Alkylphenols in the defensive secretion of the nearctic opilionid,Stygnomma spinifera (Arachnida: Opiliones)

Abstract

The opilionid,Stygnomma spinifera, secretes from a pair of exocrine glands on the cephalothorax between the first and second pair of legs a major volatile component, 2-methyl-5-ethylphenol, and two minor components, 2,3-dimethylphenol and 2,3-dimethyl-5-ethylphenol. These alkylphenols are constituents of a defensive secretion and repel ants, a natural predator of opilionids. The probable significance of this secretion in the biology ofS. spinifera and in the defensive strategies of opilionids in general is discussed.

Harvestman Phenols and Benzoquinones: Characterisation and Biosynthetic Pathway

“…The third extender unit loses its labelled carbon, leaving only the non-labelled carbon at C-3. The unexpected enrichment at C-2 is consistent with the incorporation of a propionate unit and the conversion of [1][2][3][4][5][6][7][8][9][10][11][12][13] C]acetate into [1][2][3][4][5][6][7][8][9][10][11][12][13] C]propionate via succinyl-CoA with a methylmalonyl-CoA mutase, as reported for the harvestman I. pustulosa [24]. However, the C 3 label scrambling observed in I. pustulosa was not present in biosynthetic pathway of 7 for Ma.…”

“…Gonyleptid scent gland exudates are mainly composed of vinyl ketones and their hetero-Diels-Alder adducts [3][4][5], alkyl phenols [3,[6][7][8][9][10] and benzoquinones [3,6,[11][12][13][14].…”

“…Before beginning the experiment, a dorso-ventral pressure was applied to all of the individuals to empty their gland sacs. The individuals were divided into two groups and fed with canned dog food containing 5% w/w of the labelled precursors: [1][2][3][4][5][6][7][8][9][10][11][12][13] C]sodium acetate (Cambridge Isotope Laboratories, CIL, Tewksbury, MA, USA) (n = 40 individuals) and [4][5][6][7][8][9][10][11][12][13] C]sodium methylmalonate (for synthetic procedure see [17]) (n = 33 individuals). The control group was the exudate extracted before initiating each experiment (n = 68 individuals).…”

Chemical defense of an opilionid (Acanthopachylus aculeatus)

“…However, 1,4-benzoquinones are not the exclusive defensive compounds of the Laniatores. Some Laniatores produce phenols (Acosta et al, 1993;Eisner et al, 1977;Duffield et al, 1981), and one other, the Uruguayan Parampheres ronae, produces a mixture of vinyl alkyl ketones (C. Rossini, unpublished observation). The members of the second principal suborder of the opilionids, the Palpatores, produce an array of volatile branched-chain alcohols, ketones and aldehydes Ekpa et al, 1985).…”

Estudo comparado da morfologia da região do ozóporo de opiliões Laniatores (Arachnida, Opiliones)

“…Hara & Gnaspini (2007) sintetizaram muitos dos vários estudos de tais métodos de defesa no grupo em questão. Entretanto, cabem ainda algumas poucas adições a tal resumo: os comportamentos de se retrair em algum local protegido frente a potencial presença de um predador, jogar-se no chão permanecendo imóvel, objetivando passar despercebido também foram observados em Stygnomma spinifera, por Duffield et al (1981). Gonisosoma catarina vem corroborar a afirmação de que os machos adultos da subfamília Goniosomatinae aplicam o movimento de pinça, o "beliscão", utilizando-se das armaduras do fêmur IV, visto que também se utilizam de tal mecanismo .…”