High Conservatism in the Composition of Scent Glan

Authors: Günther Raspotnig Julia Schwab Ivo Karaman

Publish Date: 2012/04/04

Volume: 38, Issue: 4, Pages: 437-440

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Abstract

The scent gland secretion of Austropurcellia forsteri was analyzed by gas chromatography–mass spectrometry providing the first description of the secretion chemistry in the cyphophthalmid family Pettalidae The secretion contained a total of 21 compounds About 60 of the whole secretion consisted of a series of saturated monounsaturated and doubly unsaturated methylketones from C11 to C15 with a cluster of saturated and monounsaturated C13methylketones dominating A second fraction included several naphthoquinones such as 14naphthoquinone ca 20 of secretion 6methyl14naphthoquinone ca 17 and minor amounts of chloronaphthoquinones ca 2 When compared with scent gland compositions of other representatives of cyphophthalmids eg from families Sironidae and Stylocellidae a highly conservative chemistry of cyphophthalmid secretions is apparent based on a restricted number of methylketones and naphthoquinonesThe Cyphophthalmi represent the smallest suborder of harvestmen currently comprising about 190 described species in six families Giribet et al 2012 Like all harvestmen the Cyphophthalmi possess prosomal defensive “scent” glands which are strikingly developed across this suborder When a leg is grasped by forceps many if not all cyphophthalmid species expel droplets of scent gland secretion from dorsolaterally protruding ozophores dab each droplet with the tip of one leg mostly leg II and transfer the secretion to the forceps This behavior has been described as “leg dabbing” and it clearly identifies cyphophthalmid scent gland secretions as defensive Juberthie 1961 The chemistry of cyphophthalmid secretions however has been poorly studied Raspotnig et al 2005 reported on secretions of two species of the family Sironidae Cyphophthalmus duricorius from Europe and Siro exilis from USA and Jones et al 2009 studied the chemistry of an undescribed Sulawesian stylocellid All three species produce multicomponent secretions that although distinguishable are based on common chemistry of acyclic methylketones and naphthoquinones No chemical analyses on the secretions of other cyphophthamid species have been performedTwelve adults 5 males 7 females and 6 juvenile specimens of Austropurcellia forsteri Juberthie 2000 Pettalidae were collected from leaf litter at Cape Tribulation Queensland Australia This species originally included within the genus Neopurcellia by Juberthie 2000 has been transferred to the genus Austropurcellia on the basis of molecular data Boyer and Giribet 2007 and is considered to represent a member of a monophyletic clade of pettalids in the northeast of Australia Species determination was performed by the original description of Juberthie 2000Scent gland secretions were obtained either by dabbing secretion from ozopores on filter paper or by whole body extraction of single individuals Extracts were analyzed by gas chromatography–mass spectrometry GCMS using a Trace GC2000 with a ZB5 capillary column 30 m x 025 mm id x 025 μm film thickness and helium at 12 mlmin1 coupled to a DSQ MS ion source at 200°C transfer line at 310°C The temperature of the GC oven was programmed from 50°C 1 min delay to 300°C at 10°Cmin1 then 5 min at 300°C Areas of individual peaks were integrated and expressed as peak area of a whole extractCompounds were identified by comparison of mass spectral and gas chromatographic data to synthetic standards and by comparison to already identified components in Cyphophthalmus extracts Raspotnig et al 2005 Synthetic 14naphthoquinone undecan2one dodecan2one and tridecan2one were purchased from Sigma Vienna Austria and 4chloro14naphthoquinone was synthesized as described in Raspotnig et al 2005 As a reference source for 6methyl14naphthoquinone we used the scent gland secretion of Phalangium opilio Wiemer et al 1978

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