Differences in Defensive Volatiles of the Forked Fungus Beetle, Bolitotherus cornutus, Living on Two Species of Fungus

Abstract

Forked fungus beetles, Bolitotherus cornutus, feed, mate, and live on the brackets of several species of shelf fungus that grow on decaying logs. In response to the specific threat stimulus of mammalian breath, B. cornutus beetles produce a volatile defensive secretion. We tested beetles collected from different host fungi to determine whether defensive secretion blends varied with host type. Using solid phase microextraction and gas chromatographymass spectrometry, we detected large amounts of the alkylated benzoquinones, methyl-p-benzoquinone (toluquinone) and ethyl-p-benzoquinone, and smaller quantities of p-benzoquinone, 3-methylphenol (m-cresol), 3-ethylphenol, 2-methylhydroquinone, and 2-ethylhydroquinone in secretions. Volatile composition did not differ between male and female beetles. Secretions did differ between beetles collected from two species of fungus, Ganoderma applanatum and Fomes fomentarius, with the relative amount of pbenzoquinone secreted being the most important factor. Other relationships among the volatile components are discussed.

Defensive Secretions of the Carabid Beetle Chlaenius cordicollis: Chemical Components and their Geographic Patterns of Variation

“…However, at least some of the negative correlations with 3-methylphenol may be artifacts; when the relative peak area of 3-methylphenol is close to 100%, addition of a small percentage of another alkylphenol must perforce diminish the value for 3-methylphenol and create a negative association. Unlike the negative correlation we observed between 3-methylphenol and 3-ethylphenol in C. cordicollis, these compounds are positively correlated in the tenebrionid beetle Bolitotherus cornutus (Panzer) (Holliday et al, 2009).…”

“…However, they, like we, cannot disprove the hypothesis that geographic variation in defensive secretions is attributable to different precursors in food consumed by insects in the field. For example, the composition of defensive secretions of fungusfeeding tenebrionid beetles is food-dependent (Holliday et al, 2009), and the seasonal variation in defensive secretions in a predatory dytiscid beetle may reflect the availability of plantsynthesized precursors acquired by herbivore prey (Miller and Mumma, 1974). The assemblage of insects available for C. cordicollis to scavenge no doubt differs between the banks of the Delaware River and the beaches of Lake Winnipeg, and we expect the available dietary precursors of phenolic compounds to differ between our source localities.…”

“…For example, the prothoracic defensive secretion of Zophobas rugipes Kirsch is 97% 3-methylphenol and 2% 3-ethylphenol (Tschinkel, 1969). Smaller quantities (<10%) of these two compounds have been reported in defensive secretions of at least seven other species of tenebrionids (Geiselhardt et al, 2009;Holliday et al, 2009), as well as in the sex pheromones of the tenebrionid, Parastizopus armaticeps Peringuey (Geiselhardt et al, 2008).…”

Biosynthesis of Firefly Luciferin in Adult Lantern: Decarboxylation of ʟ-Cysteine is a Key Step for Benzothiazole Ring Formation in Firefly Luciferin Synthesis

“…It is known that quinones including p -benzoquinone and its derivatives are found in some beetles (Coleoptera) [22]–[24] and p -benzoquinone is a metabolite produced by the oxidation of 1,4-hydroquinone [25]. Because p -benzoquinone shows high toxicity to living organisms, the concentration of p -benzoquinone was 10-fold lower than that of 1,4-hydroquinone in our injection experiments.…”

Harvestman Phenols and Benzoquinones: Characterisation and Biosynthetic Pathway

“…Eisner and co-workers reported that benzoquinone 9 and phenol 21 from Zygopachylus albimarginis (Manaosbiidae) [6] had the same biosynthetic origin for both components. The production of benzoquinones, hydroquinones and phenols by the forked fungus beetle Bolitotherus cornutus also suggests that the alkyl benzoquinones and alkyl phenols might share a similar biosynthetic origin [36]. Scheme 2.…”