Volatile secretions and epicuticular hydrocarbons of the beetle Ulomoides dermestoides M. Luciana Villaverde 1 , Juan R. Girotti 1 , Sergio J. Mijailovsky, Nicolás Pedrini, M. Patricia Juárez ⁎ Instituto de Investigaciones Bioquímicas de La Plata (CCT La Plata CONICET-UNLP), Facultad de Ciencias Médicas, calles 60 y 120, 1900 La Plata, Argentina abstract article info Article history: Received 28 January 2009 Received in revised form 10 August 2009 Accepted 11 August 2009 Available online 15 August 2009 Keywords: SPME–CGC Benzoquinone Alkanes Alkadienes DMDS Many species of tenebrionids produce and secrete a defensive volatile blend containing mainly benzoquinones and alkenes. In this study we characterized the volatile organic compounds (VOC) of the beetle Ulomoides dermestoides (Coleoptera: Tenebrionidae). Solid phase microextraction (SPME) coupled to capillary gas chromatography–mass spectrometry (CGC–MS) analysis was used to identify methyl-1,4- benzoquinone (MBQ), ethyl-1,4-benzoquinone (EBQ), 1-tridecene (C 13:1 ), and 1-pentadecene (C 15:1 ), representing more than 90% of the volatile blend. We also used CGC–MS to analyze the epicuticular hydrocarbons of U. dermestoides. Saturated, unsaturated, and branched structures with chain lengths ranging from 13 to 43 carbons were detected. n-pentacosane (C 25:0 ) and 9,11-pentacosadiene (9,11-C 25:2 ) were the most abundant components, representing more than 40% of the cuticular hydrocarbons. © 2009 Published by Elsevier Inc. 1. Introduction Tenebrionid beetles use prothoracic and abdominal glands to pro- duce specific quinone-containing defensive secretions, with repellent and irritant properties against predators (Roth, 1943; Eisner, 1958, 1966; Tschinkel, 1975). Methyl-1,4-benzoquinone (MBQ) and ethyl- 1,4-benzoquinone (EBQ) are the major components (Blum, 1981; Attygalle et al., 1991; 1993; Eisner et al., 1998), usually present together with large amounts of the hydrocarbon 1-pentadecene (C 15:1 )(Wirtz et al., 1978). Whether C 15:1 is originated in the gland, the integument, or both sites remain to be elucidated. The volatile secretions were also reported to have a role in sexual behavior in coleopterans (Peschke and Metzler, 1982; Peschke, 1983; Ruther et al., 2001) and other insects (Holldobler, 1971; Smith et al., 1991). The Oriental tenebrionid Ulomoides dermestoides (Fairmaire) (Coleoptera: Tenebrionidae) was introduced in Brazil by immigrants that use the beetles for treatment of asthma, arthritis, and other diseases (Buzzi and Miyazaki, 1999; Costa-Neto, 2002). U. dermes- toides was reported in Argentina attacking wheat bread and stored wheat grains (Flores et al., 2002), representing a potential pest for stored products. There are no reports on the volatile organic compounds (VOC) of U. dermestoides, although hydroquinone, 2- ethylhydroquinone, and 2-methylhydroquinone with anti-inflamma- tory properties were described for the related tenebrionid Palembus ocularis (Wahrendorf and Wink, 2006). Recently, solid phase micro- extraction (SPME) coupled to capillary gas chromatography (CGC) and mass spectrometry (MS) was used to quantify the relative amounts of VOC components released by the red flour beetle Tribo- lium castaneum, an important pest of grain-based products (Villaverde et al., 2007). Hydrocarbons are the major cuticle surface components in many insect species (Blomquist et al., 1987). Their role in protecting insects from lethal desiccation is widely recognized (Wigglesworth, 1945; Hadley, 1994). They are also the first barrier against chemical or biological contact insecticides (Juárez, 1994; Pedrini et al., 2007), they participate in a variety of chemical communication processes (Blomquist et al., 1993, Lorenzo Figueiras et al., 2009), and were recently related with resistance to chemical insecticides (Pedrini et al., 2009). In tenebrionids, both saturated straight and methyl-branched chains together with unsaturated components were reported in a wide number of species (Lockey, 1988). C 15:1 is the major component of the cuticular hydrocarbons of T. castaneum (Baker et al., 1978). According to their chain length, two major hydrocarbon groups were identified: an unsaturated fraction with chain lengths between 14 and 17 carbons, and a saturated fraction with normal and branched-chain alkanes, ranging from 25 to 35 carbons (Baker et al., 1978). The aim of this study was to characterize both the volatile blend and the epicuticular hydrocarbons of U. dermestoides. 2. Materials and methods 2.1. Insects rearing U. dermestoides was originally obtained from a local market. A six months old colony was maintained at 27 ± 2 °C and 70 ± 5% relative humidity and fed on bran bread supplemented with peanut seeds. Comparative Biochemistry and Physiology, Part B 154 (2009) 381–386 ⁎ Corresponding author. Tel.: +542214824894; fax: +542214258988. E-mail address: mjuarez@isis.unlp.edu.ar (M.P. Juárez). 1 Both authors contributed equally to this work. 1096-4959/$ – see front matter © 2009 Published by Elsevier Inc. doi:10.1016/j.cbpb.2009.08.001 Contents lists available at ScienceDirect Comparative Biochemistry and Physiology, Part B journal homepage: www.elsevier.com/locate/cbpb