotum are white. The pronotum and sides of the under surface are densely covered with white hairs. The sides of the elytra of males are nearly parallel whereas females are somewhat more broadly rounded. The pale coloration renders the beetle well camouflaged on the light sand where it lives.
The northern white beach tiger beetle, C. dorsalis dorsalis, is on the federally threatened list because of extensive destruction of its habitat. This subspecies historically ranged from Massachusetts to the Chesapeake Bay and is now found only in the Chesapeake Bay area. Even there, the narrow beaches, 3 to 10 meters (9.8 to 32.8 feet) in width, are barely wide enough to support this beetle. The related subspecies in South Carolina, the southern white beach tiger beetle (C. dorsalis media), is being extirpated in parts of its range as well; however, there is no federal or state ranking for this species.
POPULATION DISTRIBUTION AND SIZE: This beetle historically ranged from southern New Jersey to Miami, but its range has been diminished at both extremes. In South Carolina, it once occurred on all wide sandy beaches, but no longer is present where human development or severe erosion have destroyed appropriate habitat, such as in the city of Myrtle Beach (Knisley and Schultz 1997). It still may be found on Cicindela dorsalis media those beaches that are relatively undisturbed, including Waites Island, Cherry Grove Beach, Huntington Beach, Isle of Palms, Folly Island, Seabrook Island and Edisto Beach; the largest population is at Seabrook Island where the dunes are most extensive. It occurred on Hunting Island as recently as 2002 but the beach has undergone severe erosion so its current status is in doubt. Population size for the white beach tiger beetle has not been determined in South Carolina.
HABITAT AND NATURAL COMMUNITY REQUIREMENTS: The adult white beach tiger beetle is a predator; the adults run actively on the sand to catch prey that includes small insects. Larvae are also predators, hiding in burrows with only their jaws protruding to catch unwary insects or a variety of small animals of suitable size that come within their reach. Therefore, larvae need a safe place for development above the high tide line; both stages require a large enough expanse of naturally shifting ocean beach so that sufficient prey is available.
CHALLENGES: Loss of habitat represents the most significant challenge to South Carolina’s white beach tiger beetle. Building and road construction, deposition of dredge spoil, extensive driving on the beach and heavy foot traffic can destroy the natural qualities of a beach so as to make it uninhabitable by beach tiger beetles. Erosion can narrow or eliminate the sandy beach and severely impact the beetles. Construction of groins and bulkheads reduces natural movement of the sand and suitability for these tiger beetles (Knisley and Schultz 1997). Water quality offshore needs to be moderately clean and free from toxic substances (such as oil spills) so that aquatic and semi-aquatic animals are available as prey for tiger beetles and so that larvae are not poisoned in their burrows (Knisley and Schultz 1997).
CONSERVATION ACCOMPLISHMENTS: Efforts to save the endangered least terns on our public beaches also contribute to an environment suitable for tiger beetles. This effort is largely fencing off tern nesting areas and informing the public about the necessity to protect the terns. Actions to protect the dunes themselves, such as keeping people off the dunes, preventing sea oats collection and prohibiting structures such as groins and bulkheads all contribute to a good habitat for these beetles.
This tiger beetle ranges from 10.5 to 13.5 mm (0.41 to 0.53 inches) in length. Like all tiger beetles, its legs and antennae are long and slender and its jaws are large. The pronotum and sides of the under surface are densely covered with white hairs. The sides of the elytra of males are nearly parallel whereas females are somewhat more broadly rounded. The pale coloration renders the beetle well camouflaged on the light sand where it lives.
1. Janet C. Ciegler and Joey Holmes, White Beach Tiger Beetle South Carolina Department of Natural Resources
2. Boyd, H.P. 1982. Checklist of Cicindelidae: The tiger beetles. Plexus Publishing, Inc. New Jersey. 31 pp.
3. Knisley, C.B. and T.D. Schultz. 1997. Tiger beetles and a guide to the species of the South Atlantic states. Virginia Museum of Natural History, Martinsville. 209 pp.
Order Coleoptera: Beetles are the dominant form of life on earth: one of every five living species is a beetle. Coleoptera is the largest order in the animal kingdom, containing a third of all insect species. There are about 400,000 known species worldwide, ~30,000 of which live in North America. Beetles live in nearly every habitat, and for every kind of food, there's probably a beetle species that eats it.
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