Bee Creek Cave Harvestman

Texella reddelli

Description

Harvestmen are anatomically and evolutionarily quite distinct from spiders. The eyeless Bee Creek Cave harvestman, Texella reddelli, has a pale yellow-brown body, barely 0.13 in (0.33 cm) in length, with relatively long legs. It has well-developed eyes set in broadly conical eye mounds. Juveniles are white to yellowish-white. It is similar in appearance to the common daddy long-legs. It uses its two front legs, which are longer than the others, to feel its way through its lightless habitat. T. reddelli can be distinguished in the field from its closest relative, T. reyesi by its shorter legs, its well developed eyes, and its color, which is more orange.

Behavior

Little is known of this cave dweller's behavior and reproductive activity. It is probably predatory, feeding on other insects.

Habitat

The Bee Creek Cave harvestman is restricted to five, dry limestone caves.

Distribution

This harvestman is an example of a localized cave fauna found in Travis and Williamson Counties, Texas. It has been collected from five caves in the region and is suspected to occupy a sixth.

The size of the Bee Creek Cave harvestman population has not been estimated, but the U. S. Fish and Wildlife Service (FWS) biologists believe that the species may be more limited in numbers than previously thought. This spider has been collected from Tooth, Bee Creek, McDonald, Weldon, and Bone Caves. In 1984, it was reported from Root Cave in Travis County, but its presence there has not been confirmed.

Threats

In recent years, the suburbs of the city of Austin have expanded into Travis and Williamson Counties, causing the loss of many caves and natural sinkholes. Land-clearing, digging, and blasting have caused collapsed caves or buried the entrances. Weldon Cave—site of a past biological survey—lay along the path of a recent road expansion and may no longer exist. Coffin Cave also appears to have succumbed to bulldozing in 1988. New roads in the area have stimulated construction of subdivisions closer to the main caves of the system—Tooth, McDonald, and Root Caves. The subdivisions and other construction projects, such as a proposed pipeline, are expected to alter drainage patterns and degrade the quality of the groundwater on which the cave species depends.

Conservation and Recovery

Protection of the harvestman requires the creation of sufficient easements around the caves to prevent physical disturbance or pollution of groundwater. Human intrusion and habitat disturbance also must be discouraged. Endemic cave species are also covered in the 1991 FWS Recovery Plan for the black-capped vireo (Vireo atricapillus ), which nests in the area.

Contact

Regional Office of Endangered Species
U.S. Fish and Wildlife Service
P. O. Box 1306
Albuquerque, New Mexico 87103
http://southwest.fws.gov/

References

Goodnight, C. J., and M. L. Goodnight. 1967. "Opilionids from Texas Caves (Opiliones Phalangodidae)," American Museum Novitates 2301.

Reddell, J. 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.