P1: GRA Journal of Chemical Ecology [joec] pp1135-481876-07 March 1, 2004 19:54 Style file version June 28th, 2002

Journal of Chemical Ecology, Vol. 30, No. 3, March 2004 (C 2004)

DEFENSIVE CHEMICALS OF TWO SPECIES OF Trachypachus MOTSCHULSKI

ATHULA B. ATTYGALLE,1, XIAOGANG WU,1 JOSEF RUZICKA,1 SHEETAL RAO,1 SILVINA GARCIA,2 KITHSIRI HERATH,2 JERROLD MEINWALD,2 DAVID R. MADDISON,3 and KIPLING W. WILL4

1Department of Chemistry and Chemical Biology Stevens Institute of Technology Hoboken, New Jersey 07030, USA 2Department of Chemistry and Chemical Biology Cornell University Ithaca, New York 14853, USA 3Department of Entomology University of Arizona Tucson, Arizona 85721, USA 4Division of Biology University of California, 201 Wellman Hall Berkeley, California 94720, USA

(Received June 19, 2003; accepted October 30, 2003)

Abstract—Analyses of pygidial gland contents of two species of a previously uninvestigated family of () by Gas Chromatography- Mass Spectrometry (GC-MS) revealed that their chemistry is similar to that reported from many members of the family Carabidae. Nevertheless, the com- position of defensive gland fluids of the two species Trachypachus slevini and T. gibbsii differs sufficiently to distinguish between the two species solely on the basis of their defensive chemistry. The major components of T. slevini glandular fluid are methacrylic, tiglic, and octanoic (= caprylic) acids, together with the hydrocarbon (Z)-9-pentacosene. In contrast, the glandular contents of T. gibbsii contain a rather unique mixture of polar and nonpolar compounds, the princi- pal constituents of which are methacrylic and ethacrylic acids (= 2-ethylacrylic acid), together with 2-phenylethanol, 2-phenylethyl methacrylate, 2-phenylethyl ethacrylate, and (Z)-9-pentacosene.

Key Words—Defensive secretion, methacrylic acid, tiglic acid, octanoic acid, Trachypachidae, Trachypachus slevini, Trachypachus gibbsii.

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0098-0331/04/0300-0577/0 C 2004 Plenum Publishing Corporation