Tooth Cave Ground Beetle

Rhadine persephone

Description

A moderately robust and convex beetle, the reddish brown Tooth Cave ground beetle, Rhadine persephone, attains a maximum length of only 0.35 in (8 mm). This cave-adapted species has only rudimentary eyes.

Behavior

The Tooth Cave ground beetle is suspected to feed on cave cricket eggs. The beetle's reproductive biology is unknown.

Habitat

The Tooth Cave ground beetle is endemic to two caves in the Edwards Limestone formation. Tooth Cave is up to 100 ft (30 m) in length and contains a greater diversity of fauna than any other cave in Texas. Over 48 species have been identified, and other highly adaptive cave fauna no doubt remain to be discovered.

The other known habitat of this beetle is Kretschmarr Cave, which is about 50 ft (15 m) deep. Fauna present in Kretschmarr Cave include the blind millipede Cambala speobia and several species of beetles. An associated insect, the Kretschmarr Cave mold beetle (Texamaurops reddelli ), is also federally listed as Endangered.

Distribution

This species is a highly localized example of the fauna endemic to caves in the Edwards Limestone formation in Travis County, Texas.

The Tooth Cave ground beetle, first discovered in 1965, is only known from Tooth and Kretschmarr caves. Exact population figures are not known. Few individuals of this species have ever been collected, and although its habitat area is large in comparison to its body size, the total population is probably small.

Threats

The only two caves inhabited by the Tooth Cave ground beetle are close to a road leading to residential and industrial areas, and are vulnerable to further development as well as spills of hydrocarbons and other potentially degrading chemicals. Without safeguards, these caves could collapse, become filled, or have their groundwater hydrology changed through a modification of either surface or underground drainage. The shallow caves are also easily accessible, which means they could be invaded by non-native invertebrate predators or competitors, such as alien sowbugs, cockroaches, or fire ants.

Conservation and Recovery

Because the region surrounding Austin also supports the black-capped vireo (Vireo atricapillus ), the Tooth Cave ground beetle and other karst insects are included in the 1991 U. S. Fish and Wildlife Service Recovery Plan for the vireo.

Contact

U. S. Fish and Wildlife Service
Regional Office, Division of Endangered Species
P.O. Box 1306
Albuquerque, New Mexico 87103-1306
Telephone: (505) 248-6911
Fax: (505) 248-6915
http://southwest.fws.gov/

References

Barr, T. C., Jr. 1974. "Revision of Rhadine LeConte (Coleoptera, Carabidae); Vol I. The Subterranean Group." American Museum Novitates 2359.

Reddell, R. R. 1984. "Report on the Caves and CaveFauna of the Parke, Travis County, Texas." Unpublished Report to the Texas System of Natural Laboratories.

U. S. Fish and Wildlife Service. 1988. "Determination of Five Texas Cave Invertebrates to Be Endangered Species." Federal Register 53: 36029-36033.

U. S. Fish and Wildlife Service. 1994. "Recovery Plan for Endangered Karst Invertebrates in Travis and William Counties, Texas." U. S. Fish and Wildlife Service, Albuquerque, New Mexico.