How can Dermanyssus gallinae (De Geer 1778) (Acari: Anactinotrichida: Dermanyssidae) walk upwards on slippery surfaces?

ABSTRACTScanning electron microscopy observations of the distal leg region of the poultry red mite Dermanyssus gallinae (De Geer 1778) identified the presence of a compound ambulacrum, the part of ..

Morfologia funzionale delle parti boccali di Penthaleus major (Dugés) (Eupodoidea: Penthaleidae)

FUNCTIONAL MORPHOLOGY OF PENTHALEUS MAJOR (DUGÈS) MOUTHPARTS (EUPODOIDEA: PENTHALEIDAE) The functional morphology of Penthaleus major (Dugés) mouthparts has been studied by means of light microscope, scanning and trasmission electron microscopes. The movable digit with its basal sclerite, cheliceral, pharyngeal and infracapitular muscles are described and illustrated. The chelicerae present protractors and retractors muscles of the stylets and depressors muscles of the II cheliceral article. The muscles of the pharynx are represented by dorsal dilatators. The lateral lips show two slips of muscles. A hypothesis about the feeding mechanism has been expressed and a comparison with other groups of mites has been made. Key words: Prostigmata, gnathosoma, musculature, basal sclerite, feeding mechanism.È stato condotto uno studio sulla muscolatura delle parti boccali di un acaro Penthaleidae, il Penthaleus major (Dugés), utilizzando il microscopio luce, quello elettronico a scansione e a trasmissione. Sono stati osservati e descritti il digitus mobilis ed il relativo sclerite basale, i muscoli dei cheliceri, quelli della pompa faringeale e delle labbra laterali. La muscolatura dei cheliceri risulta costituita dai muscoli protrattori e retrattori degli stiletti e da tre muscoli dorso-ventrali depressori del secondo articolo chelicerale. Per la pompa faringeale è stato individuato un gruppo di muscoli dilatatori dorsali mentre per le labbra laterali sono stati descritti due muscoli adduttori delle stesse. Infine è stata formulata un’ipotesi circa il comportamento trofico dell’acaro ed una successiva comparazione con le strutture descritte per altri gruppi di acari. Parole chiave: Prostigmata, gnatosoma, muscolatura, sclerite basale, meccanismo trofico.

Mouthparts of a tydeid mite: an ultrastructural and functional investigation

The gnathosoma of a tydeid mite (Tydeus sp.) shows the subcapitulum and the cheliceral segments not fused to each other though closely appressed. The lateral lips are provided with a well defined system of grooves and rims for interlocking. The pre-oral groove has very electron- dense walls; it is tightly shaped and covered dorsally by the labrum only distally. More proximally it becomes a channel (food channel), dorsally sealed. The labrum is an unpaired structure involved in keeping the cheliceral stylets into the cheliceral groove and in covering the pre-oral groove distally. The fixed digits and the basal segments of the chelicerae are shaped to adhere to the lateral lips and mesally to each other; they are not fused to form a stylophore. The movable digits are stylet-like, reach the tip of the gnathosoma and are proximally articulated with a large lever provided with two strong knobby apodemes. A pharyngeal pump connected to the food channel activates and controls the intake of the alimentary fluids. Some sensorial structures associated with the mouthparts components have been observed and described. Key words: stylets, gnathosoma, lever, fixed digits, labrum, functional morphology. STUDIO ULTRASTRUTTURALE E FUNZIONALE DELLE PARTI BOCCALI DI UN ACARO APPARTENENTE ALLA FAMIGLIA TYDEIDAE È stato realizzato uno studio morfologico e funzionale delle parti boccali in un acaro Tideide. Il subcapitulum ed i segmenti chelicerali, pur essendo morfologicamente strutturati per aderire gli uni agli altri, non si presentano fusi a costituire una capsula gnatosomatica; le labbra laterali presentano, lungo la loro superficie adorale, un sistema di solchi e creste che consente loro di coaptarsi. Il solco perorale si presenta coperto dal labrum solo distalmente; più prossimamente diventa invece un vero canale delimitato dorsalmente da pareti. Pertanto il labrum sembra coinvolto principalmente nella funzione di mantenere in posizione gli stiletti e coprire il solco perorale solo nel tratto distale. La morfologia esterna dei digiti fissi e dei segmenti basali dei cheliceri consente loro di aderire alle labbra laterali e l’un all’altro nella regione adorale; non si ha la presenza di uno stiloforo. I digiti mobili sono stilettiformi, ciascuno di loro si articola prossimamente ad un lever la cui rotazione consente la protrusione e retrazione degli stiletti stessi con perforazione dei tessuti o del substrato alimentare. La pompa faringeale, collegata al canale alimentare, consente l’aspirazione dell’alimento. Infine alcune strutture sensoriali connesse alle parti boccali sono state osservate e descritte. Parole chiave: stiletti, gnatosoma, digito fisso, lever, labrum, morfologia funzionale

First record of Tarsonemus caucasicus (Acari, Tarsonemidae) in Italy, with notes on morphology and systematics

Tarsonemus caucasicus Sharonov Mitrofanov (Acari: Tarsonemidae) is re-described and illustrated, on the base of newly recorded material from Apulia (Italy), where it was found affecting laboratory cultures of fungi. The morphology and systematic position of the species are briefly discussed. Key words: morphology, systematics, taxonomy, T. bilobatus, lab fungi cultures. T. caucasicus (Acari: Tarsonemidae) viene ridescritto sulla base di un nuovo ritrovamento in Puglia (Italia) su colture di laboratorio di Verticillum dahliae e Armillaria mellea. Segue una discussione sulla morfologia e posizione sistematica di questa specie. Parole chiave: morfologia, sistematica, tassonomia, T. bilobatus, funghi in colture di laboratorio

Fine structure and functional morphology of the mouthparts of a male Veigaia sp (Gamasida: Veigaiidae) with remarks on the spermatodactyl and related sensory structures

Mites of the genus Veigaia are common gamasid inhabitants of forest litter. They engage in the peculiar reproductive strategy of podospermy which, along with other morphological and behavioral adaptations, involves modification of the chelicerae of the relatively rare males into gonopods. Each movable digit is provided with an appendage (spermatodactyl) that is involved in sperm transfer. We describe the gross anatomy, fine structure, and functional morphology of the mouthparts of a male Veigaia species and give ultrastructural details for the corniculi, laciniae, preoral cavity, labrum, pharynx, and movable and fixed digits. The fine structure of the spermatodactyl is illustrated here for the first time in detail. A semischematic reconstruction of the gnathosoma and spermatodactyl is provided. The spermatodactyl is totally fused with the movable digit and a sperm transfer duct runs along its entire length. This duct starts at the adaxial base of the movable digit, continues inside the digit into the tube of the spermatodactyl, and finally opens at the distal abaxial surface of the spermatodactyl. Several sensory structures associated with the spermatodactyl probably provide the male with mechanical and chemical clues

Ununguitarsonemus rarus (Acari: Tarsonemidae), a new species of mite associated with bark beetle from Crimea, Ukraine

Ununguitarsonemus rarus (Acari: Tarsonemidae), a new mite species phoretic on Dryocoetes villosus (Fabr.) (Coleoptera: Scolytidae) from Crimea, Ukraine is described and illustrated. Another species, U. peacocki Smiley et Moser, 1974, is briefly redescribed. Systematic position of the new taxon is briefly discussed and diagnosis of the genus Ununguitarsonemus is emended. Key words: Heterostigmata, systematic, taxonomy, morphology. UNUNGUITARSONEMUS RARUS (ACARI: TARSONEMIDAE) N. SP. FORETICA SU DRYOCOETES VILLOSUS (COLEOPTERA: SCOLYTIDAE) RINVENUTA IN CRIMEA, UCRAINA Ununguitarsonemus rarus (Acari: Tarsonemidae) specie nuova associata a Coleotteri Scolitidi, rinvenuta in Crimea, Ucraina, viene descritta e illustrata. Si tratta della terza specie del genere e della prima segnalazione europea del genere stesso. Inoltre U. peacocki Smiley et Moser, 1974 viene brevemente ridescritta. Infine la posizione sistematica della nuova specie e la diagnostica del genere Ununguitarsonemus viene discussa. Parole chiave: Heterostigmata, sistematica, tassonomia, morfologia

Morphological adaptations of mite chelicerae to different trophic activities (Acari)

The authors briefly review the current knowledge on the structural organization and functional significance of the chelicerae and their sensory structures among mites of economical interest in agriculture that have been recently investigated for their gnathosoma. The chelicerae of the polyphagous predatory mite Typhlodromus exhilaratus Ragusa (Gamasida, Phytoseiidae) have a rather unspecialized organization and are of chelate type. They function mainly in grasping the prey and other food, while the other mouthparts are adapted to prey wounding, salivary injection and juice suction. In the Honey Bee parasite, Varroa destructor Anderson Trueman (Gamasida, Varroidae), the chelicerae have almost completely lost the fixed digit while the movable digit is thinner and elongated. The chelicerae participate directly, along with the other mouthparts, only in the perforation of the Honey Bee integument. In the plant-feeder, Penthaleus major (Dugès) (Actinedida, Penthaleidae), the movable digit is composed of a long and stout stylet-like structure, and a peculiar basal sclerite which activates the digit movements. During cheliceral protrusion, the stylets may work jointly or independently from each other in piercing the plant surface and causing deep and large wounds. The protruded stylets may justapose each other; they may delimit an intercheliceral channel and may be involved in salivary injection. The fixed digit is a large somewhat soft structure which covers dorsally the pre-oral and supralabral chamber, and is passively involved in juice sieving and sucking. The movable digit of the fungivorous Tarsonemus nodosus Schaarschmidt (Actinedida, Tarsonemidae) is needle-like and articulated with a transverse lever to the second cheliceral article. The basal cheliceral articles are fused together forming a stylophore. The fixed digits partly envelop the movable digits and they are consolidated with the subcapitulum. The stylar morphology suggests an independent piercing action of the movable digits. The phytophagous Two-Spotted Spider mite, Tetranychus urticae Koch (Actinedida, Tetranychidae), and False Red Spider mite, Cenopalpus pulcher (Canestrini Fanzago) (Actinedida, Tenuipalpidae), have extensively protractable styliform chelicerae. The movable digits are very elongated and stylet-like, originating proximally from the stylophore (fused first cheliceral articles); the fixed digits are partially fused to each other. During cheliceral protrusion, the stylets are forced to be interlocked to each other to delimit an intercheliceral canal which is directly connected to the salivary duct. At the same time, the fused fixed digits are involved in salivary pump functioning. So, the chelicerae play a double role in piercing the plant surface and discharging saliva into the host tissue. In the tiny phytophagous mites of the superfamily Eriophyoidea (Actinedida), the gnathosoma has a strongly derived organization. Fixed and movable digits are both styliform, laminar shaped, and included in a strict frame of nine stylets of different origin which function together in host piercing, salivary injection and juice suction. The short sliding movements of the cheliceral shafts are activated by the unpaired motivator. The chelicerae seem to be mainly involved in deeping the mouthparts into the wounds and partially in salivary injection. In each of the investigated species, chelicerae are provided with putative chemoreceptive sensilla, in addition to other mechanoreceptors, which seem to be strictly involved in food perception and acceptance. As yet, however, an alternative perceptive function cannot be excluded. Key words: Acari, gnathosoma, mouthparts, feeding mechanisms, sensory structures, digitus mobilis, digitus fixus, morphological adaptations, host piercing, salivary injection, basal sclerite, lever, motivator, stylophore

Use of a reactive transport model to describe reductive dechlorination (RD) as a remediation design tool: application at a CAH-contaminated site

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Wound Myiasis Caused by Sarcophaga (Liopygia) Argyrostoma

In Mediterranean countries, Sarcophaga (Liopygia) crassipalpis, Sarcophaga (L.) argyrostoma, and Sarcophaga (L.) cultellata share the same ecological niche and can be responsible of myiasis. In this study, the main morphological characters of a larva found in a hospitalized woman were described and illustrated by light and SEM microscopy and the features discussed. Then, a fragment within the mitochondrial encoded cytochrome c oxidase subunit I (coxI) gene of ~735 bp was amplified and sequenced. The molecular investigation was necessary to confirm the species Sarcophaga (Liopygia) argyrostoma (99% of identity). Our findings showed that morphological descriptions of larvae of three Mediterranean species of Liopygia available in several papers might not be clear enough to allow for comparison and correct identification. Until results of reliable comparative studies of larvae of all three species will be available, the use of molecular tools is crucial, to avoid misleading or incomplete identification, and in particular when a myiasis becomes a legal issue