High Conservatism in the Composition of Scent Gland Secretions in Cyphophthalmid Harvestmen: Evidence from Pettalidae

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, mono-unsaturated and doubly unsaturated methylketones, from C11 to C15, with a cluster of saturated and mono-unsaturated C13-methylketones dominating. A second fraction included several naphthoquinones such as 1,4-naphthoquinone (ca. 20% of secretion), 6-methyl-1,4-naphthoquinone (ca. 17%), and minor amounts of chloronaphthoquinones (ca. 2%). When compared with scent gland compositions of other representatives of cyphophthalmids (e.g. from families Sironidae and Stylocellidae), a highly conservative chemistry of cyphophthalmid secretions is apparent, based on a restricted number of methylketones and naphthoquinones

On the enigmatic scent glands of dyspnoan harvestmen (Arachnida, Opiliones): first evidence for the production of volatile secretions

La utilización en encuestas de preguntas con tarjetas de respuesta está totalmente aceptada por la comunidad investigadora. Esto supone una carga de trabajo “extra” en la tarea del entrevistador, lo que explica que en ocasiones no se utilicen correctamente. Pese a esta situación, hay muy poca literatura sobre la influencia de las tarjetas en las respuestas del entrevistado. El objetivo de este trabajo es profundizar en los efectos que la utilización de tarjetas tiene en la calidad de las respuestas del cuestionario, partiendo de la hipótesis que considera que las tarjetas —pese a complicar la tarea del encuestador— suponen importantes mejoras en la administración del cuestionario. Utilizaremos para ello un estudio del Centro de Investigaciones Sociológicas con 23 preguntas de tarjeta, comparando las respuestas de los entrevistados que utilizaron las tarjetas con aquellos que no las emplearon.Using “response cards” in question surveys is unanimously approved by the research community. The fact that this represents an extra workload for the interviewer’s task explains why they sometimes are not used correctly. Despite this situation there is a paucity of literature on the influence of the response card on the respondent’s answers. The aim of this study is to deepen the analysis of how using these cards affect the quality of the survey’s responses. To do so, we start from the assumption that the cards —while complicating the interviewer’s task, result in significant improvements in the survey’s administration. For this purpose we will use a study with 23 card questions (question cards) by the Centro de Investigaciones Sociológicas, (the Spanish Centre for Sociological Research), and we will compare the answers of respondents that used cards with those who did not

How many species of mite-harvestmen (Opiliones, Cyphophthalmi) are there in Austria?

Der bodenbewohnende Milbenkanker Cyphophthalmus duricorius Joseph, 1868 (Fam. Sironidae) galt mehr als 60 Jahre lang als die einzige in Österreich vorkommende Art der Weberknecht-Unterordnung Cyphophthalmi. Neuere Aufsammlungen zeigen jedoch, dass mindestens zwei weitere Cyphophthalmi-Arten in Österreich existieren: 1) Siro cf. crassus Novak & Giribet, 2006 wurde an einer Lokalität in der SW Steiermark nahe der slowenischen Grenze gefunden und repräsentiert eine zweite Gattung von Sironiden in Österreich. 2) Ein weiterer, morphologisch distinkter Sironide („Sironidae gen. et sp. nov.?“) − derzeit noch unbeschrieben und taxonomisch nicht zugeordnet − stammt aus Böden im Grenzgebiet Steiermark-Kärnten. Obwohl bislang kein syntopes Vorkommen belegt ist, können alle drei Arten in einem kleinen Areal von wenigen Quadratkilometern gefunden werden.For the last 60 years, the mite-harvestman Cyphophthalmus duricorius Joseph, 1868, a soil-dwelling sironid, has been considered to be the only representative of the opilionid suborder Cyphophthalmi in Austria. However, novel data from recent collections confirm the presence of at least two further Austrian cyphophthalmid species. (1) Siro cf. crassus Novak & Giribet, 2006 occurs in at least one location in SW Styria near the Slovenian border and hence represents a member of a second genus of Austrian sironids. (2) A further morphologically distinct sironid (“Sironidae gen. et sp. nov.?”) – so far undescribed and systematically not placed in detail – was collected in the borderland between Styria and Carinthia. All three species can be found in a small area of a few square-kilometers; although no syntopic occurrence was recorded

Alkaloids from millipedes: a re-evaluation of defensive exudates from Polyzonium germanicum

Millipedes are known to produce various sets of chemical compounds in exocrine defensive glands to protect themselves against predators and microorganisms. Here, we reanalyzed the gland secretion of Polyzonium germanicum, a millipede of the order Polyzoniida, by using a combination of analytical techniques such as GC-MS, LC-HRMS and high field 1D and 2D NMR spectroscopy. Previously only one compound (polyzonimine, 1) had been described, but our approach allowed us to add six compounds to the defensive chemistry of this species. Besides polyzonimine (1), we found nitropolyzonamine (2) and five new compounds: 3 (2,3-dimethyl-7’-nitro-2’,3’,5’,6’,7’,7a’-hexahydrospiro[cyclopent-2-ene-1,1’-pyrrolizine]), 4 (2,3-dimethyl-7’-nitro-2’,3’,5’,6’,7’,7a’-hexahydrospiro[cyclopentane-1,1’-pyrrolizin]-2-ene), 5 ((1Z)-8,9-dimethyl-1-(nitromethylidene)-2-azaspiro[4.4]non-8-en-7-one), and not fully identified compounds A, B. For compounds 3–5 we were able to determine the molecular constitution, for two of them (4, 5) we were able to give relative configurations. Overall, the combination of advanced analytical techniques applied herein allowed detailed insights into the defensive chemistry of P. germanicum with a low number of individuals needed for analysis and without prior compound isolation

A Novel Class of Defensive Compounds in Harvestmen: Hydroxy-γ-Lactones from the Phalangiid Egaenus convexus

When threatened, the harvestman Egaenus convexus (Opiliones: Phalangiidae) ejects a secretion against offenders. The secretion originates from large prosomal scent glands and is mainly composed of two isomers of 4-hydroxy-5-octyl-4,5-dihydro-3H-furan-2-one (1), a β-hydroxy-γ-lactone. The compounds were characterized by GC-MS of their microreaction derivatives, HRMS, and NMR. After the synthesis of all four possible stereoisomers of 1, followed by their separation by chiral-phase GC, the absolute configurations of the lactones in the Egaenus secretion was found to be (4S,5R)-1 (90%) and (4S,5S)-1 (10%). Hydroxy-γ-lactones represent a new class of exocrine defense compounds in harvestmen

Chrysomelidial in the Opisthonotal Glands of the Oribatid Mite, Oribotritia berlesei

Gas chromatographic–mass spectrometric analyses of whole body extracts of Oribotritia berlesei, a large-sized soil-dwelling oribatid mite, revealed a consistent chemical pattern of ten components, probably originating from the well-developed opisthonotal glands. The three major components of the extract were the iridoid monoterpene, (3S,8S)-chrysomelidial (about 45% of the extract), the unsaturated hydrocarbon 6,9-heptadecadiene, and the diterpene β-springene (the latter two, each about 20–25% of the extract). The remaining minor components (together about 10% of the extract) included a series of hydrocarbons (tridecene, tridecane, pentadecene, pentadecane, 8-heptadecene, and heptadecane) and the tentatively identified 9,17-octadecadienal. In contrast, analysis of juveniles showed only two compounds, namely a 2:1 mixture of (3S,8S)-chrysomelidial and its epimer, epi-chrysomelidial (3S,8R-chrysomelidial). Unexpectedly, neither adult nor juvenile secretions contained the so-called astigmatid compounds, which are considered characteristic of secretions of oribatids above moderately derived Mixonomata. The chrysomelidials, as well as β-springene and octadecadienal, are newly identified compounds in the opisthonotal glands of oribatid mites and have chemotaxonomic potential for this group. This is the first instance of finding chrysomelidials outside the Coleoptera

Naphthoquinones and Anthraquinones from Scent Glands of a Dyspnoid Harvestman, Paranemastoma quadripunctatum

Extracts of Paranemastoma quadripunctatum (Opiliones, Dyspnoi, Nemastomatidae) contained seven components, all of which likely originated from the secretion of well-developed prosomal scent glands. The two main components (together accounting for more than 90% of the secretion) were identified as 1,4-naphthoquinone and 6-methyl-1,4-naphthoquinone. The minor components were 1,4-naphthalenediol, two methoxy-naphthoquinones (2-methoxy-1,4-naphthoquinone, and 2-methoxy-6-methyl-1,4-naphthoquinone) and two anthraquinones (2-methyl-9,10-anthraquinone and a dimethyl-9,10-anthraquinone). While some chemical data on scent gland secretions of the other suborders of Opiliones (Cyphophthalmi, palpatorean Eupnoi, and Laniatores) already exist, this is the first report on the scent gland chemistry in the Dyspnoi. Naphthoquinones are known scent gland exudates of Cyphophthalmi and certain Eupnoi, methoxy-naphthoquinones and anthraquinones are new for opilionid scent gland secretions

Life as a fortress – structure, function, and adaptive values of morphological and chemical defense in the oribatid mite Euphthiracarus reticulatus (Actinotrichida)

Background: Oribatid mites are among the primordial decomposer faunal elements and potential prey organisms insoil. Among their myriad morphological defenses are strong sclerotization and mineralization, cuticular tecta, and the “ptychoid” body-form, which allows to attain an encapsulated, seed-like appearance. Most oribatid mites possess a pair of exocrine glands that produce blends of hydrocarbons, terpenes, aromatics, alkaloids and cyanogenic compounds.Many species evolved “holistic” defensive strategies by combining several morphological and chemical traits. Methods: We describe the morphological and chemical bases of defense in the ptychoid oribatid Euphthiracarus reticulatus. The functional morphology was investigated with synchrotron X-ray microtomography (SRμCT) and highspeed life-radiography. Gland secretions were collected from 20,000 adult specimens, purified and fractionated by preparative capillary gas chromatography (pcGC) and analyzed by gas chromatography / mass spectrometry (GC/MS), high-resolution mass spectrometry (HRMS), and nuclear magnetic resonance spectroscopy (NMR). The adaptive values of morphological and chemical defenses were estimated in bioassays against three predators: a similar-sized gamasid mite (Stratiolaelaps miles, ca. 0.8 mm, with slender chelicera for piercing membranous cuticular regions), and two larger staphylinid beetles, Stenus juno (ca. 7 mm, bearing a harpoon-like sticky labium and sickle-shaped mandibles) and Othius punctulatus (ca. 14 mm, bearing plesiomorphic chewing mandibles). Results: The secretions comprised two components: the diterpene β-springene and a novel compound with a mass of 276 g/mol – eventually elucidated as 2-(but-1-en-1-yl)-4-butylidene-3-(pent-2-en-1-yl)-pentanedial, to which we assign the trivial name δ-acaridial. Upon attacks by S. juno, E. reticulatus reacted quickly: within 150 ms from the first contact the encapsulation was almost completed – less time than the beetle needed to retract the labium and transfer the mite to the mandibles. Chemically-defended specimens of E. reticulatus effectively repelled all predators. After depletion of oil-gland reservoirs, however, O. punctulatus easily fed on the mites while S. miles and S. juno were not able to overcome the morphological barrier of strong cuticle and ptychoid body form. Conclusion: Such an effective, holistic defense strategy, involving both morphological and chemical traits, probably carries high resource-costs, but it allows adult euphthiracaroid mites to occupy an almost “enemy-free space” despite the high diversity of predators in soil