Final Report Examining the Role of Cave Crickets (Rhaphidophoridae) in Central Texas Cave Ecosystems: Isotope Ratios (δ13C, δ15N) and Radio Tracking Steven J. Taylor1, Keith Hackley2, Jean K. Krejca3, Michael J. Dreslik 1, Sallie E. Greenberg2, and Erin L. Raboin1 1Center for Biodiversity Illinois Natural History Survey 607 East Peabody Drive Champaign, Illinois 61820 (217) 333-5702
[email protected] 2 Isotope Geochemistry Laboratory Illinois State Geological Survey 615 East Peabody Drive Champaign, Illinois 61820 3Zara Environmental LLC 118 West Goforth Road Buda, Texas 78610 Illinois Natural History Survey Center for Biodiversity Technical Report 2004 (9) Prepared for: U.S. Army Engineer Research and Development Center ERDC-CTC, ATTN: Michael L. Denight 2902 Newmark Drive Champaign, IL 61822-1076 27 September 2004 Cover: A cave cricket (Ceuthophilus The Red Imported Fire Ant (Solenopsis secretus) shedding its exuvium on a shrub (False Indigo, Amorpha fruticosa L.) outside invicta Buren, RIFA) has been shown to enter and of Big Red Cave. Photo by Jean K. Krejca. forage in caves in central Texas (Elliott 1992, 1994; Reddell 2001; Reddell and Cokendolpher 2001b). Many of these caves are home to federally endangered invertebrates (USFWS 1988, 1993, 2000) or closely related, often rare taxa (Reddell 2001, Reddell and Cokendolpher 2001a). The majority of these caves are small – at Fort Hood (Bell and Coryell counties), the mean length1 of the caves is 51.7 m (range 2.1 - 2571.6 m, n=105 caves). Few of the caves harbor large numbers of bats, perhaps because low ceiling heights increase their vulnerability to depredation by other vertebrate predators (e.g., raccoons, Procyon lotor).