植绥螨科线粒体基因组研究进展

植绥螨科属于囊螨总科,大部分植绥螨为害螨、害虫的重要天敌,在农业生产上具有重要的应用价值。其线粒体基因组具有独特特征,引起了生物学家的广泛关注。本文就植绥螨科线粒体基因组的结构、非编码区、碱基组成、基因重排和tRNA的特征进行综述,其特征有：（1）植绥螨科中发现了螯肢动物最大的线粒体基因组;（2）植绥螨科线粒体基因组非编码区的AT含量差异大,编码区的AT含量差异小;（3）植绥螨科线粒体基因组均发生了不同程度的的基因重排;（4）已测定的植绥螨科部分物种tRNA基因二级结构出现了截短和碱基错配的现象,部分物种的线粒体基因组出现反密码子突变的情况。在今后的研究中应进一步测定植绥螨科关键类群的线粒体基因组,深入分析植绥螨科出现大量基因重排的原因,以期能反映植绥螨科的真实进化历程。     

Diversity of phytoseiid mites (Acari: Mesostigmata: Phytoseiidae) in the Atlantic Forest of São Paulo

The objective of this study was to evaluate the diversity of Phytoseiidae in the Atlantic Forest of São Paulo State, Brazil, and to estimate the possible role of this ecosystem as a reservoir for mites of this family. Samples were taken from 187 plant species belonging to 73 plant families in three vegetation types of the Atlantic Forest, from February 2001 to October 2002. In total, 1102 specimens of 54 species belonging to 20 genera of the three phytoseiid subfamilies were found. Most specimens (93%) and species (91%) belonged to the Amblyseiinae. The majority of species found belong to taxonomic groups largely composed of generalist predators (especially Amblyseius and Euseius). In general, the more abundant mites were found on a diversity of plant species, but a few of the abundant species were found on only a small number of plant species. Only nine of the mites encountered during this study are of known agricultural importance. The results obtained suggest the importance of the wide plant diversity in the region to sustain a wide diversity of phytoseiids. The extensive clearance of the Brazilian Atlantic Forest is a threat to the diversity of these mites, important predators of mite pests.     

Mitochondrial genome reorganization characterizes various lineages of mesostigmatid mites (Acari: Parasitiformes)

Mesostigmata is an extremely diverse group of mites with more than 11,000 described species in 109 families. The complete mitochondrial (mt) genomes of five species of mesostigmatid mites from three families (Varroidae, Ologamasidae, Phytoseiidae) have been reported previously; all of them are rearranged or highly rearranged in gene order. However, it is unclear when mt genome reorganization occurred and how common it is in mesostigmatid mites. We sequenced the mt genomes of ten species of mesostigmatid mites from five more families (Blattisociidae, Diplogyniidae, Laelapidae, Macrochelidae, Parasitidae). We found that species in the families Diplogyniidae and Parasitidae have retained the ancestral mt genome organization of arthropods, which is in stark contrast to the highly rearranged mt genomes in the Phytoseiidae species. As in the Varroidae and Ologamasidae species, the mt genomes of the Blattisociidae, Macrochelidae and Laelapidae species are also rearranged but are less rearranged than in the Phytoseiidae species. Each of the six mesostigmatid families that have rearranged mt genomes is characterized by unique gene order not seen in other mesostigmatid families. Furthermore, the mt genome organization also differs among three genera of the Phytoseiidae, between two genera of the Laelapidae, and among three Macrocheles species of the Macrochelidae. Our results indicate that: (a) the most recent common ancestor of mesostigmatid mites likely retained the ancestral mt genome organization of arthropods; and (b) mt genome organization characterizes various lineages of mesostigmatid mites and provides a valuable source of information for understanding their phylogeny and evolution.     

Functionally different predators break down antipredator defenses of spider mites

Prey that lives with functionally different predators may experience enhanced mortality risk, because of conflicts between the specific defenses against their predators. Because natural communities usually contain combinations of prey and functionally different predators, examining risk enhancement with multiple predators may help to understand prey population dynamics. It is also important in an applied context: risk enhancement with multiple biological control agents could lead to successful suppression of pests. We examined whether risk enhancement occurs in the spider mite Tetranychus kanzawai Kishida (Acari: Tetranychidae) when exposed to two predator species: a generalist ant, Pristomyrmex punctatus Mayr (Hymenoptera: Formicidae), and a specialist predatory mite, Neoseiulus womersleyi Schicha (Acari: Phytoseiidae). We replicated microcosms that consisted of spider mites, ants, and predatory mites. Spider mites avoided generalist ants by staying inside their webs on leaf surfaces. In contrast, spider mites avoided specialist predatory mites that intruded into their webs by exiting the web, which obviously conflicts with the defense against ants. In the presence of both predators, enhanced mortality of spider mites was observed. A conflict occurred between the spider mites’ defenses: they seemed to move out of their webs and be preyed upon by ants. This is the first study to suggest that risk enhancement occurs in web‐spinning spider mites that are exposed to both generalist and specialist predator species, and to provide evidence that ants can have remarkable synergistic effects on the biological control of spider mites using specialist predatory mites.     

Vertical distribution of three species of eriophyid mites on tea in south India

Two eriophyid mites,Acaphylla theae andCalacarus carinatus, have been known for some time as important pests of tea. In recent years a third eriophyid,Acaphyllisa parindiae, has also become abundant. The vertical distribution of these three species on tea is examined.     

Acarofauna present in organic strawberry fields and associated weed species in southern Brazil

The presence of weeds in the margins of strawberry crops can enhance populations of predatory mites as a measure to support conservation biological control. The aims of this study were (i) to assess the composition of the acarofauna associated with strawberries and the accompanying herbaceous plants in an organic farming system, and (ii) to evaluate the possible relationships between phytophagous and predatory mites occurring in this system. Strawberry leaves and whole plants of weeds were sampled biweekly from August 2014 to February 2015 in Lapa (Paraná, Brazil). In total, 23 weed species belonging to 10 families were identified; 3768 mite individuals (from 15 families and 4 suborders) were recovered, 77% on strawberries and 23% on weeds. Abundance of predatory mites on weeds was greater than on strawberry cultivars. On strawberries, the most abundant family was Tetranychidae (84%) followed by Phytoseiidae (11.6%). In total, 16 predatory mite species from the Phytoseiidae family were identified, 13 of them occurring on strawberry leaflets. Typholodromalus aripo, Neoseiulus californicus and Typhlodromips mangleae were the most abundant mite species on strawberry leaves. On weeds, most individuals were predatory mites (59%), whereas phytophagous mites represented 17.2%. The most abundant family was Phytoseiidae (36.4%). On weeds, the phytoseiid mite T. aripo was the most abundant species, representing 34.7%. Besides being found on strawberry leaflets, T. aripo was associated with 15 weed species. Among the weeds, Bidens pilosa showed the highest values of the Shannon index (1.97), Margalef index (3.04), and Pielou’s evenness index (0.95). This study emphasizes the importance of surrounding weeds as a shelter for beneficial mitefauna in strawberry fields, likely contributing to enhance conservation biological control.

     

Disentangling mite predator‐prey relationships by multiplex PCR

Gut content analysis using molecular techniques can help elucidate predator‐prey relationships in situations in which other methodologies are not feasible, such as in the case of trophic interactions between minute species such as mites. We designed species‐specific primers for a mite community occurring in Spanish citrus orchards comprising two herbivores, the Tetranychidae Tetranychus urticae and Panonychus citri, and six predatory mites belonging to the Phytoseiidae family; these predatory mites are considered to be these herbivores’ main biological control agents. These primers were successfully multiplexed in a single PCR to test the range of predators feeding on each of the two prey species. We estimated prey DNA detectability success over time (DS₅₀), which depended on the predator‐prey combination and ranged from 0.2 to 18 h. These values were further used to weight prey detection in field samples to disentangle the predatory role played by the most abundant predators (i.e. Euseius stipulatus and Phytoseiulus persimilis). The corrected predation value for E. stipulatus was significantly higher than for P. persimilis. However, because this 1.5‐fold difference was less than that observed regarding their sevenfold difference in abundance, we conclude that P. persimilis is the most effective predator in the system; it preyed on tetranychids almost five times more frequently than E. stipulatus did. The present results demonstrate that molecular tools are appropriate to unravel predator‐prey interactions in tiny species such as mites, which include important agricultural pests and their predators.     

Diseases of Mites

An overview is given of studies on diseases of mites. Knowledge of diseases of mites is still fragmentary but in recent years more attention has been paid to acaropathogens, often because of the economic importance of many mite species. Most research on mite pathogens concerns studies on fungal pathogens of eriophyoids and spider mites especially. These fungi often play an important role in the regulation of natural mite populations and are sometimes able to decimate populations of phytophagous mites. Studies are being conducted to develop some of these fungi as commercial acaricides.Virus diseases are known in only a few mites, namely, the citrus red mite and the European red mite. In both cases, non-occluded viruses play an important role in the regulation of mite populations in citrus and peach orchards, respectively, but application of these viruses as biological control agents does not seem feasible. A putative iridovirus has been observed in association with Varroa mites in moribund honeybee colonies. The virus is probably also pathogenic for honeybees and may be transmitted to them through this parasitic mite.Few bacteria have been reported as pathogens of the Acari but in recent years research has been concentrated on intracellular organisms such as Wolbachia that may cause distorted sex ratios in offspring and incompatibility between populations. The role of these organisms in natural populations of spider mites is in particular discussed. The effect of Bacillus thuringiensis on mites is also treated in this review, although its mode of action in arthropods is mainly due to the presence of toxins and it is, therefore, not considered to be a pathogen in the true sense of the word.Microsporidia have been observed in several mite species especially in oribatid mites, although other groups of mites may also be affected. In recent years, Microsporidia infections in Phytoseiidae have received considerable attention, as they are often found in mass rearings of beneficial arthropods. They affect the efficacy of these predators as biological control agent of insect and mite pests. Microsporidia do not seem to have potential for biological control of mites.     

Driving factors of the communities of phytophagous and predatory mites in a physic nut plantation and spontaneous plants associated

Seasonal changes in climate and plant diversity are known to affect the population dynamics of both pests and natural enemies within agroecosystems. In Brazil, spontaneous plants are usually tolerated in small-scale physic nut plantations over the year, which in turn may mediate interactions between pests and natural enemies within this agroecosystem. Here, we aimed to access the influence of seasonal variation of abiotic (temperature, relative humidity and rainfall) and biotic (diversity of spontaneous plants, overall richness and density of mites) factors on the communities of phytophagous and predatory mites found in a physic nut plantation and its associated spontaneous plants. Mite sampling was monthly conducted in dicotyledonous and monocotyledonous leaves of spontaneous plants as well as in physic nut shrubs over an entire year. In the dry season there was a higher abundance of phytophagous mites (Tenuipalpidae, Tarsonemidae and Tetranychidae) on spontaneous plants than on physic nut shrubs, while predatory mites (Phytoseiidae) showed the opposite pattern. The overall density of mites on spontaneous plants increased with relative humidity and diversity of spontaneous plants. Rainfall was the variable that most influenced the density of mites inhabiting physic nut shrubs. Agroecosystems comprising spontaneous plants associated with crops harbour a rich mite community including species of different trophic levels which potentially benefit natural pest control due to increased diversity and abundance of natural enemies.     

Biology of Allothrombium pulvinum Ewing (Acari: Trombidiidae) in West Mazandran, Iran

Allothrombium pulvinum Ewing is a common natural enemy of aphids and other arthropods in Iran. It is univoltine in Iran. The eggs hatch in spring, nymphs emerge in early summer and adults appear in autumn. Larvae are ectoparasites of aphids whereas deutonymphs and adults are free-living predators of aphids and spider mites. Adults hibernate in the soil and in cracks of tree trunks during winter. When spring comes, females lay eggs in the soil, on the soil surface and on weeds. Phytoseius plumifer (Phytoseiidae) was observed to be phoretic on deutonymphs of A. pulvinum on nettle trees (Celtis australis). In the laboratory, development from the egg to adult stage takes at least 107 days at 25±1°C. Soil is not essential for female oviposition. High humidity is the most important factor for oviposition and development in A. pulvinum.     

Abundance of phytoseiid mites on Vitis species: effects of leaf hairs,domatia, prey abundance and plant phylogeny

We observed the number of predatory mites (Phytoseiidae:Typhlodromus caudiglans) on the foliage of 20 North American species of grapes (Vitis spp) plus the domesticated EuropeanVitis vinifera, all grown in a common garden. We found relatively few phytophagous mites. The numbers of phytophagous mites were not correlated with the plant characteristics that we measured. We found approximately five times as many predatory mites as phytophagous mites and the numbers of these phytoseiid predators were not affected by the availability of prey. Similarly, numbers of phytoseiids were unaffected by plant gender and, hence, the availability of pollen, another source of food. The numbers of phytoseiids were not clustered according to the taxonomic grouping of the tested plant species. Leaf surface characteristics explained over 25% of the variance in the numbers of phytoseiids. Numbers of phytoseiids were positively associated with the density of vein hairs, the density of bristles in leaf axils, and the presence of leaf domatia. These results suggest that sheltered habitats rather than food availability may limit the numbers of phytoseiid mites on grapevines.     

Use of spinosad and predatory mites for the management of Frankliniella occidentalis in low tunnel‐grown strawberry

Frankliniella occidentalis (Pergande) (Thysanoptera: Thripidae) is a major pest of strawberry. The efficacy of three species of predatory mites, Typhlodromips montdorensis (Schicha), Neoseiulus cucumeris (Oudemans) (both: Acari: Phytoseiidae), and Hypoaspis miles (Berlese) (Acari: Laelapidae), and their compatibility with spinosad for the control of this thrips was evaluated in commercial strawberry in spring. Low tunnel‐grown strawberry was treated with ‘water then mites’, ‘spinosad then mites’, or ‘mites then spinosad’. Predatory mites were released as single‐, two‐ and three‐species combinations. Overall, spinosad‐treated plants had fewer thrips than water‐treated plants (control). In all treatment regimes, each species of predatory mite reduced the number of thrips relative to those plants that received no mites. Predatory mites were most effective in reducing thrips when released after spinosad was applied. Any multiple‐species combination of predatory mites reduced thrips numbers more than single‐species releases. The two‐species combination of T. montdorensis (foliage inhabiting) and H. miles (soil dwelling) was the most effective in suppressing thrips. The next most effective combination was a three‐species release. Of multiple‐species combinations, the two‐species combination of T. montdorensis and N. cucumeris was the least effective in suppressing thrips numbers. The spinosad and mites only temporarily reduced the numbers of F. occidentalis. This suggests that further application of predatory mites, spinosad, or both is required to maintain F. occidentalis populations below an economically damaging level.     

Biological control of Pacific mites and Willamette mites in San Joaquin Valley vineyards: part III. Role of tydeid mites

In the absence of spider mites, tydeids (Pronematus anconaiBaker and Pronematus ubiquitus [Mc Gregor ]) may serve as alternate prey to maintain good numbers of the predatory mite, Metaseiulus occidentalis (Nesbitt ) (Acarina, Phytoseiidae), late in the season. This late-season predator and alternate prey relationship is necessary to stabilize Pacific mite populations and perpetuate balance in San Joaquin Valley vineyards. Thriving laboratory colonies of tydeids were reared on a diet of windblown pollens, including cattail pollen (Typha sp., Typhaceae) and bottlebrush pollen (Melaleuca sp., Myrtaceae).M. occidentalis was successfully reared on a diet of tydeids and ovipositing predator females were obtained. In addition, pollen dusted on grapevines significantly increased both tydeid and indirectly M. occidentalis populations late in the season. These studies suggest that artificially disseminating cattail pollen or manipulating good pollen producing flora in and around vineyards may be used to correct situations where Pacific mites have become serious pests.     

Spider-Mite Problems and Control in Taiwan

Problems with spider mites first appeared in Taiwan in 1958, eight years after the importation of synthetic pesticides, and the mites evolved into major pests on many crops during the 1980s. Of the 74 spider mite species recorded from Taiwan 10 are major pests, with Tetranychus kanzawai most important, followed by T. urticae, Panonychus citri, T. cinnabarinus, T. truncatus and Oligonychus litchii. Most crops suffer from more than one species. Spider mites reproduce year-round in Taiwan. Diapause occurs only in high-elevation areas. Precipitation is the most important abiotic factor restricting spider-mite populations. Control is usually accomplished by applying chemicals. Fifty acaricides are currently registered for the control of spider mites. Acaricide resistance is a serious problem, with regional variation in resistance levels. Several phytoseiid mites and a chrysopid predator have been studied for control of spider mites with good effect. Efforts to market these predators should be intensified so that biological control can be a real choice for farmers.     

Species status and population genetic structure of grapevine eriophyoid mites

Bud mite, blister mite (Colomerus vitis Pagenstecher), and rust mite (Calepitrimerus vitis Nalepa) (Acari: Eriophyoidae) are recognized grapevine pests. Much of the biology and ecology of these pests is poorly understood. We used two types of molecular markers to gain further insight into the breeding biology and population structure of these mites, using individuals collected from sites around south‐eastern Australia. Patterns of genetic variation observed using PCR‐RFLP of ITS 1 (Internal Transcribed Spacer 1) confirmed the separate species status of the rust mite, and resolved the species status of bud and blister mites, revealing two closely related but distinct species. Microsatellite markers revealed extensive genetic differentiation between bud mite populations and blister mite populations even at micro‐geographical levels, suggesting low movement in these species. The findings indicate that separate control strategies are needed against bud and blister mites, and that localized control strategies are likely to be effective given their limited dispersal.     

Do domatia mediate mutualistic interactions between coffee plants and predatory mites?

Many plant species possess structures on their leaves that often harbour predatory or fungivorous mites. These so‐called domatia are thought to mediate a mutualistic interaction; the plant gains protection because mites decimate plant pathogenic fungi or herbivores, whereas the mites find shelter in the domatia. We tested this hypothesis using two species of coffee (Coffea spp.) plants that posses domatia consisting of small cavities at the underside of the leaves, and which often harbour mites. We assessed densities of domatia, of the predatory mite Iphiseiodes zuluagai Denmark and Muma (Acari: Phytoseiidae) and of herbivorous mites Oligonychus ilicis (McGregor) (Acari: Tetranychidae) and Brevipalpus phoenicis (Geijskes) (Acari: Tenuipalpidae) on Coffea arabica L. (Rubiaceae) and Coffea canephora Pierre in the field. Over a period of 50 days, C. arabica harboured on average 7.5 times more predatory mites and 0.4–0.66 fewer prey mites than C. canephora. Hence, the higher density of predatory mites on C. arabica could not be explained by higher densities of prey. However, the density of domatia on C. arabica was on average 1.65 times higher than on C. canephora, and within each species, leaves with higher densities of domatia also harboured more predators. This suggests a positive effect of domatia on predatory mites. In the laboratory, survival of adult female predatory mites on leaves of C. arabica with open domatia was indeed significantly higher than on leaves with closed domatia. Hence, predatory mites benefited from the domatia. However, plants with higher densities of domatia did not harbour fewer herbivores. Taken together, our study only provides partial evidence for a mutualistic interaction between coffee plants and predatory mites, mediated by domatia.     

Artificial ground shelters for overwintering phytoseiid mites in orchards

Biological control in orchards strongly depends on winter survival of natural enemies, especially in temperate regions. Predacious phytoseiid mites overwinter on trees or on the ground depending on the characteristics of the species. However, the overwintering ecology of phytoseiid mites on the ground is less well known than that of those on trees. We investigated the usefulness of artificial overwintering shelters as a tool for studying the overwintering ecology of phytoseiid mites on the ground. Four kinds of artificial shelter (shading net, felt, cardboard, and urethane foam) were placed on the ground in an apple orchard in Korea. Two dominant phytoseiid species, Neoseiulus makuwa (Ehara) and N. womersleyi (Schicha) (Acari: Phytoseiidae), overwintered in the artificial ground shelters, and numbers were highest in the urethane foam among the four kinds of shelter, and next highest in the shading net. On the other hand, the numbers of phytoseiid mites collected in the ground vegetation plus soil samples under the ground shelters were not significantly different among the five shelter treatments, including the no-shelter control. Our results suggest that artificial overwintering shelters are efficient tools for investigating overwintering ecology of phytoseiid mites on the ground, as well as on trees, in orchards. Furthermore, the artificial shelters would be good sampling units because they are easily formed into identical sizes and can be used almost anywhere in the field with less laborious work. We also discuss some implications about the effects of sheltered structures on the ground on the populations of phytoseiid mites during winter.     

Mite (Acari; Arachnida) diversity of two native plants in fragments of a semideciduous seasonal forest in Brazil

Studies to determine mite species richness in natural environments are still scarce, and have been conducted mainly in tropical ecosystems. The aim of this study was to determine the species richness of mites on two common native plants in fragments of the semideciduous seasonal forest in the Northwest of São Paulo State, Brazil. In each of eight fragments, 10 specimens of Actinostemon communis (Euphorbiaceae) and 10 of Trichilia casaretti (Meliaceae) were selected and marked. In total, 124 species of mites belonging to 21 families were found on the two plants. Tarsonemidae had the highest diversity (34 species), followed by Phytoseiidae (31), Tetranychidae (9) and Tenuipalpidae (8). Species accumulation curves for the two sampled plants did not reach an asymptote, even with the large sampling effort. Hence, it is estimated that a greater sampling effort may lead to an increase in species richness compared with what was found in this study. The richness of this mite fauna suggests that preservation of these plant species is important to maintain the mite diversity in these forest fragments.     

Avian pest control in tea plantations of sub-Himalayan plains of Northeast India: Mixed-species foraging flock matters

This study reports on the biocontrol role birds play in caterpillar pest control of tea plantations of Northeast India. In this area large tracts of tea plantations have been extensively defoliated by the recent invasion of two forest-dwelling geometrid looper caterpillars, Hyposidra spp. and a lymantriid hairy caterpillar, Arctornis submarginata. This exacerbated tea herbivory by two resident pest caterpillars, Biston suppressaria and Eterusia magnifera. Currently there are no identified resident insect predators for any life stage of Hyposidra spp. and A. submarginata. Larvae of these pests drop from tea bushes using salivary thread, allowing caterpillars to escape from insect predators. The study identified 38 native insectivorous bird species in tea plantations, of which four species (Asian-pied starling, Chestnut-tailed starling, Jungle Myna, Red-vented Bulbul) could be potential control agents of looper and hairy caterpillar pests. These species had high population densities. Their cumulative abundances represented a major proportion of the total bird community during both the infested (86.44%) and non-infested phase (75.34%). They foraged in mixed-species flocks in both tea foliage and on the ground. This behavior is suited to capture foliage-living and dropped caterpillars that were flushed from tea bushes by foraging birds. Abundance and species richness of overall tea layer-foraging birds were higher in infested phase when compared to non-infested phase. The predation rate of four bird species of the foraging flock varied significantly. These results suggest that birds should be considered as important biological control agent of caterpillar pests of tea and considered in pest management plans.     

A study about geographical distribution of root lesion nematode (Pratylenchus loosi, Loof 1960) in tea gardens at Guilan Province, Iran

Root lesion nematode of tea (Pratylenchus loosi) is one of the most dangerous and distractive pests in all over areas in the world where tea grows. In Iran, this species was one of the quarantine pests that for first time it were separated from the Japan imported tea slips and reported by Maafi (1993). Nowadays it has been distributed in some tea growth areas of Guilan and Mazandaran provinces (North of Iran). In this study, geographical distribution of this pest is reported on some tea growth areas of Guilan province. In order to, 147 samples from root and soil around them were investigated. These samples were gathered from various gardens of Guilan province. They were transferred to nematology lab with suitable temperature and moisture conditions and were stored at 5-10 degrees C until extraction time. Centrifugal methods for nematode extraction from soil (Jenkins, 1964) and from root (Coolen & D'Herde, 1972) were used. The nematode was identified by Handoo & Golden (1989) and Frederick & Tarjan (1989) diagnostic keys. According to this study different infested areas and geographical distribution were detected in Guilan province. Results indicated that many important tea growth areas in Guilan were infested by this nematode. In addition, it seems that it has been distributed during short time.