Chemical composition and pheromonal function of the defensive secretions in the subtribe Stizopina (Coleptera, Tenebrionidae, Opatrini)

Abstract

The chemical composition of the defensive secretions of 52 species from 15 genera of the tenebrionid subtribe Stizopina was analyzed. The secretions of all species contained 1,4-benzoquinones, 1-alkenes, and monoterpene hydrocarbons, only one species was lacking the latter. Methyl-and ethyl-1,4-benzoquinone were ubiquitous, mostly accompanied by smaller amounts of 1,4-benzoquinone as well as isopropyl-and propyl-1,4-benzoquinone. 1-Alkenes were dominated by 1-undecene with varying admixtures of other 1-alkenes. The monoterpene hydrocarbons always consisted of a mixture of a-pinene, camphene, b-pinene and limonene, but also p-cymene, a-terpinene or a-phellandrene were found in some species. Furthermore, some species synthesized additional compounds such as phenols, ketones, 2,5-dihydroxy-6-methylbenzoate, 2-hydroxy-4-methoxyacetophenone and naphthoquinones. Bioassays showed that the defensive secretion co-functioned as an aggregation pheromone in the subtribe Stizopina. All nine tested species from six genera were attracted to defensive secretion of Stizopina species, but they did not distinguish between defensive secretions of different Stizopina species. This lack of discrimination might be the initial step for the formation of interspecific aggregations and the evolution of cleptoparasitism within the Stizopina.

Volatile compounds emitted by Triatoma dimidiata, a vector of Chagas disease: chemical analysis and behavioural evaluation

“…Several compounds used as sex pheromones by beetles of the subfamily Melolonthinae have antimicrobial activity against bacteria and fungi, which indicates that these compounds may have taken on a secondary function as sex pheromones (Leal, 1997). The primary function of the secretion of the pygidial gland of beetles of the subtribe Stizopina is to deter predators, but in addition, the secretion also functions as an aggregation pheromone (Geiselhardt et al , 2009).…”

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

“…3-Methylphenol (Tschinkel 1969;Attygalle et al 1991;Villaverde et al 2007;Geiselhardt et al 2009;), 3-ethylphenol (Tschinkel 1969;Geiselhardt et al 2009), 2-methylhydroquinone (Happ 1968;Wahrendorf and Wink 2006;Villaverde et al 2007;Geiselhardt et al 2009), and 2-ethylhydroquinone (Happ 1968;Hodges et al 1996;Wahrendorf and Wink 2006;Geiselhardt et al 2009) have all been detected in the defensive secretions of other tenebrionid beetles, although quinones are more ubiquitous 3-Methylphenol, 2-methylhydroquinone, and methyl-pbenzoquinone are thought to be sequential members of a biosynthetic pathway that originates with 6-methylsalicylic acid (Gnanasunderam et al 1984), itself formed from acetate (or malonate) units (Birch et al 1955). Similarly, 3-ethylphenol, 2-ethylhydroquinone, and ethyl-p-benzoquinone are likely derived from 6-ethylsalicylic acid (Gnanasunderam et al 1984), which differs in its synthesis by the use of a propionate unit in place of an acetate (or malonate) unit, as evidenced by isotope tracing experiments on ethyl-pbenzoquinone (Meinwald et al 1966).…”

The origin and dynamic evolution of chemical information transfer

“…Exaptations of defensive substances also occur in insects where they have been co-opted to function as sex, aggregation, alarm or trail pheromones (e.g. [34][35][36][37]). For example, various eusocial Hymenoptera emit alarm pheromones, sex pheromones and components of trail pheromones from the venom gland, which primarily functions as reservoir for defensive substances [34,38].…”