Description of the Males of Androlaelaps misionalis and Androlaelaps ulysespardinasi (Acari: Parasitiformes: Laelapidae) Parasitic of Sigmondontine Rodents From Northeastern Argentina.

Laelapinae mites are common ectoparasites of small mammals, mainly sigmodontine rodents, but males are not frequent in natural populations. In this study, the morphology of the unknown males of Androlaelaps misionalis Lareschi, 2010 and Androlaelaps ulysespardinasi Lareschi, 2011 are described. The males of these species differ from the male of Androlaelaps rotundus (da Fonseca, 1936), a close species, because of the size and shape of their dorsal shield and the length of paranal and sternal st1 and st2 setae. The males of A. misionalis and A. ulysespardinasi differ in their size, in the distance of j6 setae in the dorsal shield, length of hypostomal seta hyp3, number of accessory setae in holoventral shield, length of postanal and sternal st3 setae, number of opisthogastric setae in unarmed integument lateral to level of coxae IV, and shape of tip of movable digit in the chelicera.

Pathological Changes Associated with Eggs and Larvae of Unionicola sp. (Acari: Unionicolidae) Infecting Strophitus connasaugaensis (Bivalvia: Unionidae) from Alabama Creeks.

We detail gross and histopathological changes associated with infection by the eggs, larvae, and cuticular remnants of Unionicola sp. in the mantle, gill, and visceral mass of 25 Alabama creekmussels, Strophitus connasaugaensis, collected during May 2010 through July 2012 from 2 Alabama streams. A multitude (estimated mean intensity >100) of mite eggs and larvae typically infected mantle, gill, and visceral mass integument. Pathology associated with eggs (prevalence = 0.57) and larvae (prevalence = 0.39) typically consisted of localized distension of the infection site; a host response to these infections was indeterminate. However, larval mites embedded in suprabranchial connective tissues were typically encapsulated (prevalence = 0.89). Mite remnants (prevalence = 0.5) occurred in mantle, gill, visceral mass integument, foot, heart, pericardial gland, intestinal lamina propria, and were typically encapsulated. We speculate that S. connasaugaensis clears some infections but is recolonized by autoinfection or horizontal dispersal of mites in the stream. Noteworthy is that high-intensity infections seemingly do not markedly impact the histological picture of mussel tissues, indicating that mites are relatively benign symbionts that are of little concern to mussels under normal environmental conditions.

A novel fluid-feeding mechanism for microbivory in the Acariformes (Arachnida: Acari).

Low temperature scanning electron microscopy (LT-SEM) has revealed anatomical details suggesting that Osperalycus and Gordialycus (Acariformes: Nematalycidae) have an unusual feeding apparatus that is hypothesized to be specialized for feeding on the fluid contents of small microorganisms (diameter<5 µm). Both mite genera have a feeding strategy that appears to involve picking up small microorganisms and placing them onto the subcapitulum for puncturing. However, they have slightly different variants of the same basic rupturing mechanism. Whereas Gordialycus has evolved expansive and convergent rutella to hold the microorganisms in place while pushing chelicerae into them, Osperalycus has evolved a pouch into which a microorganism is inserted. The rutella reinforce this pouch while the chelicerae break up the microorganism. Both types of mouthpart apparatus seem to be adapted to minimize waste, an appropriate specialization given the organically impoverished habitats in which these mites live.

Gonads in Histiostoma mites (Acariformes: Astigmata): structure and development.

The development of male and female gonads in arrhenotokous and thelytokous species of Histiostoma was studied using transmission electron microscopy (TEM). All instars were examined: larvae, protonymphs, facultative heteromorphic deutonymphs (=hypopi), tritonymphs, and adults. In testis primordium, spermatogonia surrounding a testicular central cell (TCC) with a gradually enlarging, branched nucleus are present already at the larval stage. Spermatogonia and the TCC are connected via narrow, tubular intercellular bridges revealing that the TCC is a germline cell. Spermatocytes appear at the protonymphal stage. At the heteromorphic deutonymph stage, the testis primordium is similar to that of the protonymph, but in the tritonymph it is much larger and composed as in the adult: spermatids as well as sperm cells are present. The latter are congregated ventrally in the testis at the entrance of the deferent duct. In the larval ovary, an eccentrically located ovarian nutritive cell (ONC) is surrounded by oogonia which are connected with the ONC via tubular intercellular bridges. In later stages, the ovary grows and oocytes appear in the protonymph. Meiotic synaptonemal complexes in oocytes occur from the tritonymph stage. At about the time of the final molting, tubular intercellular bridges transform into peculiar diaphragm-crossed bridges known only in Histiostoma mites. In the adult female, growing oocytes at the end of previtellogenesis lose intercellular bridges and move ventro-laterally to the ovarian periphery towards the oviduct entrance. Vitellogenesis occurs in oviducts. Germinal cells in both the testis and ovary are embedded in a few somatic stroma cells which may be well discernible already in the larval ovary; in the testis, somatic stroma cells are evident not earlier than the end of the tritonymphal stage. The ovary has a thin wall of flat somatic cells, whereas the testis is covered by a basal lamina only. The obtained results suggest that gonads in Histiostoma and other Astigmata originate from two primordial cells only.

A new species of eriophyoid mite, Aceria tripuraensis sp. n. (Acari: Eriophyoidea), on Hibiscus macrophyllus from India.

A new species of Eriophyidae (Acari: Prostigmata: E riophyoidea) mite, Aceria tripuraensis n. sp., is described from the closed bud galls of Hibiscus macrophyllus Roxb. ex Hornem. (Malvaceae) in India. Aceria tripuraensis n. sp. is distinguished by having a prodorsal shield with distinct rounded lobes on the postero-lateral margins and two pairs of submedian lines. The tarsal solenidia with unusual transverse sculptures, are 2.5x longer than the empodia. Twenty Aceria species are now known to inhabit malvaceous plant hosts and those are listed here along with type localities and host plant details. A key to all known species of Aceria recorded from Hibiscus spp. is also provided.

Hidden in the mangrove forest: the cryptic intertidal mite Carinozetes mangrovi sp. nov. (Acari, Oribatida, Selenoribatidae).

The small archipelago of Bermuda is a geologically young landmass in the Western Atlantic Ocean and recently turned out to be inhabited by a number of intertidal oribatid mites. One newly described species, Carinozetes bermudensis, showed an unusual vast range of habitats like sandy beaches, rocky substrate and mangroves. In the present study, 13 Bermudian populations of C. bermudensis were analysed to verify species integrity of specimens from different microhabitats. A morphometric analysis of 17 continuous variables as well as a molecular genetic investigation of the mitochondrial cytochrome oxidase subunit I revealed the existence of a new species Carinozetes mangrovi sp. nov., inhabiting exclusively intertidal algae growing on mangrove roots. Although both species are morphologically nearly identical, the configuration of the genus-specific ventral carinae represents a clear diagnostic character. The high genetic divergence of approximately 12 % of the cytochrome oxidase subunit I gene sequence between C. bermudensis and C. mangrovi sp. nov. suggests that these two species diverged before the emergence of the Bermuda islands. Accordingly, both of them are older than the geologically young archipelago of Bermuda.

Genetic and morphological diversity of Trisetacus species (Eriophyoidea: Phytoptidae) associated with coniferous trees in Poland: phylogeny, barcoding, host and habitat specialization.

Eriophyoid species belonging to the genus Trisetacus are economically important as pests of conifers. A narrow host specialization to conifers and some unique morphological characteristics have made these mites interesting subjects for scientific inquiry. In this study, we assessed morphological and genetic variation of seven Trisetacus species originating from six coniferous hosts in Poland by morphometric analysis and molecular sequencing of the mitochondrial cytochrome oxidase subunit I gene and the nuclear D2 region of 28S rDNA. The results confirmed the monophyly of the genus Trisetacus as well as the monophyly of five of the seven species studied. Both DNA sequences were effective in discriminating between six of the seven species tested. Host-dependent genetic and morphological variation in T. silvestris and T. relocatus, and habitat-dependent genetic and morphological variation in T. juniperinus were detected, suggesting the existence of races or even distinct species within these Trisetacus taxa. This is the first molecular phylogenetic analysis of the Trisetacus species. The findings presented here will stimulate further investigations on the evolutionary relationships of Trisetacus as well as the entire Phytoptidae family.

A review of the ecology and distribution of Protoribates (Oribatida, Oripodoidea, Haplozetidae) in Alberta, Canada, with the description of a new species.

The oribatid mite genus Protoribates Berlese (Haplozetidae) is reviewed for North America and the genus diagnosis is revised to account for the North American species, Protoribates robustior (Jacot, 1937) is redescribed and newly reported from western North America and a new species from Alberta is described. Protoribates haughlandae sp. n. is bisexual, heterotridactylous, and lives primarily in the peat soils of fens and bogs. Protoribates robustior is all-female, monodactylous, and occurs primarily in dry forests or in dry, treeless sites dominated by grasses, sedges, and shrubs. Both species feed on fungal hyphae and spores, but P. haughlandae also is an opportunistic predator and/or necrophage of small arthropods and P. robustior gut contents often include material that resembles plant cell walls. Examination of type specimens confirms that Protoribates prionotus (Woolley, 1968) is a junior synonym of the widespread Protoribates lophotrichus (Berlese, 1904). A key to differentiate Lagenobates from Protoribates and to identify the 7 species of the latter that are known or reported from North America is provided.

Anatomy and ultrastructure of dermal glands in an adult water mite, Teutonia cometes (Koch, 1837) (Acariformes: Hydrachnidia: Teutoniidae).

Organization of dermal glands in adult water mites Teutonia cometes (Koch, 1837) was studied using light-optical, SEM and TEM methods for the first time. These glands are large and occur in a total number of ten pairs at the dorsal, ventral and lateral sides of the body. The slit-like external openings of the glands (glandularia) are provided with a cone-shaped sclerite, and are combined with a single small trichoid seta (hair sensillum), which is always situated slightly apart from the anterior aspect of the gland opening. Each gland is formed by an epithelium encompassing a very large lumen (central cavity) normally filled with secretion that stains in varying intensity on toluidine blue stained sections. The epithelium is composed of irregularly shaped secretory cells with an electron-dense cytoplasm and infolded basal portions. The cells possess a large irregularly shaped nucleus and are filled with tightly packed slightly dilated cisterns and vesicles of rough endoplasmic reticulum (RER) with electron lucent contents. Dense vesicles are also present in the apical cell zone. Some cells undergo dissolution, occupy an upper position within the epithelium and have a lighter cytoplasm with disorganized RER. Muscle fibers are regularly present in the deep folds of the basal cell portions and may serve to squeeze the gland and eject the secretion into the external milieu. The structure of these dermal glands is compared with the previously described idiosomal glands of the same species and a tentative correlation with the glandularia system of water mites is given. Possible functions of the dermal glands of T. cometes are discussed.

Hypopi of Hypodectes propus (Acari: Hypoderatidae) in two southern crowned pigeons (Goura scheepmakeri).

Necropsy of 2 4-year-old southern crowned pigeons (Goura scheepmakeri) that died from a presumed case of botulism revealed hundreds of small, cyst-like structures in the pectoral subcutaneous tissues. The structures were identified as heteromorphic deutonymphs of Hypodectes propus (Order Astigmata) of the family Hypoderatidae. The immobile, immature hypopi were individually encapsulated, mostly in adipose tissue, and evoked only a mild inflammatory infiltration of predominately macrophages with some heterophilic granulocytes. The infection was not considered a serious health problem and was interpreted as an incidental finding. To our knowledge, this is a new host record for H. propus.

The delineation of the fourth walking leg segment is temporally linked to posterior segmentation in the mite Archegozetes longisetosus (Acari: Oribatida, Trhypochthoniidae).

Acari (mites and ticks) lack external segmentation, with the only indication of segmentation being the appendages of the prosoma (chelicerae, pedipalps, and four pairs of walking legs). Acari also have a mode of development in which the formation of the fourth walking leg is suppressed until the nymphal stages, following a hexapodal larva. To determine the number of segments in the posterior body region (opisthosoma) of mites, and to also determine when the fourth walking leg segment is delineated during embryogenesis, we followed the development of segmentation in the oribatid mite Archegozetes longisetosus using time-lapse and scanning electron microscopy, as well as in situ hybridizations of the A. longisetosus orthologues of the segmentation genes engrailed and hedgehog. Our data show that A. longisetosus patterns only two opisthosomal segments, indicating a large degree of segmental fusion or loss. Also, we show that the formation of the fourth walking leg segment is temporally tied to opisthosomal segmentation, the first such observation in any arachnid.

Plant-feeding and non-plant feeding phytoseiids: differences in behavior and cheliceral morphology.

In previous studies plant feeding behavior of plant- and non-plant feeding phytoseiids was never examined directly. Moreover, in these studies the cheliceral morphology of phytoseiids was not associated with their ability to feed on plants. In the present study, we monitored the plant-feeding behavior of Euseius scutalis and Amblyseius swirskii. Only E. scutalis was observed penetrating the leaf surface with the movable digit and feeding. Second, using a dye and coloring the gut as an indicator for feeding, we found that E. scutalis pierced an artificial membrane and fed whereas A. swirskii did not. Finally, to identify morphological characteristics typical of plant feeders versus non-plant feeders, we used scanning electron microscopy to examine the adaxial (inner) profile of the chelicerae in 13 phytoseiid species. The only parameter that distinguished between plant- and non-plant feeders was the ratio of the dorsal perimeter length of the fixed digit to the ventral perimeter length of the movable digit. Plant-feeders were characterized by ratio values greater than one whereas the values for non plant-feeders were lower than one. We suggest that a shorter and less curved movable digit, expressed by a high ratio, will facilitate the penetration of the leaf surface. Cheliceral traits proposed here as typical of plant feeders, were observed for five genera, indicating that plant-feeding may be more common in the Phytoseiidae than previously reported. We propose that the ability to feed on plants be added as a cross type trait of phytoseiid life-style types.

The oviduct is a brood chamber for facultative egg retention in the parthenogenetic oribatid mite Archegozetes longisetosus AOKI (Acari, Oribatida).

Archegozetes longisetosus is a parthenogenetic oribatid mite and a chelicerate model organism. We examined the localisation of processes between vitellogenesis and embryogenesis as well as the anatomy and histology of involved structures by means of light- and electron microscopy. The proximal oviduct is differentiated into an oviductal bulb, exhibiting a strong secretory epithelium. Here, solidification of the egg shell instantaneously occurs upon passing of the egg from the perivitelline space into the oviductal lumen. This is interpreted as an internalised oviposition with the generation boundary being effectively located at the ovary-oviduct transition, rendering the oviducts into functional brood chambers. The parity mode combines elements of oviparity and ovolarviparity with facultative egg retention.

A gallery of the key characters to ease identification of Dermanyssus gallinae (Acari: Gamasida: Dermanyssidae) and allow differentiation from Ornithonyssus sylviarum (Acari: Gamasida: Macronyssidae).

BACKGROUND: Dermanyssus gallinae (poultry red mite) is a major threat for the poultry industry and is of significant interest for public health. Identification of D. gallinae can be difficult for scientists not familiar with mite morphology and terminology especially when trying to use identification keys. Moreover, this species may easily be confused with another dermanyssoid mite, Ornithonyssus sylviarum (northern fowl mite), which often shares the same hosts and environment. METHODS: Specimens of D. gallinae were collected at poultry farms in the Puglia and performed for light and scanning electron microscopy observations, identification and micrographs. Moreover specimens of O. sylviarum were collected separately macerated and mounted on slides for light microscopy observations, identification and pictures. RESULTS: The micrographs used in this study, based on LM and SEM observations, highlight the following important identifying characters of D. gallinae: the prominent shoulders of the dorsal shield and the jagged edges of the shield reticulations, the position of setae j1, s1 and the epigynal pores, and the presence on tibia IV pl of one seta. Additional micrographs highlighting the shape of the dorsal (abruptly narrowed posteriorly) and epigynal (narrowly rounded posteriorly) shields and the chelicera (elongate, with distinct digits) of O. sylviarum enable its differentiation from D.gallinae. CONCLUSION: The photographic support provided here (both LM and SEM pictures) can be considered a practical tool for scientists who are not well acquainted with the morphology of D.gallinae, and who are involved with classical and molecular systematics, veterinary and human health aspects of poultry red mites.

Mid-Cretaceous charred fossil flowers reveal direct observation of arthropod feeding strategies.

Although plant-arthropod relationships underpin the dramatic rise in diversity and ecological dominance of flowering plants and their associated arthropods, direct observations of such interactions in the fossil record are rare, as these ephemeral moments are difficult to preserve. Three-dimensionally preserved charred remains of Chloranthistemon flowers from the Late Albian to Early Cenomanian of Germany preserve scales of mosquitoes and an oribatid mite with mouthparts inserted into the pollen sac. Mosquitoes, which today are frequent nectar feeders, and the mite were feeding on pollen at the time wildfire consumed the flowers. These findings document directly arthropod feeding strategies and their role in decomposition.

Comparative morphology and ultrastructure of the mouthparts in unfed larvae of Platytrombidium fasciatum and Camerotrombidium pexatum (Acariformes: Microtrombidiidae).

The mouthparts of unfed larvae of Platytrombidium fasciatum (C. L. Koch, 1836) and Camerotrombidium pexatum (C. L. Koch, 1837) (Acariformes: Microtrombidiidae) were studied using both light optical (whole-mounted specimens, toluidine blue stained semi-thin sections) and electron microscope (TEM, SEM) methods. The mouth apparatus incorporated within the gnathosoma occupies an axial position and is covered from above by the arched dorsal shield, or scutum. The chelicerae are comparatively long and separated, and the lateral lips form a permanent apomorphic sucker provided with an internal cuticular sclerite. The pharynx is extremely wide and totally fused with the bottom of the infracapitulum. The pharyngeal dilators originate on the posterior portions of the cervix (epistome) and on the capitular apodemes and run nearly parallel to the cervix to the dorsal pharyngeal wall. Comparatively short sigmoid pieces serve as origin of the muscles--cheliceral levators inserting on the posterior wall of the basal cheliceral segments. There are two sets of the extrinsic gnathosomal muscles originating on the posterior portion of the scutum: retractors of chelicerae inserting on the posterior portions of the basal cheliceral segments, and retractors of the gnathosoma inserting on the very posterior parts of the capitular apodemes. The labrum and the cervix delimit the pharynx and the subcheliceral space. The labrum and the cervix for the most part are weakly sclerotized cuticular plates and do not have own muscles. The larval mouth apparatus, in comparison with that of adult microtrombidiid mites, is simply organized and more specialized for ingestion of large masses of liquid food.

Light and scanning electron microscopic investigations on MiteStop-treated poultry red mites.

Recent studies of the neem seed product MiteStop showed that it has a good acaricidal effect against all developmental stages of the poultry red mite, Dermanyssus gallinae. In vitro tests proved an efficacy at direct contact, as well as by fumigant toxicity. Light and scanning electron microscopic (SEM) investigations showed no clear, morphologically visible signs of an effect caused by fumigant toxicity. Direct contact with the neem product, however, seemed to be of great impact. Chicken mites turned dark brown or even black after being treated with the neem product. SEM analysis showed damages along the body surface of the mites.

Detection of European mountain ash ringspot-associated virus-specific RNA and protein P3 in the pear leaf blister mite Phytoptus pyri (Eriophyidae).

The means by which European mountain ash ringspot-associated virus (EMARaV), a minus-strand ssRNA virus and the type member of the genus Emaravirus, is naturally spread, is unknown. In attempts to identify an EMARaV vector, galls induced by the eriophyid mite Phytoptus pyri were frequently found on infected leaves. By immunofluorescence microscopy, the presence of EMARaV nucleocapsid protein P3 was demonstrated in P. pyri individuals collected from diseased plants. Furthermore, RT-PCR analysis of entire P. pyri individuals revealed the presence of both viral genomic ss(-)RNAs and antigenomic ss(+)RNAs, suggesting that P. pyri might be a candidate vector of EMARaV.

On the ultrastructure and functional morphology of the male chelicerae (gonopods) in Parasitina and Dermanyssina mites (Acari: Gamasida).

Males of Parasitina and Dermanyssina (Gamasida=Mesostigmata) have chelicerae modified to function as gonopods. The slit-like spermatotreme in the movable digit of the chela in males of Parasitina was studied in three species: in Pergamasus quisquiliarum and Holoparasitus sp. a rather simple slit is indeed present, whereas in Vulgarogamasus kraepelini the structure is represented by a fine duct traversing the movable digit. The spermatodactyl studied in two phytoseioid species (Phytoseiulus persimilis, Blattisocius dentriticus) of Dermanyssina is a slender process arising from the movable digit and containing a fine duct which is formed by cuticular folds. The spermatodactyl of these species thus differs remarkably from that described in Veigaia sp. The diversity of these structures seen in the few taxa studied up to now is discussed under functional and systematic aspects.

The ultrastructural investigation of the midgut in the quill mite Syringophilopsis fringilla (Acari, Trombidiformes: Syringophilidae).

The midgut of the females of Syringophilopsis fringilla (Fritsch) composed of anterior midgut and excretory organ (=posterior midgut) was investigated by means of light and transmission electron microscopy. The anterior midgut includes the ventriculus and two pairs of midgut caeca. These organs are lined by a similar epithelium except for the region adjacent to the coxal glands. Four cell subtypes were distinguished in the epithelium of the anterior midgut. All of them evidently represent physiological states of a single cell type. The digestive cells are most abundant. These cells are rich in rough endoplasmic reticulum and participate both in secretion and intracellular digestion. They form macropinocytotic vesicles in the apical region and a lot of secondary lysosomes in the central cytoplasm. After accumulating various residual bodies and spherites, the digestive cells transform into the excretory cells. The latter can be either extruded into the gut lumen or bud off their apical region and enter a new digestive cycle. The secretory cells were not found in all specimens examined. They are characterized by the presence of dense membrane-bounded granules, 2-4 microm in diameter, as well as by an extensive rough endoplasmic reticulum and Golgi bodies. The ventricular wall adjacent to the coxal glands demonstrates features of transporting epithelia. The cells are characterized by irregularly branched apical processes and a high concentration of mitochondria. The main function of the excretory organ (posterior midgut) is the elimination of nitrogenous waste. Formation of guanine-containing granules in the cytoplasm of the epithelial cells was shown to be associated with Golgi activity. The excretory granules are released into the gut lumen by means of eccrine or apocrine secretion. Evacuation of the fecal masses occurs periodically. Mitotic figures have been observed occasionally in the epithelial cells of the anterior midgut.