Gallogenesis induced by eryophyoid mites (Acariformes: Eriophyoidea)

Entomological Review - A review of the latest data on the problem of gall formation on plants under the influence of eryophyoid mites of the superfamily Eriophyoidea is given. Gall formation is...     

Distribution of eriophyoid mites (Acari: Eriophyoidea) on coniferous trees

The aim of the paper was to determine the infestation parameters and species composition of eriophyoid mites for different parts of Norway spruce and Scots pine as well as for different age groups of the trees. The observations on the occurrence of the mites were conducted in 2004 and 2005 in 4 locations distributed in various regions of Poland, accounting for 11 environments (location x year). Three plant age groups were studied: (1) adult trees: 40–60 years old, additionally divided into three levels: top, middle and bottom; (2) young trees: 6–10 years old; and (3) seedlings: 2–3 years old. The same number of species (five) occurred on each coniferous tree, but only one, the rarest, was common on both tree species. Out of 500 samples for each species, mites were found on 279 pine (55.8%) and 252 spruce samples (50.2%). No tendency for the mites to choose any particular level on Scots pine and Norway spruce was observed. In addition, no tendency for the mites to choose trees from any of the age groups was observed for both Scots pine and Norway spruce, in the latter case the result obtained also for mite species subdivided into vagrant and refuge-seeking ones. Final conclusions were that in case of adult trees samples can be taken from the bottom part of a tree; however, sampling from young trees growing among adult trees may be seen as the most efficient sampling method.     

Successions of oribatid mites (Acariformes: Oribatida) on disturbed areas

During recovery succession, structural and functional changes in oribatid mite communities occur: the number of species increases, the structure becomes more complex, the proportion of surface-living and nonspecialized forms increases, and the role of parthenogenetic species decreases. The direction of succession is to form a community characteristic of the zonal type of vegetation. Four stages are selected. The colonization-accumulation stage involves the initial accumulation of organic matter due to activity of microorganisms. Oribatids are not numerous at this stage. The unstructured stage is characterized by unstable monodominant communities of parthenogenetic oribatids with short life cycles. The next stage is structuring, when the proportion of parthenogenetic forms decreases, and that of nonspecialized forms increases. Communities are monodominant. The final stage is stabilization. The proportion of parthenogenetic species decreases noticeably. The generic and species composition of the communities stabilizes. The community achieves zonal features.     

Predation and mycophagy by endeostigmatid mites (Acariformes: Prostigmata)

The endeostigmatid mitesAlicorhagia fragilis andAlycus spp. are nematophages. Nematodes are cut up by the chelicerae or ingested whole, but are difficult to recognize as gut contents.Alycus roseus is a strict predator and does not consume microphytes.Alicorhagia fragilis is an omnivore. When nematodes are not available, adult females consume more fungi, but lay significantly fewer eggs, and cultures eventually decline to extinction.Observations of gut contents from 18 genera in ten families indicate that species in the families Terpnacaridae, Grandjeanicidae, Lordalycidae, Micropsammidae, and Oehserchestidae are primarily particulate-feeding fungivores. The families Namorchestidae and Nematalychidae are apparently fluid feeders. Species of Alicorhagiidae are best considered omnivores. In the family Bimichaelidae (=Pachygnathidae)_species with chelate-dentate chelicerae (Alycus, Petralycus, somePachygnathus) are predators of soft-bodied microinvertebrates. Species with attenuate, highly modified chelicerae (e.g.Bimichaelia) have unknown feeding habits. Alicorhagia fragilis spins a silken thread from its oral cavity with which immatures weave a molting cocoon and with which females weave a platform on which their eggs are laid.     

Gonads and gametogenesis in astigmatic mites (Acariformes: Astigmata)

Astigmatans are a large group of mites living in nearly every environment and exhibiting very diverse reproductive strategies. In spite of an uniform anatomical organization of their reproductive systems, gametogenesis in each sex is highly variable, leading to gamete formation showing many peculiar features and emphasizing the distinct position of Astigmata. This review summarizes the contemporary knowledge on the structure of ovaries and testes in astigmatic mites, the peculiarities of oogenesis and spermatogenesis, as well as provides new data on several species not studied previously. New questions are discussed and approaches for future studies are proposed.     

Structure of eyes in trombidioid mites (Acariformes: Trombidioidea)

The eyes or ocelli of trombidioid mite larvae of Euschoengastia rotundata, Hirszutiella zachvatkini and Camerotrombidium pexatum, and larvae and adults of Platytrombidium fasciatum were studied by means of transmission electron microscopy. These species together with larvae of Odontacarus efferus, Ericotrombidium hasgelum, Walchia chinensis and adult E. rotundata and H. zachvatkini were also studied under scanning electron microscope. The eyes of larvae are not inverted and characterized by an epicuticular lamellar lens. The group of phoreceptor cells with rhabdomeres arranged typically of Chelicerata is underlaid by a pigment cup. The eyes of adult mites are inverted, perikarions of photoreceptor cells are situated between the lens and rhabdomeres; tapetum occupies the space between the pigment cup and rhabdomeres. Sensitivity of eyes to light is similar to that of primary eyes of spiders dwelling on soil surface.     

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.     

Eriophyoid Mites (Acariformes,Eriophyoidea) from Rosaceae: Taxonomic Diversity,Host-Parasite Relationships,and Ability to Cause Galls

A review on the complex of species of eriophyoid mites associated with Rosaceae is given, focused on the phylogeny, biology, and distribution of their host plants and galls induced by these mites. About 200 species of 39 genera from 3 families ofEriophyoidea are known from Rosaceae. Among them, 6 species from 2 genera belong to Phytoptidae, 178 species from 27 genera, to Eriophyidae, and 28 species from 10 genera, to Diptilomiopidae; 7 genera of the latter family are represented on Rosaceae by a single species each. The ability to induce galls is discussed using the example of the most widespread and numerous genera of the family Eriophyidae from Rosaceae. Mites of two large subfamilies, Eriophyinae and Phyllocoptinae, include both vagrant and concealed forms. The types of galls caused by mites are related to the systematic position of mites and the distribution of mites and their host plants. The hypothesis of host shifts of eriophyoid mites from other plant families to Rosaceae is considered. Most of the species which presumably switched to Rosaceae have been described from Southeast Asia. Morphological similarity between vagrant and concealed forms from the paraphyletic tribes Eriophyini and Phyllocoptini, and also Aceriini and Anthocoptini is discussed. Their pairwise similarity might be the result of evolution (Eriophyini → Phyllocoptini and Aceriini → Anthocoptini) connected with change oflife style.     

Modern conceptions concerning the macrophylogeny of acariform mites (Chelicerata,Acariformes)

Modern conceptions concerning the macrophylogeny of acariform mites assumed during the last thirty years are summarized. Arguments supporting the hypothesis assuming the monophyly of mite taxa of higher taxonomic ranks (above the superfamily level) are discussed. The main unsolved problems of the phylogeny of the order Acariformes are mentioned. A new provisional classification of the order Acariformes for the taxa ranking from the suborder to the superfamily is proposed.     

Morphology of Parasitengona mites (Acariformes: Parasitengona) and their possible evolutionary scenario

On the basis of the analysis of morphology and biology of representatives of the Parasitengona, mostly trombiculids, trombidiids and water mites, a new attempt is made to clarify probable evolutionary scenario in this group of the higher trombidiform mites (Actinedida). It is supposed that the very old ancestral group of terrestrial arachnids, having bite-sucking mouth-parts, poorly differentiated sac-like midgut and capability to extra-oral digestion, fed predatory on different small soil arthropods at all phases of the life cycle. They were small segmented orthotrichous homeomorphic arachnids at the rank of genus or family. The favorable feeding conditions of the adult phase have led to the small eggs rich in yolk and the small larva. The latter have led in turn to the necessity of intensive feeding at the larval stage to complete the ontogenesis. Further in evolution, this group gave rise at once to two or even more large paraphyletic branches. Most of them retained feeding on arthropods with transition of larvae to much more effective parasitic feeding provided with the additional specialization of the larval stage. This branch comprise divergently radiated paraphyletic terrestrial and secondary-water water mites each having long course of evolution resulted in the recent groups of Calyptostomatoidea, Erythraeoidea, Trombidioidea and several superfamilies of water mites. Another branch of the ancestral Parasitengona has followed the way of adaptation of larvae to feeding on vertebrates, which were being attacked by the larvae in the environment of pasture. The parasitism on vertebrates has lead to several radical specializations of these mites and their significant evolutionary progress. At the same time, the similar ontogenetic dynamics, as well as synchronous reduction of particular developmental stages in all parasitengones, inevitably indicate the monophyletic origin of the whole branch of Parasitengona with Pterygosomatidae as the most probable sister group.     

Morphological adaptations of acariform mites (Acari: Acariformes) to permanent parasitism on mammals

The external morphological adaptations to parasitism in acariform mites (Acari: Acariformes), permanently parasiting mammals, are briefly summated and analyzed. According to several external morphological criteria (structures of gnathosoma, idiosoma, setation, legs and life cycle), the following six morphoecotypes were established: skin mites (i)-- Cheyletidae, Chirorhynchobiidae, Lobalgidae, Myobiidae, Myocoptidae (the most part), Rhyncoptidae, Psoroptidae; fur mites (ii)--Atopomelidae, Clirodiscidae, Listrophoridae, Myocoptidae (Trichoecius only); skin burrowing mites (iii)--Sarcoptidae; intradermal mites (iv) - sorergatidae and Demodicidae; interstitial mites (v) - pimyodicidae; respiratory mites (vi) - reynetidae, Gastronyssidae, Lemurnyssidae, Pneumocoptidae. In the case of prostigmatic mites, the detailed reconstruction of the origin and evolution of "parasitic" morphoecotypes is possible due to the tentative phylogenetic hypotheses, which were proposed for the infraorder Eleutherengon, a, including the most part of the permanent mammalian parasites among prostigmatic mites (Kethley in Norton, 1993; Bochkov, 2002). The parasitism of Speleognathinae (Ereynetidae) in the mammalian respiratory tract arose independently of the other prostigmats. It is quite possible that these mites switched on mammals from birds, because they are more widely represented on these hosts than on mammals. The prostigmatic parasitism on mammalian skin seems to be originated independently in myobiids, in the five cheyletid tribes, Cheyletiellini, Niheliini, and Teinocheylini, Chelonotini, Cheyletini, and, probably, in a cheyletoid ansector of the sister families Psorergatidae-Demodicidae (Bochkov, Fain, 2001; Bochkov, 2002). Demodicids and psorergatids developed adaptations to parasitism in the skin gland ducts and directly in the epithelial level, respectively in the process of the subsequent specialization. Mites of the family Epimyodicidae belong to the phylogenetic line independent of other cheyletoids. These mites possess the separate chelicerae and, therefore, can not be included to the superfamily Cheyletoidea. It is not quite clear whether they were skin parasites initially or they directly switched to parasitism from the predation. The phylogeny of sarcoptoid mites (Psoroptidia: Sarcoptoidea) is not developed, however, some hypotheses about origin and the following evolution of their morphoecotypes can be proposed. We belive that astigmatic mites inhabiting the mammalian respiratory tract transferred to parasitism independently of other sarcoptoids. The idiosoma of these mites is not so much flattened dorso-ventrally and has proportions which are similar to hose of free-living astigmatids. Moreover, in the most archaic species, the legs are not shortened or thickened as in the most parasites. The disappearance of many morphological structures in these mites, probably, happened parallely with some other sarcoptoids due to their parasitic mode of life. The skin inhabiting sarcoptoids belong to the "basic" morphoecotype, and all other sarcoptoid morphoecotypes, excluding respiratory mites, are derived from it. Some mites of this morphoecotype live on the concave surfaces of the widened spine-like hairs of the rodents belonging to the family Echimyidae (mites of the subfamily Echimytricalginae), in the mammalian ears (some Psoroptidae) or partially sink into the hair follicles (Rhynocoptidae). Finally, mites of the family Chirorhynchobiidae live on the bat wing edges attaching to them by their "ixodid-like" gnathosoma. The fur-sarcoptoids, probably, originated from the skin mites. This morphoecotype is divided onto two subtypes: mites with the dorso-ventrally flattened idiosoma (subtype I) and mites with the teretial idiosoma (subtype II). Each "fur-mite" family includes mites of the both subtypes. All mites of the first subtype belong to the early derivative lineages in their families. Among listrophorids such early derivative lineage is represented by the subfamily Aplodontochirinae (Bochkov, OConnor, 2006), and among Chirodiscidae--by mites of the subfamilies Chirodiscinae, Schizocoptinae, and Lemuroeciinae. Among the "fur" astigmatid families, the family Atopomelidae. probably, is the most archaic, and the most part of atopomelids belongs to the first subtype. However there are several more specialized atopomelid genera belonging to the second subtype, Atopomelus, Dasyurochirus, Lemuroptes, Murichirus, Metachiroecius etc. We believe that mites of the first subtype are represented by the "intermediate" forms between skin mites and mites of the second subtype. Some skin sarcoptoids transferred from skin parasitism to burrowing of the host skin (Sarcoptidae). The established morphoecotypes are partially corresponding to some morphoecotypes established by Mironov (1987) for feather mites. Our morphoecotypes of skin and skin burrowing mites perfectly correspond to Mironov's epidermoptoid and knemidocoptoid morphoecotypes, respectively. The proctophylloid morphoecotype (mites living on the wing feathers), which is the most widely represented within feather mites, has an analogy among mammalian mites - the subfamily Echimytricalginae. The analgoid (mites living in the down feathers) and dermoglyphoid (mites living in the feather quills) morphoecotypes have no analogues among mammalian mites for the obvious reasons. It is interesting why some microhabitats on the host body are not still occupied by prostigmatic or astigmatic mites. We believe that the nutrition is the main limitative factor here. The parasitic prostigmates evolved from predators and, therefore, feed on content of the living cells. They need the direct contact with the live tissues of the host and they belong, therefore, to the morphoecotypes represented by the respiratory, skin, gland duct, intradermal, and interstitial mites. Whereas, the most part of the skin inhabiting astigmats feed on the dead epithelial scales. For this reason these mites, so easily colonized fur of their hosts and feed on the hair grease there. On the other hand, some sarcoptoids transferred to the true parasitism and feed on the cambial cells of the skin epithelium. More over we do not know exactly about nutrition of rhyncoptids yet.     

中国广西大瑶山瘿螨新属和新种（蜱螨亚纲：瘿螨总科）

记述采自广西的瘿螨总科10属10新种。新属二环顶背瘿螨属Tegosecanus gen. nov. 的主要属鉴别特征为：螨体为纺锤形,胛毛位于盾后缘之前,螨体背环光滑,腹环具微瘤,背环具中纵脊,终止于2侧脊之前,第2背环宽,覆盖于其后的二背环之上,第3–4背环具侧突。10新种分别是：油杉三毛瘿螨Trisetacus fortunei sp. nov.;桂林雕瘿螨Glyptacus kweilinensus sp. nov.;腺叶桂樱新拟尖叶瘿螨Neoacaphyllisa phaeosticta sp. nov.;山黄麻尖空瘿螨Oxycenus tomentosae sp. nov.;拟赤杨小叶剌瘿螨Phyllocoptacus fortuneir sp. nov.;金秀二环顶背瘿螨Tegosecans jinxiuensis sp. nov.;古柯上瘿螨Epitrimerus sinensis sp. nov.;润楠叶剌瘿螨Phyllocoptes glaucifoliae sp. nov.;山麻风羽爪瘿螨Diptilomiopus pomiferae sp. nov.;卫矛维氏瘿螨Vimola laxifloris sp. nov. 上述所有瘿螨新种均生活在寄主叶片背面,无明显为害状。     

Extra-oral digestion and the problem of parasitism in Parasitengona mites (Acariformes)

An analysis of the extra-oral digestion in Parasitengona being a highly specialized group of Acariform mites is carried out from the viewpoint of functional morphology and ecology. The significance of the extra-oral digestion in the life strategy of these mites and their larval parasitism is also evaluated. The morphological pre-adaptations of this mode of feeding as well as its probable evolutionary consequences are demonstrated by an example of trombiculid mites (Trombiculidae). It is shown, in particular, that parasitism in general may be considered as a particular life scenario implying that the feeding preferences of the organism are evolutionary formed in a close association with other organisms, which provide a parasite with a feeding substrate mainly already prepared for utilization. Based on this assumption, all Parasitengona, including both larval and post-larval instars, irrespectively of the size of their potential victim, preferably should not be considered as parasites, but as micro-predators.