Identification of defensive compounds in metathoracic glands of adults of the stink bug Dichelops melacanthus (Hemiptera: Pentatomidae)

Abstract

Os conteúdos das glândulas metatorácicas de insetos adultos do percevejo Dichelops melacanthus (Hemiptera: Pentatomidae) foram analisados. Os compostos de defesa foram identificados combinando as técnicas de cromatografia gasosa (CG), cromatografia gasosa acoplada à espectrometria de massas (CG-EM) e por comparação de seus índices de retenção com os de compostos padrões. Tridecano foi o componente majoritário, seguido de quantidades menores e aproximadamente iguais de (E)-4-oxo-2-hexenal e (E)-2-octenal. Também foram identificados (E)-2-hexenal, decano, acetato de (E)-2-hexenila, undecano, (E)-4-oxo-2-octenal, dodecano, acetato de (E)-2-octenila, 1-trideceno, tetradecano e pentadecano.The contents of metathoracic glands of adults of the stink bug Dichelops melacanthus (Hemiptera: Pentatomidae) were analyzed. Compounds were identified by gas chromatography (GC), coupled GC-mass spectrometry and matching retention indices and mass spectra with those of authentic samples. Tridecane was the major component followed by lesser and approximately equal amounts of (E)-4-oxo-2-hexenal and (E)-2-octenal. Other compounds identified include (E)-2-hexenal, decane, (E)-2-hexenyl acetate, undecane, (E)-4-oxo-2-octenal, dodecane, (E)-2-octenyl acetate, 1-tridecene, tetradecane and pentadecane.Keywords: Dichelops melacanthus, defensive compounds, short-chain unsaturated aldehydes, unsaturated acetates, tridecane IntroductionInsects have evolved a multitude of chemical and behavioral defenses against other offensive organisms. Stink bugs, as their name suggests, produce large quantities of strong-smelling and irritating defensive chemicals, which are released when the bugs are disturbed or molested. 1In general, heteropterans produce allomones in dorsal abdominal scent glands as immatures, and in metathoracic scent glands as adults. [1][2][3] Numerous reports attest to the efficacy of the secretions of the metathoracic and abdominal scent glands as effective defenses against predation. 1,2,4 They also may have a role as alarm pheromones, 5 as has been demonstrated for similar types of compounds produced by bug species in other families. 6,7 Stink bug defensive compounds have received considerable study, and it has been shown that the types of compounds constituting the defensive chemical blends typically consist of alkane hydrocarbons and saturated and unsaturated aldehydes and esters. In adults, the defensive compounds are produced in large, well-defined, and usually colored metathoracic glands, which are not present in the immature stages.Sex pheromones have been identified from only a few phytophagous stink bug species to date. 8,9 In all cases reported, components from metathoracic glands have not been part of the pheromone blend. However, because stink bugs readily release defensive compounds when disturbed, it is difficult if not impossible to collect extracts of sex pheromones uncontaminated by these components.The main objective of this study was to characterize the defensive compounds produced in the metathoracic glands o...

Profiling and characterization of volatile secretions from the European stink bug Graphosoma lineatum (Heteroptera: Pentatomidae) by two-dimensional gas chromatography/time-of-flight mass spectrometry

“…Of the 57 compounds identified in this study, the compounds previously detected in G. lineatum secretions include some n-alkanes, alk-2-enals, alk-2-enols, alk-2-enyl acetates and limonene [8][9][10]. These compounds, along with some dienal isomers [44,45] and other compounds, such as e.g. (E)-hex-2-enyl butyrate, tridec-1-ene [44], 3-methyltridecane, cyclohexane-1,4-dione [46] and even (E)-4-oxohex-2-enal [6,[47][48][49], were also occasionally found in other heteropteran bug families [50][51][52].…”

“…These compounds, along with some dienal isomers [44,45] and other compounds, such as e.g. (E)-hex-2-enyl butyrate, tridec-1-ene [44], 3-methyltridecane, cyclohexane-1,4-dione [46] and even (E)-4-oxohex-2-enal [6,[47][48][49], were also occasionally found in other heteropteran bug families [50][51][52]. However, only approximately one third of the volatiles listed in Table 1 have been previously reported as constituents of G. lineatum secretions, while 39 (Table 1, compounds in bold) of the 57 identified volatiles are reported here for the first time.…”

“…i Ref. [44] reports a LRI value of 976 measured on a CP Sil 8 column. Table 1. the first dimension (non-polar column) and was only partly separated in the second dimension (polar column), clear spectra of both compounds were obtained by applying ChromaTOF software deconvolution procedure (Fig.…”

Hydrolysis of methyl benzoate from Piper arboreum by Naupactus bipes beetle

“…4,5 The function of plant secondary metabolites in mediating insect-plant interactions has been addressed in several studies 6,7 and more recently, the specificity of Piper-insects relationship and the metabolism of secondary compounds by herbivorous insects has been investigated. 8,9 Herein, we describe the hydrolysis of methyl benzoic acid derivative 1 to 3-geranyl-4-hydroxybenzoic acid (2) during the digestive process of P. arboreum leaves by N. bipes beetles.…”

Identificação e análise computacional de transcritos relacionados à olfação em espécies de percevejos praga da soja

“…melacanthus, sendo os voláteis identificados associados à defesa desses insetos (Marques et al, 2007;Pareja et al, 2007).…”