Ulomoides dermestoides (Fairmaire, 1893) is an Asiatic insect used for medicinal purposes all over the world. In Brazil, people buy these insects in animal product stores not only to feed birds and fish, but also as alternative medication for asthma and arthritis. The aqueous extract of U. dermestoides has been demonstrated to have an anti-inflammatory activity in rats (Santos et al. 2010), which supports popular medicinal usages. Recently, Villaverde et al. (2009) identified or ganic volatile compounds released by U. dermes toides, such as methyl-1,4-benzoquinone, ethyl 1,4-benzoquinone, 1-tridecene, and 1-penta decene, which represent more than 90% of the volatile blend. The volatile collection was carried out by SPME, and no sex specific compound was detected. We worked with the same species and collected the volatiles produced by groups of 300 males and females, separated by sex, for 96 h in glass aeration chambers (33 cm height by 4.5 cm outside diameter) with 1 broken peanut inside of each chamber. The volatiles emitted were trapped on 0.8 g of Super Q (Alltech, Deerfield, IL) col umns as previously reported (Zarbin et al. 2003). Five repetitions were performed. The same meth odology was used for a 12-h photo-scotophase aer ation collection. Volatiles were eluted from Super Q with 4 mL of distilled hexane and concentrated to 600 pL (1 insect per 2 pL) under an argon stream (Ambrogi et al. 2009), and 1 pL was in jected in a GC-MS system (QP-2010 Plus, Shi madzu). Bioassays for these extracts were based on the protocol of Suzuki & Sugawara (1979). The re sponses of 3 virgin males or females to aeration extracts from both males and females were tested. Filter papers cut to 2 cm 1 cm were im pregnated with 5 pL of extract (2.5 IE) and placed on each side of a Petri dish (9 cm of diameter) for 20 min. Twenty repetitions were performed for each test, and the presence of insects on the filter paper was considered a positive response. The statistical analyses were performed by BioStat 3.0 (Ayres et al. 2003) with paired ?-test and 95% significance. Beetles were purchased in a local store and maintained inside a plastic box with peanuts at room temperature with a photo period of 12:12 (L:D). Pupae were sexed and placed in plastic containers, and emerged adults were fed with peanuts. Behavioral bioassays revealed statistically sig nificant preferences of females and males to male extracts (t = 1.972* and = 0.032*; t = 3.824** and = 0.0007**, respectively) versus female ex tract. The Chromatographie profiles of volatiles from male and female U. dermestoides are shown in Fig. 1 and clearly indicate the existence of 3 male-specific compounds (a-c). GC-MS investiga tion provided analytical data and a fragmenta tion pattern that strongly suggested compounds -c to be hydrocarbon-sesquiterpenes (C15H24). The CG-MS data with retention time (RT) and Kovat's Index (KI) for these compounds were as follows: (a) RT = 16.20 min; KI = 1,422 (DB-5); ml (%): 204 (M+; 26.78), 189 (11.46), 161 (7.72), 136 (100), 121 (92.69), 107 (59.68), 93 (68.1); (b) RT = 16.24 min; KI = 1,423 (DB-5); ml (%): 204 (M+; 13.73), 189 (4.25), 161 (38.21), 147 (5.85), 136 (23.66), 121 (51.1), 119 (100), 105 (96.83); and (c) RT = 16.30 min; KI = 1,426 (DB-5); m I (%): 204 (M+; 18.92), 161 (20.59), 147 (10.18), 121 (14.17), 119 (100), 105 (34.58), 93 (36.37). The identifica tion of the other 6 compounds (1-6) present in both sexes (Fig. 1) was based on the fragmenta tion pattern of the GCLMS analysis and NIST li brary suggestion and was in accordance with the components previously reported by Villaverde et al. (2009). The 6 identified compounds were me thyl-1,4-benzoquinone (1), limonene (2), ethyl 1,4-benzoquinone (3), 1-tridecene (4), pentadeca diene (5), and 1-pentadecene (6), in a ratio of 5: 9.2: 45.2: 6.2:1:123.2, respectively. Villaverde et al. (2009) agitated the vials where the volatiles were collected and detected ethyl-1,4-benzoquinone as the major compound; however, in our study, pentadecadiene had the highest concentration. Because qui?ones are common defensive compounds produced by tene brionid beetles (Brown et al. 1992) when dis turbed, the major peak difference is justified. Our findings provide evidence that the aggre gation observed in U. dermestoides is mediated by a putative pheromone attracting both sexes and produced by males. The 12-h aeration revealed the continuous production of these 3 putative ses quiterpenes during photoand scotophase, sup
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Jul 1, 2022
Matthew Bowman + 1
Open Access