Species richness of soil gamasid mites (Acari: Mesostigmata) in fire-damaged mountain sites

Gamasid mites are important regulators of soil food webs in forest ecosystems. Wildfire is a dominant disturbance factor in forest ecosystems. We assessed the impact of fire on the species composition of soil gamasid mites at mountain sites following fires of four different degrees of severity and at one control site (5 years post-fire). In total, 14 families, 28 genera, and 54 species or species complexes were found. The abundance and richness were poor in severely burned sites compared to the less damaged sites. The different species compositions, especially in the medium-burned site, require further ecological study to improve our understanding. The fire response and recovery processes of selected species are also discussed.     

The diversity of soil mites (Acari: Mesostigmata) in yellow ant (Lasius flavus) nests along a gradient of land use

Mesostigmatid mites communities in yellow ant (Lasius flavus) hills and phoresis of mites on this ant species were analysed in the Wielkopolska Region, Central Poland. Samples were collected from ant nests located along a gradient of four different types of land use: forest, ecotone, meadow and garden. In total, 132 mites were collected in ant nests among which 26 species were identified. The highest total abundance of mites was observed in the ecotone. Moreover, 14 mite specimens were found on L. flavus workers bodies. These are the first records of phoresis of mesostigmatid mites on this ant species.     

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.     

吉林省革螨新记录(蜱螨亚纲:中气门目)

本文报道吉林省革螨新记录4种。1裂胸螨科(Aceosejidae) 1.1巨肛伊虫穴螨(Iphidozercon magnanalis Ma et Yin,1999)雌螨体长494μm,宽287μm。背板覆盖整个背面,边缘稍卷向腹面;板面花纹浓重,凸凹不平,前部与两侧呈网状,网眼形状不规则,中部形成纵带,带上有许多小圆孔;背毛短小光滑。胸板前后缘均凹,胸毛3对。生殖板后部稍膨大,生殖毛在板外。肛板宽大于长,后部宽于前部,前后缘均凸。气门沟前端达到颚基。头盖3突。螯钳动趾2齿。     

中国革螨新记录(2)(蜱螨亚纲:中气门目)

报道中国革螨16新记录.     

Unstable microhabitats (merocenoses) as specific habitats of Uropodina mites (Acari: Mesostigmata)

Unstable microhabitats (merocenoses)—such as decayed wood, ant hills, bird and mammal nests—constitute an important component of forest (and non-forest) environments. These microhabitats are often inhabited by specific communities of invertebrates and their presence increases the total biodiversity. The primary objective of the present study was to compare communities of Uropodina (Acari: Mesostigmata) inhabiting soil and unstable microhabitats in order to explore the specificity of these communities and their importance in such ecosystems. Uropodine communities inhabiting merocenoses are often predominated by one or two species, which constitute more than 50 % of the entire community. Many species occur commonly in particular merocenoses, but are absent or rare in soil and litter, for example, Allodinychus flagelliger, Metagynella carpatica, Oplitis alophora, and Phaulodiaspis borealis. The biology of Uropodina inhabiting unstable microhabitats is modified by the adaptations required for living in such habitats. Mites associated with merocenoses developed special dispersal mechanisms, such as phoresy, which enable them to migrate from disappearing environments. Communities of Uropodina in soil and litter predominately consisted of species which reproduce parthenogenetically (thelytoky), whereas in merocenoses bisexual species prevail.     

Morphological diversity of pedicels in phoretic deutonymphs of Uropodina mites (Acari: Mesostigmata)

The pedicel is a structure that connects the phoretic deutonymph of Uropodina mites with its carrier and enables dispersal. The shapes, lengths and diameters of pedicels formed by Uropoda orbicularis, Trichouropoda ovalis, Uroobovella pulchella and Uroobovella nova were studied by scanning and light microscopy. Pedicels of U. orbicularis and T. ovalis have the shape of a straight stalk. In U. pulchella, the pedicel is extremely short, irregularly shaped and composed of homogeneous material. The longest pedicel is found in U. nova and it may be helically coiled in this species. The length of the pedicel is positively correlated with deutonymph body size between species, but not within species. Pedicels of U. orbicularis and U. pulchella have the largest diameter. The pedicel diameter in U. orbicularis and T. ovalis is inversely proportional to its length, but not in U. nova and U. pulchella. The constituent of pedicel stems in U. pulchella is homogeneous, whereas in U. orbicularis and T. ovalis it contains a bundle of tightly packed fibres. In U. nova coiled pedicels are comprised of two layered materials of different electron density, one of which is electron lucid and located peripherally. Hypotheses on the origin of the pedicel are proposed.     

Phytoseiid mites (Acari: Mesostigmata) associated with tea gardens in north of Iran

Predator mites of Phytoseiidae family are among the most important biocontrol agents in the world. These beneficial mites are considered as natural enemies of many pests and herbivore mites, and can feed on different growth stages of pests (egg, larva or nymph). Five species of Phytoseiidae mites were found during a survey conducted on tea plants, Camellia sinensis (Theaceae), in the Mazandaran and Guilan Provinces in the north of Iran, on the coast of the Caspian Sea, the major tea-growing region of Iran. Some of these species are recorded for the first time in tea gardens of Iran.     

Community structure and dispersal of mites (Acari, Mesostigmata) in nests of the white stork (Ciconia ciconia)

The fauna of Mesostigmata in nests of the white stork Ciconia ciconia was studied in the vicinity of Poznań (Poland). A total of 37 mite species was recovered from 11 of the 12 nests examined. The mite fauna was dominated by the family Macrochelidae. Macrocheles merdarius was the most abundant species, comprising 56% of all mites recovered. Most of the abundant mite species were associated with dung and coprophilous insects. It is likely that they were introduced into the nests by adult storks with dung as part of the nest material shortly before and after the hatching of the chicks.     

New findings of gamasid mites belonging to families Laelapidae,Hirstionyssidae, and Haemogamasidae (Acari: Mesostigmata: Gamasina) on bats (Chiroptera)

Our own and previous data concerning the findings of parasitic gamasid mites (Mesostigmata: Gamasina) on bats (Chiroptera), which are not a principal host for them, are analyzed. The gamasid mites under study belong to the following families: Laelapidae Berlese, 1892; Hirstionyssidae Evans, Till, 1966; and Haemogamasidae Oudemans, 1926. In total, 27 species of parasites of the analyzed groups were found on bats. Among them, two species were described for bats for the first time. The medicinal value of this exchange is considered. Possible places where bats have contact with other mammals are discussed.     

Exploring the growth response of Norway spruce (Picea abies) along a small-scale gradient of soil water supply

The climate-growth response of specific sites and species is one of the main research subjects in classic tree ring studies. Traditional sampling approaches therefore aim at maximizing the climate signal of the analyzed tree ring series, which is typically achieved by focusing on dominant trees or on sites located in particularly temperature or moisture limited environments. However, there is increasing evidence that these selective sampling strategies cannot yield chronologies that are representative for entire populations. One promising approach to gain a deeper understanding of forest dynamics and climate-growth responsiveness is the analysis of climate signal ranges among trees. This individualistic approach requires random sampling and the integration of information on small-scale heterogeneities in site and tree characteristics. Here, we analyze the climate-growth response of 144 Norway spruce trees (Picea abies Karst.) on difference levels of data aggregation. The aim of our study is to investigate the relevance of small-scale heterogeneities in site conditions, particularly in soil water supply, for the detected climate-growth signal. We identify soil water supply and site characteristics, which indirectly modify the water availability for trees, as dominating growth factors across scales. The driest sites show the strongest climate-growth reaction, while the growth response of wetter sites is weak or even insignificant. Therefore, we conclude that integrating small-scale information on site characteristics, particularly on soil water supply, can help to gain a deeper understanding of species specific growth limitations.     

Evaluation of predatory mite (Acari: Phytoseiidae) releases to suppress spruce spider mites, Oligonychus ununguis (Acari: Tetranychidae), on juniper

A laboratory trial evaluated four phytoseiid species for their potential as biological control agents of spruce spider mite, Oligonychus ununguis (Jacobi) (Acari: Tetranychidae). An augmentative biological control approach, using the predatory mites Neoseiulus fallacis Garman and Galendromus occidentalis Nesbitt (Acari: Phytoseiidae), was evaluated for reducing pest mite densities and injury, and economic costs on Juniperus chinensis 'Sargentii' A. Henry (Cupressaceae) in an outdoor nursery. Sequential releases of predator species, individually and in combination, were tested and compared with two commonly used miticides, a low-toxicity miticide, horticultural oil, and a conventional miticide, hexythiazox. Timing of treatments was based on grower-determined need, and predator release rates were based on guidelines in literature received from producers of beneficial organisms. Predator releases were more expensive and provided less effective suppression of spruce spider mites, resulting in greater spider mite injury to plants, compared with conventional pesticides. However, spider mite damage to plants did not differ in an economically meaningful way between treatments. Unsatisfactory levels of control seem related to under estimations of actual spider mite abundance based on grower perceptions and the beat sampling technique used to estimate predator release rates. These data suggest that when initial populations of spruce spider mite are high, it is unlikely that sequential releases of predator species, individually or in combination, will suppress spider mite populations. In this trial, augmentative biological control control was 2.5-7 times more expensive than chemical controls.     

Communities of uropodine mites (Acari: Mesostigmata) in selected oak-hornbeam forests of the Wielkopolska region (Poland)

Pristine oak-hornbeam forests are among the richest flora and fauna environments in Poland. The agricultural development of the Wielkopolska region has led to the replacement of forest area with farmland. Consequently, the oak-hornbeam forests became fragmented, resulting in the isolation of local arthropod populations. The aim of this study was to compare the communities of uropodine mites in selected parts of a forest, differing in stand age and composition, physical soil condition and degree of anthropogenic pressure. Species composition of mite communities in a forest near Duszniki (West Poland), transformed by humans, was compared with the mite species composition observed in three nature reserves in its close vicinity. The analyses showed that Trachytes aegrota and Olodiscus minima constitute more than 50% of all communities in each type of tree stand. Diversity in Uropodina communities was higher in older tree stands, as well as in protected areas. Some species, such as Uroobovella pulchella, Uroobovella pyriformis and Dinychus woelkei, are related to specific microhabitats (e.g., they inhabit only dead wood) but there are also ubiquitous species, occurring in all types of environment, e.g., Oodinychus ovalis. Species like Oodinychus karawaiewi and Dinychura cordieri indicate a high degree of forest disturbance. Presence of such species as Trachytes lamda, Cilliba rafalskii, Cilliba cassideasimilis and Trematurella elegans points at high naturalness of soil in oak-hornbeam forests. These species have been found in old (>100 years old) tree stands, where Uropodina communities were also the richest.     

Nests of the black stork Ciconia nigra as a habitat for mesostigmatid mites (Acari: Mesostigmata)

We surveyed the Mesostigmatid mite fauna of nests of the black stork Ciconia nigra, to determine the role of these mites in the biology of their hosts. We present preliminary results obtained on the basis of material collected from 31 nests. A total of 1,615 mite specimens was recorded, belonging to 39 species. The most abundant species were Dendrolaelaps strenzkei, Apionoseius infirmus, Macrocheles merdarius and Macrocheles ancyleus, which constituted more than 65% of all the specimens recorded. The presence of large numbers of predatory mites could be beneficial to the birds, if they feed on the eggs and larvae of the bird’s parasites. It is likely that many of the mite species found in these nests were carried there by phoresy on insects, mainly Coleoptera.