Chemical defenses in the opilionid infraorder Insidiatores: divergence in chemical defenses between Triaenonychidae and Travunioidea and within travunioid harvestmen (Opiliones) from eastern and western North America

• Published in: The Journal of arachnology 2014-11, Vol.42 (3), p.248-256
• Main Authors: Shear, W. A., Jones, T. H., Guidry, H. M., Derkarabetian, S., Richart, C. H., Minor, M., Lewis, J. J.
• Format: Article
• Language: English
• Subjects: 2-3′ dipyridyl; 4-methyl-3-hexanone; Animal defenses; benzothiazole; FEATURED ARTICLES; Harvestmen; Health aspects; mellein; N,N-dimethylphenylethylamine; Nicotine; salicyl alcohol; Zoological research
• ISSN: 0161-8202; 1937-2396
• DOI: 10.1636/B14-41.1

Live whole specimens of two species of the harvestman Superfamily Travunioidea Absolon & Kratchovíl 1932 from the eastern United States, eight species from the western United States, six morphospecies of the family Triaenonychidae Sørensen 1886 from New Zealand, and specimens of the phylogenetically early-diverging North American triaenonychid Fumontana deprehendorShear 1977 were extracted in methanol, and the solvent analyzed for components from their defensive secretions. The components were then mapped on a recent phylogeny of the taxa. In both eastern cladonychiid species, Erebomaster flavescens Cope 1872 and Theromaster brunneus (Banks 1902), the major component found was anabaseine, an alkaloid related to nicotine. In the western species, Paranonychus brunneus (Banks 1893), Cryptomaster leviathan Briggs 1969, Speleomaster lexi Briggs 1974, S. pecki Briggs 1974, Speleonychia sengeri Briggs 1974, Metanonychus idahoensis Briggs 1971, Briggsus flavescens (Briggs 1971) and Sclerobunus nondimorphicus Briggs 1971, the major component was N,N-dimethylphenylethylamine, implying that the travunioids from the two regions represent different phyletic lines. The secretions of the triaenonychid species, members of the genera Soerensenella Pocock 1903 and Nuncia Loman 1902, were dominated by 4-methyl-3-hexanone, and that of F. deprehendor by phenol. The completely different chemistry of the two taxa, Travunioidea and Triaenonychidae, implies significant phylogenetic differences, and the presence of phenol in F. deprehendor may suggest a long period of separate evolution for this species.