Nitrogen-Containing Compounds in the Scent Gland Secretions of European Cladonychiid Harvestmen (Opiliones, Laniatores, Travunioidea)

Abstract

The exocrine secretions from prominently developed prosomal scent glands in four species of the European laniatorean harvestman genus Holoscotolemon (Laniatores, Travunioidea, Cladonychiidae) were analyzed by gas chromatography – mass spectrometry. Two major alkaloidal compounds were detected: Nicotine accounted for more than 97% of the secretion in Holoscotolemon jaqueti and H. oreophilum, whereas the chemically related nicotinoid alkaloid anabaseine was the major compound in H. lessiniense. In addition, a series of minor nitrogen-containing components was found, namely 3-(1-methyl-2-piperidinyl)-pyridine and anabasine, in H. jaqueti and H. oreophilum, and anabasine together with 2,3′-bipyridyl in H. lessiniense. By contrast, extracts of adult H. unicolor did not show any components. In one juvenile specimen of H. unicolor, however, low amounts of alkyl pyrazines (dimethyl-isobutyl- and dimethyl-isopentylpyrazines) were detected. Nitrogen-containing components previously were found in Sclerobunus robustus (an American travunioid harvestman), so scent gland-derived alkaloids may be widespread or even common in the Travunioidea. Alkaloids have not been reported for other opilionid scent gland secretions outside the Travunioidea, and we hypothesize that they may be the phylogenetically ancestral allomones in the Laniatores, having been reduced and replaced by a phenol- and benzoquinone-rich chemistry in the more derived grassatorean taxa.

Chemosystematics in the Opiliones (Arachnida): a comment on the evolutionary history of alkylphenols and benzoquinones in the scent gland secretions of Laniatores

“…So far, the secretion chemistry in all four opilionid suborders has been exemplarily investigated, revealing sets of naphthoquinones and methyl ketones in the Cyphophthalmi (Raspotnig et al, 2005, naphthoquinones in phalangiid Eupnoi (Wiemer et al, 1978) and in Dyspnoi (Raspotnig et al, 2010), various acycles, including ethyl ketones in sclerosomatid Eupnoi (Ekpa et al, 1985), and volatile ketones in several Dyspnoi (Raspotnig et al, 2014). The chemically best-studied group, however, is certainly the Laniatores, from which at least four major chemical classes of secretion components have been reported: (1) nitrogen-containing compounds including various tobacco alkaloids from travunioid Insidiatores (Raspotnig et al, 2011b), and an array of (2) alkylphenols, (3) benzoquinones and (4) vinyl-ketones from the Grassatores (Roach et al, 1980;Duffield et al, 1981;Eisner et al, 2004;Hara et al, 2005;Wouters et al, 2013). Several authors have hypothesized about the evolutionary history of these compounds, including Hara et al (2005), Raspotnig et al (2011b), Raspotnig (2012) and, recently, Caetano and.…”

“…The chemically best-studied group, however, is certainly the Laniatores, from which at least four major chemical classes of secretion components have been reported: (1) nitrogen-containing compounds including various tobacco alkaloids from travunioid Insidiatores (Raspotnig et al, 2011b), and an array of (2) alkylphenols, (3) benzoquinones and (4) vinyl-ketones from the Grassatores (Roach et al, 1980;Duffield et al, 1981;Eisner et al, 2004;Hara et al, 2005;Wouters et al, 2013). Several authors have hypothesized about the evolutionary history of these compounds, including Hara et al (2005), Raspotnig et al (2011b), Raspotnig (2012) and, recently, Caetano and.…”

Chemical communication and ecology in Eupnoi harvestmen

“…Alkaloids, nicotinoid alkaloid anabaseine and nitrogen-containing components were found in basal groups of cladonychiid harvestmen (Laniatores), and thought to be the ancestral allomones in Laniatores. Then, those compounds were evolutionary "replaced" and reduced by a phenol-and benzoquinone-rich chemistry in derived clades (Raspotnig et al 2011).…”

3‐(2,4‐Dimethoxybenzylidene)‐anabaseine: A promising candidate drug for Alzheimer's disease?

“…They were found in the poison glands of some Insecta Hymenoptera, such as Aphaenogaster 22 and Messor , 23–25 two genera of myrmicine ants where the toxin might serve as a trail pheromone as well 26 . Regarding the class Arachnida, anabaseine has just been found as the major component of the ozopore secretion of Holoscotolemon lessiniense , a Southern Alps harvestman (Opiliones, Laniatores, Travunioidea) 27 . Ozopores (or scent glands) are specific anatomical structures of Opiliones, that act as predator and antimicrobial defense, and can emit pheromons 28 …”

“…26 Regarding the class Arachnida, anabaseine has just been found as the major component of the ozopore secretion of Holoscotolemon lessiniense, a Southern Alps harvestman (Opiliones, Laniatores, Travunioidea). 27 Ozopores (or scent glands) are specific anatomical structures of Opiliones, that act as predator and antimicrobial defense, and can emit pheromons. 28…”