Oribatid mites (Acari) from nests of some birds in South Vietnam

The fauna of oribatid mites in nests of the bar-bellied pitta, the blue-rumped pitta, and the whiterumped shama was studied at the Dong Nai Biosphere Reserve (South Vietnam). The data on the taxonomic composition, total number of species, dominant species, and their occurrence in nests are presented.     

Oribatid mites (Acari,Oribatida) from riverine environments of some islands in Oceania

A checklist of identified oribatid mite taxa from riverine freshwater environments from six islands in Polynesia (New Caledonia, Tahiti, Moorea, Rurutu, Tubuai, Raiatea) is presented; 18 species, 16 genera and eight families were recorded. Trhypochthoniellus longisetus (Berlese, 1904) and Trimalaconothrus albulus Hammer, 1972 prevailed on distribution. Fortuynia smiti sp. n. (Fortuyniidae) is described from New Caledonia. The new speciesis morphologically most similar to Fortuynia marina Hammen, 1960 from New Guinea, but it differs from the latter by the longer notogastral setae dm, lm, c₂, p₁, epimeral setae 3b and adanal setae ad₁ and the presence of prodorsal lateral ridges.     

Ecdysial cleavage lines of acariform mites (Arachnida, Acari)

Among mites the ancestral ecdysial cleavage line, or line of dehiscence (a), is inferred by outgroup comparison to be prodehiscent: U-shaped, passing around the front of the mite just above the insertions of the appendages, such that the mite ecloses anteriorly. From preserved and living individuals and exuviae, we found prodehiscence (or its slight variations) to be widespread in Acariformes. It appears to be pervasive in endeostigmatic mites, eupodine Prostigmata, and basal taxa in the Oribatida (Enarthronota, Palaeosomata); it is dominant in cleutherengone Prostigmata and is present in at least one anystine family (Caeculidae). Three general modes of dehiscence are considered to be derived within acariform mites. (1) Merodehiscence is a transverse splitting of the dorsal cuticle at or near the juncture of proterosoma and hysterosoma; it evolved separately in thrcc groups of Prostigmata (Tetranychidae, an undefined subgroup within Cheylctidae, and active instars of Parasitengona) and in a genus of Astigmata (Histiogaster). (2) Trarnsdehiscence is a transverse splitting of the dorsal hysterosomal cuticle anterior to the opisthosomal glands; it occurs in middle-derivative oribatid mites (the paraphyletic Desmonomata), and new observations show it to be widespread in Astigmata, lending support to the hypothesis that the latter group evolved from within Desmonomata. (3) Circumdehiscence is a circumferential splitting of the hysterosomal cuticle that may be incomplete anteriorly; it has long been known to characterize the monophyletic oribatid taxon Brachypylina, but it is convergent with a similar dehiscence in an unrelated family, Lohmanniidae. Transdehiscent and circumdehiscent mites eclose posteriorly. Astigmata exhibit the greatest variety of modes of dehiscence, including the three derived modes and a probable reversal to prodehiscence in Algophagidae. Furthermore, heteromorphic deutonymphs (hypopi) may ecdyse differently from other immature instars of the same species.     

Global diversity of water mites (Acari,Hydrachnidia; Arachnida) in freshwater

The Hydrachnidia (water mites) represent the most important group of the Arachnida in fresh water. Over 6,000 species have been described worldwide, representing 57 families, 81 subfamilies and more than 400 genera. The article analyzes extant water mite diversity and biogeography. Data on distribution and species richness of water mites are substantial but still far from complete. Many parts of the world are poorly investigated, Oriental and Afrotropical regions in particular. Moreover, information among different freshwater habitats is unbalanced with springs and interstitial waters disproportionately unrepresented. Therefore, more than 10,000 species could be reasonably expected to occur in inland waters worldwide. Based on available information, the Palaearctic region represents one of the better investigated areas with the highest number of species recorded (1,642 species). More than 1,000 species have been recorded in each of the Neotropical (1,305 species) and Nearctic regions (1,025 species). Known species richness is lower in Afrotropical (787 species) and Australasian (694 species) regions, and lowest in the Oriental region (554 species). The total number of genera is not correlated with species richness and is distinctly higher in the Neotropical (164 genera); genus richness is similar in the Palaearctic, Nearctic and Australasian regions (128–131 genera) and is lower in the Afrotropical and Oriental regions with 110 and 94 genera, respectively. A mean number of about three genera per family occur in the Palaeartic, Nearctic and Oriental while an average of more than four genera characterizes the families of Australasian and Afrotropical regions and more than five genera those of the Neotropical. Australasian fauna is also characterized by the highest percentage of endemic genera (62%), followed by Neotropical (50.6%) and Afrotropical (47.2%) regions. Lower values are recorded for the Palaearctic (26.9%), Oriental (24.4%) and Nearctic (21.4%). The Palaearctic and Nearctic have the highest faunistic similarity, some minor affinities are also evident for the generic diversification of Holarctic and Oriental families. The faunas of Southern Hemisphere bioregions are more distinct and characterized by the presence of ancient Gondwanan clades with a regional diversification particularly evident in the Neotropics and Australasia. This scenario of water mite diversity and distribution reflect the basic vicariance pattern, isolation, phylogenetic diversification, recent climatic vicissitudes and episodes of dispersal between adjacent land masses together with extant ecological factors can be evoked to explain distribution patterns at a global scale. Guest editors: E. V. Balian, C. Lévêque, H. Segers & K. Martens Freshwater Animal Diversity Assessment     

Oribatid mites of the superfamily Trizetoidea Ewing, 1917 (Acari,Oribatida) from Peru

Two new species of the oribatid mite superfamily Trizetoidea (Acari, Oribatida) are described from Peru. Rhynchoribates (Rhynchoribatodes) rioyuyapichisensis Ermilov, sp. n. differs from the other species of the subgenus by the long flagelliform notogastral setae. Rhynchoppia puertoincaensis Ermilov, sp. n. is morphologically similar to R. capillata (Balogh, 1963), but differs by the shape and in a greater number of rostral teeth, in the number and a smaller length of notogastral setae, and in the number of genital setae. The genus Rhynchoppia (Balogh 1968) is recorded from the Neotropical Region for the first time, while Rhynchoribates (Rhynchoribatodes) brasiliensis Woas 1986 is new to the fauna of Peru.     

Fine structure of scorpion trichobothria (Arachnida,Scorpiones)

Summary The fine structure of trichobothria in the scorpions Buthus occitanus (Amoureux, 1789) and Euscorpius carpathicus (Linné, 1767) was investigated by electron microscopy. In both species, cuticular and cellular characteristics are very similar. The articulation of the hair corresponds to that of other arachnid hair sensilla. The receptor endings are excentrically attached to the hair base. They consist of an enveloped S-shaped bundle of seven dendrites in B. occitanus and four in E. carpathicus. Neighbouring outer dendritic segments differ a great deal in diameter and ciliary modification. In B. occitanus, three enveloping cells and several additional secretory cells surround the inner dendritic segments. Structural characteristics are compared to those of other arachnid sensilla and their possible functional significance is discussed.     

Oribatid mites (Acari,Oribatei) of three fens in the northern part of European Russia

Oribatids from three oxbow fens in Kostroma, Kirov, and Arkhangelsk provinces were studied. A total of 2800 adult mites belonging to 74 species were collected. The similarity of the faunas and communities in these fens is rather low, the Jaccard and Naumov coefficients constituting 22–37% and 11–22%, respectively. From the central part of each fen to its periphery, the diversity of oribatids increased from 4–6 to 25–28 species, and abundance, from 59–123 to 451-737 ind./l. Some oribatid species demonstrated similar preferences within all the fens studied. The oribatid faunas of fens and raised bogs are compared, and their characteristic species are distinguished.     

Global diversity of halacarid mites (Halacaridae: Acari: Arachnida) in freshwater

Halacarid mites have successfully invaded the sea and approximately 56 species colonized the freshwater. Invasion from the sea into continental waters probably started in the Mesozoic or Pre-Mesozoic and went on in the following epochs. The number of genera (14) and species (34) recorded from the Palaearctic is remarkably higher than that of other geographical regions. These numbers do not imply that the Palaearctic is a centre of origin, they reflect the sampling activity rather than reliable data on diversity. Guest editors: E. V. Balian, C. Lévêque, H. Segers & K. Martens Freshwater Animal Diversity Assessment     

Vectorial role of some dermanyssoid mites (Acari, Mesostigmata, Dermanyssoidea)

Among transmissible diseases, vectorial diseases represent a major problem for public health. In the group of acarina, while ticks are the most commonly implicated vectors, other arthropods and notably Dermanyssoidea are also involved in the transmission of pathogenic agents. Since the role of this superfamily is at present largely unknown, we have reviewed the vectorial role of these mites in the appearance, survival and propagation of pathogens. Various authors have shown that Dermanyssoidea are implicated in the transmission of both bacteria (Salmonella, Spirocheta, Rickettsia or Pasteurella) and viruses (equine encephalitis viruses, West Nile virus, Fowl pox virus, the virus causing Newcastle disease and tick borne encephalitis viruses or hantaviruses). Finally, some authors have also shown their role in the transmission of some protozoa and filaria. As the vectorial character of such mites has been more clearly demonstrated (Dermanyssus gallinae, Omithonyssus bacoti and Allodermanyssus sanguineus), it would be interesting to continue studies to better understand the role of this superfamily in the epidemiology of certain zoonoses.     

Comparative morphology,functions, and homologies of the coxal glands in oribatid mites (Arachnida: Acari)

1. Forty-eight species of oribatids in 37 families representing most of the superfamilies were collected from various environments (littoral, salt marsh, litter, sod, and freshwater) and sectioned. 2. The coxal gland is composed of a sacculus and a labyrinth in all stages of all oribatid species. Muscles, originating on the body wall, insert at several points on the thin-walled sacculus which opens into the labyrinth. The labyrinth has an internal, chitinous supporting skeleton. The type A labyrinth has 3–180° bends, producing four parallel regions, and occurs in all inferior oribatids. The type B labyrinth has 1–180° bend, producing two parallel regions, and occurs in all superior oribatids. The coxal gland duct and the lateral gland duct join, penetrate the body wall, and empty into the posterior end of the podocephalic canal. All oribatids have lateral accessory glands, but only inferior oribatids have rostral and medial glands. Three ductless coxendral bodies are always present. 3. The labyrinth length in oribatids is correlated with body size and the environment of the species. Oribatids from sod, leaflitter, or moss show a simple correlation of labyrinth length (X) to total body length (Y) where Y = 4.64X. Freshwater species have a labyrinth length greater than that of comparably sized terrestrial species and salt water (littoral) species have a labyrinth length less than that of comparably sized terrestrial species. There is a greater reduction in labyrinth length in species restricted to salt marshes than in species not restricted to salt marshes. 4. The probable function of oribatid coxal glands is osmoregulation. Hemolymph filtration would occur across the sacculus by positive hemolymph pressure and contraction of the sacculus muscles. Resorption of ions would occur in the labyrinth, which is noncollapsible due to the internal skeleton. The hypothesis is that in freshwater species the rate of filtration is high and resorption of ions would have to be very efficient, therefore they have an elongated labyrinth; but in salt water species water loss must be minimized and preservation of ions would be a disadvantage, therefore they have a shortened labyrinth. Excre ion may also be a function of the coxal glands. The lateral gland may possibly function as an endocrine gland involved with production of a molting hormone. The rostral glands in inferior oribatids may have a salivary function. 5. The coxal glands of Peripatus, some millipedes, apterygote insects, decapod crustaceans, and all arachnid orders are homologous. The Tetrastigmata, Notostigmata, Cryptostigmata, and soft ticks have typical arachnid coxal glands. The coxal glands of higher Prostigmata may be modified into salivary, silk, or venom glands. The coxal glands in Mesostigmata, Astigmata, and hard ticks are lacking or highly modified.     

Comparative morphology, homologies, and functions of the male system in oribatid mites (Arachnida: Acari)

The penis is basically a double-walled oval cone. The weak type penis (only 2 species) has a weak tongue, lacks a bridge, and is elongate. The strong type (all others) has a bridge, a strong tongue, thicker walls, and is short. An accessory gland and a common vas deferens always open into the inner cup lumen (= ejaculatory duct). The massive tongue muscles may open the penal orifice. A pair of penal retractor muscles originate on the body wall. Penal protrusion and perhaps partial extrusion of stalk substance is by hemolymph pressure. The penis is completely homologous to the ovipositor. The genital discs are cuticular cups containing glandular tissue and are retractible by muscles originating on the body wall. The minute, rod-like, immobile sperm are mixed with seminal fluid and stalk material secreted by seminal vesicle cells. This mixture is carried via the vase deferentia by peristalsis to the penis. Semen and stalk substance (protein) are somehow separated in the ejaculatory duct into separate pools, with stalk substance nearest the penal orifice. Upon penal protrusion, a bit of stalk material is extruded and fastened to the ground, and upon raising of the mite's body the stalk is “drawn out.” Finally, the ball of semen, adhering to the stalk tip, is pulled through the penal orifice.     

Oribatid mite (Acari, Oribatida) feeding on ectomycorrhizal fungi

The coexistence of a large number of soil animals without extensive niche differentiation is one of the great riddles in soil biology. The main aim of this study was to explore the importance of partitioning of food resources for the high diversity of micro-arthropods in soil. In addition, we investigated if ectomycorrhizal fungi are preferentially consumed compared to saprotrophic fungi. Until today, ectomycorrhizal fungi have never been tested as potential food resource for oribatid mites. We offered six ectomycorrhizal fungi [Amanita muscaria (L.) Hook., Boletus badius (Fr.) Fr., Cenococcum geophilum Fr., Laccaria laccata (Scop.) Fr., Paxillus involutus (Batsch) Fr. and Piloderma croceum J. Erikss. & Hjortstam], one ericoid mycorrhizal fungus [Hymenoscyphus ericae (D.J. Read) Korf & Kernan] and three saprotrophic fungi [Agrocybe gibberosa (Fr.) Fayod, Alternaria alternata (Fr.) Keissl. and Mortierella ramanniana (A. Møller) Linnem.] simultaneously to each of the mainly mycophagous oribatid mite species Carabodes femoralis (Nicolet), Nothrus silvestris Nicolet and Oribatula tibialis Nicolet. The ericoid mycorrhizal fungus H. ericae and the ectomycorrhizal fungus B. badius were preferentially consumed by each oribatid mite species. However, feeding preferences differed significantly between the three species, with O. tibialis being most selective. This study for the first time documented that oribatid mites feed on certain ectomycorrhizal fungi.     

New Species of Oribatid Mites (Acari,Oribatida) from Sakhalin Island

Entomological Review - Two new oribatid mite species collected in the park zone of Yuzhno-Sakhalinsk (Sakhalin Island, Russia) are described. Xenillus similis sp. n. is a large pale brown mite with...     

Fine structure of the genital system in the females of Pergamasus mites (Acari: Gamasida: Pergamasidae)

The female reproductive system in Pergamasus mites consists of an unpaired vagina, vaginal duct, uterus, and ovary. Additionally, there are paired vaginal glands, as well as unpaired ventral and paired lateromedial glandular complexes. The vagina and vaginal duct are cuticle‐lined. In the dorsal wall of the vagina, this lining forms the endogynium which possesses a “sac” and two conspicuous “spherules” and is armed with “stipula” and other cuticular protrusions. The endogynium functions as a spermatheca, being a storing site for the spermatophore. The spherule procuticle is perforated by microvilli of underlying cells that are structurally very unusual. The lining of the vaginal duct forms numerous cuticular fibers directed toward the vagina. There is an external layer of muscles, supposedly functioning as a sphincter. The uterus is an organ in which the fertilized egg is stored for some time and starts embryonic development. Its wall is composed of glandular epithelial cells. The ovary consists of inner and outer parts. The former part is formed by a nutritive syncytium, whereas the latter contains growing oocytes. Two groups of glands connect with the genital tract. Paired vaginal glands are composed of glandular and secretion‐storing parts and open into the vagina. Paired lateromedial and unpaired ventral glandular complexes empty into the genital tract between the vaginal duct and uterus. The structure of the female genital system is discussed in terms of its function and phylogeny. J. Morphol. 240:195–223, 1999. © 1999 Wiley‐Liss, Inc.     

The structure of ovipositors in higher oribatid mites (Acari,Oribatida, Brachypylina)

Specific features of the morphology of the ovipositor (general shape, size, proportions, chaetome, etc.) were studied in 60 species of higher oribatid mites. The characteristics which can be used for identification of supraspecific taxa are distinguished.     

Seasonality of some Chihuahuan Desert soil oribatid mites (Acari: Cryptostigmata)

1. Reproductive strategies of four species of oribatid mites were investigated in the Chihuahuan Desert from 1981 to 1984.
2. Breeding activity coincided with the summer rainfall period in three of the four cases: Passalozetes neomexicanus, P. californicus and Jornadia larreae. This pattern was not changed by the application of simulated rainfall at other times of the year. The strict seasonality of reproductive behaviour is interpreted as an outcome of strong selection pressure to recruit only when food quality and quantity and microclimate are most favourable.
3. Joshuella striata showed a more flexible pattern which was essentially bimodal. Periods of egg production occurred in winter and also during the summer rainfall period. This pattern is consistent with the known distribution of this species in winter- and summer-rainfall deserts in south-western USA.     

Fine structure of the spermatophore and spermatozoa in inseminated females of Pergamasus mites (Acari: Gamasida: Pergamasidae)

This study describes the spermatophore of Pergamasus mites after transfer into the female endogynial sac and modifications of the structure of the female-penetrating spermatozoa. The spermatophore is saccular and contains largely unmodified spermatozoa and variously structured secretions. The spermatozoa that leave the spermatophore reach the inner (proximal) end of the vaginal duct where they presumably escape from the genital tract to continue their route through the hemocoel into the ovarian tissue where fertilization occurs. During this transit, the structure of such spermatozoa changes considerably, in particular when in contact with the ovary. These alterations include modifications of the cell periphery and of certain inclusion bodies. Furthermore, the spermatozoa form protrusions that fit into corresponding invaginations of the somatic tissue of the ovary.     

The camerobiid mites (Acari, Camerobiidae) of Turkey

Three new species of Neophyllobius viz. N. demirsoyi, N. yunusi, N. bolvadinensis and male, protonymph and larvae of N. lachishensis Bolland, 1998 from Turkey are described and illustrated. Neophyllobius lachishensis is reported from Turkey for the first time.     

革螨的异形(蜱螨亚纲)

在检视大量革螨标本中,发现异形标本４种９例。异形包括骨板变形和刚毛变位两种情况,现分别记述如下,供革螨分类鉴定和形态学研究时参考。１ 毒厉螨 Ｌａｅｌａｐｓ ｅｃｈｉｄｎｉｎｕｓ Ｂｅｒｌｅｓｅ,１８８７ 检视标本１６０８■■,发现异形４■■。１９７１年２-１０月采于吉林省前郭尔罗斯蒙古族自治县,寄主为褐家鼠 Ｒａｔｔｕｓ ｎｏｒｕｅｇｉｃｕｓ（Ｂｅｒｋｅｎｈｏｕｔ）。 标本１：胸板后缘明显凹陷,后凸的骨片消失（图１-２）,该处构造与正常标本不同。肛板花纹如图１,后部有一圆锥形构造,向后突出,ＰＡ位于其后…