Chemical defense in Tetracion 153

International Journal of Myriapodology 3 (2010) 153-158 Sofi a–Moscow

Chemical defense of a troglobiont , Tetracion jonesi Hoff man (Diplopoda, Callipodida, )

William A. Shear1, Iain S. McPherson 2, Tappey H. Jones2, Stephanie F. Loria3 & Kirk S. Zigler3 1Department of Biology, Hampden-Sydney College, Hampden-Sydney VA 23943 USA, E-mail: ws- [email protected] 2Department of Chemistry, Virginia Military Institute, Lexington, VA 24450 USA, E-mails: jonesth@ vmi.edu, [email protected] 3Department of Biology, University of the South, Sewanee, TN 37383 USA, E-mails: kzigler@sewanee. edu; [email protected]

Abstract Tetracion jonesi Hoff man, 1956 is a troglomorphic cave-limited abacionid milliped found in caves in the southern Cumberland Plateau of Alabama and Tennessee, USA. Specimens collected in a cave in Franklin Co., Tennessee, were live-extracted with methanol. Gas chromatography/mass spectroscopy of the extract revealed p-cresol as the sole component of the milliped’s chemical defense. Th ree other callipodidan spe- cies have been studied and also produce p-cresol.

Key words p-cresol, troglobiosis, , Alabama, Tennessee, caves

Introduction Tetracion jonesi Hoff man, 1956 (Fig. 1) has been the subject of ongoing genetic research by SFL and KSZ. Th is abacionid milliped, found exclusively in caves in the Cumberland Plateau of Alabama and Tennessee, USA, is one of the three troglobi- otic and troglomorphic of Tetracion, a genus endemic to the Cumberland Plateau (Hoff man 1956). As with all callipodidan millipeds so far studied, T. jonesi carries obvious paired lateral repugnatorial glands on all diplosegments from the

© Koninklijke Brill NV and Pensoft, 2010 DOI: 10.1163/187525410X12578602960588 154 William A. Shear et al. / International Journal of Myriapodology 3 (2010) 153-158

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Figure 1. Male Tetracion jonesi Hoff man, showing ozopores (p) starting on the sixth trunk segment. sixth to the penultimate. Th e glands open through pores (p, Fig. 1) located on a dorsolateral metazonital crest, which is signifi cantly broader than the others to accommodate the pore. Th e chemical identity of the product of these glands was suspected, on the basis of previous work on other species belonging to the families Abacionidae and , to contain p-cresol. Both Peck (1989) and Shear et al. (2007) have cited unpublished data by M. Blum identifying p-cresol as a com- ponent of the secretion. Below we confi rm by our own analysis that p-cresol is the sole volatile compound identifi able in whole-body methanol extracts of Tetracion jonesi individuals.