Occurrence and fluctuation of mite populations associated with rubber tree crop neighbor of fragments of cerrado

The basic knowledge of the seasonal occurrence of mites can supply data for elaboration of programs of ecological management to be implanted with success in the future. The objective of this study was to determine the species richness and the seasonality of mites present in two areas of rubber tree crops neighboring to native areas in Itiquira, MT. Along one year, 25 quantitative samplings were accomplished in rubber tree crop neighboring to two fragments of Cerrado (Cerrad?o and Mata Ripária). There were registered 199,380 mites, of 48 species, belonging to 15 families. Of those, 13 species are phytophagous, 18 predators and 17 mycophagous or of unknown alimentary habit. Three phytophagous species represented more than 97% of the mites collected: Phyllocoptruta seringueirae Feres (80.8%), Tenuipalpus heveae Baker (12.7%) and Calacarus heveae Feres (3.6%). Among the predators, the most abundant species were Agistemus sp., Scirula sp. and Euseius concordis (Chant). Twenty-eight species were common to both crops. The families that had the largest number of species collected in the neighboring area to Cerrad?o were Tydeidae (7), Tarsonemidae (6), Eriophyidae and Phytoseiidae (4), and in the area close to Mata Ripária, Tydeidae (9) and Phytoseiidae (8). The presence of vegetation near the crop should explain the great number of species of mites classified as accidental found in this study. The largest abundances and species richness occurred in the end of the rainy season and beginning of the dry season.     

Vegetation increases the abundance of natural enemies in vineyards

Non-crop areas can increase the abundance of natural invertebrate enemies on farmland and assist in invertebrate pest control, but the relative benefits of different types of vegetation are often unclear. Here, we investigated abundance of natural enemies in vineyards with edges consisting of different types of vegetation: remnant native forests, wooded margins planted after establishment of the crop (hereafter called shelterbelts), or pasture. Invertebrates were sampled four times using canopy sticky traps and ground level pitfall traps, replicated across two seasons at one of the sites. The distribution and abundance of natural enemies in relation to edges with adjacent vegetation or pasture were mapped by distance indices (SADIE) and compared with ANOVAs. There was a positive influence of adjacent wooded vegetation on staphylinids, predatory thrips, predatory mites, spiders, ladybird beetles and hymenopteran parasitoids including Trichogramma egg parasitoids in the canopy and/or at ground level, although there were significant differences among sites and groups of organisms. In contrast, pasture edges had no effect or a negative effect on numbers of natural enemies in vineyards. To directly assess potential beneficial effects of adjacent vegetation, predation and parasitism of eggs of a vineyard insect pest, Epiphyas postvittana Walker (Lepidoptera: Tortricidae), was measured. Parasitism by Trichogramma was higher adjacent to remnant vegetation while predation was not affected. These results indicate that the abundance and distribution of vineyard natural enemies and parasitism of pest moth eggs is increased adjacent to edges with wooded vegetation, leading to beneficial effects for pest control. The conservation of remnant woodland and planting of shelterbelts around vineyards may therefore have direct economic benefits in terms of pest control, whereas non-crop pasture may not produce such benefits.     

Mites (Acari) from rubber trees (Hevea brasiliensis Muell. Arg., Euphorbiaceae) and spontaneous euphorbiaceous in rubber trees cultivation

Quarterly samples were done in 2001 on three rubber tree plantation in the northwest of the state of S?o Paulo. Three rubber trees of each locality were sampled. Between the rows of rubber tree four species of spontaneous euphorbiaceous were collected: Chamaesyce hirta, C. hyssopifolia, Euphorbia heterophylla and Phyllanthus tenellus. A total of 8.954 mites of 38 species, belonging to 31 genera of 11 families were collected. Tydeidae and Phytoseiidae had the highest diversity of species, 9 and 7, respectively. The most abundant families were Eriophyidae (3.594), Tydeidae (2.825) and Tenuipalpidae (1.027). The most abundant species on the rubber trees were: phytophagous - Calacarus heveae Feres, Tenuipalpus heveae Baker, Lorryia sp.2, Lorryia formosa Cooreman and Lorryia sp.1; predators - Zetzellia quasagistemas Hernandes & Feres, Pronematus sp., Iphiseiodes zuluagai Denmark & Muma and Euseius citrifolius Denmark & Muma. Among the spontaneous euphorbiaceous, predatory mites were abundantly found on C. hirta and E. heterophylla, mainly Pronematus sp. and E. citrifolius, suggesting that these plants could be important in the maintenance of these predators in the rubber tree cultivation areas. However, plants that can shelter predators and at the same time exert strong competition (nutrients, water etc) to rubber trees, can not be recommended for pest management programs. Studies about competition between rubber trees and spontaneous plants need to be conducted for feasible efficient programs of environmental management, aiming at the control of pest mites of rubber tree.     

Keystone resources available to wild pollinators in a winter‐flowering tree crop plantation

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Edges in Agricultural Landscapes: Species Interactions and Movement of Natural Enemies

Agricultural landscapes can be characterized as a mosaic of habitat patches interspersed with hostile matrix, or as a gradient of patches ranging from suitable to unsuitable for different species. Arthropods moving through these landscapes encounter a range of edges, with different permeability. Patches of native vegetation in these landscapes may support natural enemies of crop pests by providing alternate hosts for parasitic wasps and/or acting as a source for predatory insects. We test this by quantifying species interactions and measuring movement across different edge-types. A high diversity of parasitoid species used hosts in the native vegetation patches, however we recorded few instances of the same parasitoid species using hosts in both the native vegetation and the crop (canola). However, we did find overall greater densities of parasitoids moving from native vegetation into the crop. Of the parasitoid groups examined, parasitoids of aphids (Braconidae: Aphidiinae) frequently moved from native vegetation into canola. In contrast, parasitoids of caterpillars (Braconidae: Microgastrinae) moved commonly from cereal fields into canola. Late season samples showed both aphids and parasitoids moving frequently out of native vegetation, in contrast predators moved less commonly from native vegetation (across the whole season). The season-long net advantage or disadvantage of native vegetation for pest control services is therefore difficult to evaluate. It appears that the different edge-types alter movement patterns of natural enemies more so than herbivorous pest species, and this may impact pest control services.     

Phytoseiidae mites associated with Hevea spp. from the Amazon region: a hidden diversity under the canopy of native trees

Despite the Amazon Forest being the largest tropical forest in the world, and cradle of rubber trees (Hevea brasiliensis), no studies have aimed to report the occurrence of mites associated with native trees from this ecosystem. Our survey investigates the phytoseiid mites associated with five species of native rubber trees from nine sites of the Amazon Forest, and also presents a major review of phytoseiid species from natural vegetation in Brazil. We found a total of 1305 mites, belonging to 30 species, of which seven were new to science, Amblydromalus akiri sp. nov., Amblyseius chicomendesi sp. nov., Amblyseius duckei sp. nov., Amblyseius manauara sp. nov., Iphiseiodes katukina sp. nov., Iphiseiodes raucuara sp. nov. and Typhlodromips igapo sp. nov.; beyond two new records for Brazil, Iphiseiodes kamahorae and Amblyseius martus. Our results emphasize the importance of Amazon native trees as an unexplored source of predator mites, which in turn may be further studied as biological control agents of pest mites on rubber trees. The impressive diversity, endemism and rate of new species found highlight the importance of studies on arthropod communities associated with the Amazon vegetation.     

北京地区火炬树的萌蘖繁殖扩散

首次通过调查火炬树单株和火炬树林分的萌蘖繁殖扩散状况和小样方方法调查火炬树林下的乔木树种天然更新,了解火炬树对北京主要植被类型:油松人工林、侧柏人工林、刺槐人工林和灌木丛的扩散入侵情况。调查发现:在北京荒山爆破造林示范区,火炬树单株8a来4 5°扇形单方向扩散的最远距离为8.35 m,扩散萌蘖的最多株数达98株。立地条件差,特别是土层薄,裸露的岩石多是影响火炬树扩散能力的主要因素,但没有对火炬树萌蘖株的生长产生重要影响。扩散的群体中地径以小径阶个体占主体,说明火炬树萌蘖能力旺盛。在已有高大乔木的立地,如侧柏人工林和油松人工林,火炬树虽然能扩散进入,但只是伴生下木,很难形成优势群体;乔木林内光照明显影响火炬树的扩散数量和扩散规律;并且发现有10种北京当地乔木树种能在火炬树林下天然下种更新并且正常生长。分析表明火炬树没有对北京当地乔木群落构成威胁。火炬树能扩散进入邻近的灌木丛,并且扩散进入灌木丛的火炬树明显比扩散进乔木林内的火炬树长得高。火炬树的生物学和生态学特性决定了它是良好的荒山造林的先锋树种,不可能成为顶极群落的优势树种。所以火炬树目前对北京山区自然、半自然森林生态系统没有产生入侵危害。     

Ecosystem Services and Biodiversity in a Rapidly Transforming Landscape in Northern Borneo

Because industrial agriculture keeps expanding in Southeast Asia at the expense of natural forests and traditional swidden systems, comparing biodiversity and ecosystem services in the traditional forest–swidden agriculture system vs. monocultures is needed to guide decision making on land-use planning. Focusing on tree diversity, soil erosion control, and climate change mitigation through carbon storage, we surveyed vegetation and monitored soil loss in various land-use areas in a northern Bornean agricultural landscape shaped by swidden agriculture, rubber tapping, and logging, where various levels and types of disturbance have created a fine mosaic of vegetation from food crop fields to natural forest. Tree species diversity and ecosystem service production were highest in natural forests. Logged-over forests produced services similar to those of natural forests. Land uses related to the swidden agriculture system largely outperformed oil palm or rubber monocultures in terms of tree species diversity and service production. Natural and logged-over forests should be maintained or managed as integral parts of the swidden system, and landscape multifunctionality should be sustained. Because natural forests host a unique diversity of trees and produce high levels of ecosystem services, targeting carbon stock protection, e.g. through financial mechanisms such as Reducing Emissions from Deforestation and Forest Degradation (REDD+), will synergistically provide benefits for biodiversity and a wide range of other services. However, the way such mechanisms could benefit communities must be carefully evaluated to counter the high opportunity cost of conversion to monocultures that might generate greater income, but would be detrimental to the production of multiple ecosystem services.     

Distribution and effects of tree leaf litter on vegetation composition and biomass in a forest-grassland ecotone

Aims After abandonment of grasslands, secondary succession leads to the invasion by woody species. This process begins with the accumulation of tree litter in the forest–grassland ecotone. Our objectives were to determine the relationships between litter amounts and vegetation composition and cover along natural forest–grassland ecotones and to experimentally study the initial effects of tree litter accumulation on grassland vegetation and on microsite conditions.Methods We established 11 transects varying from 12 to 15 m in length in different forest–grassland ecotones in the Lahn-Dill highlands, Germany, and measured the mass and cover of tree litter and the cover and composition of vegetation at five sequential positions along each transect by using 1 m 2 plots with five replications. In a field experiment, we established plots subjected to different litter amounts (0, 200 and 600g m ?2) and evaluated changes in grassland vegetation, soil temperature and soil nutrient availability below the litter layer.Important findings Tree litter amounts decrease from 650 to 65g m ?2 across the forest–grassland ecotone. Vegetation changed from shrubs and annual species (adapted to more stressful conditions) in the forests edge to grasses, rosettes and hemirosette species (with higher competitive abilities) in the grassland. These anthropogenic forest–grassland ecotones showed abrupt edges, and the two adjacent ecosystems were characterized by different species pools and functional groups. In the field experiment, the presence of a litter layer reduced vegetation biomass and cover; the species richness was only reduced in the treatment with high litter (600g m ?2). Additionally, adding litter on top of vegetation also reduced thermal amplitude and the number of frost days, while increasing the availability of some nutrients, such as nitrogen and aluminium, the latter being an indicator of soil acidification. Adding a tree litter layer of 600g m ?2 in grassland areas had strong effects on the composition and diversity of grassland vegetation by reducing the cover of several key grassland species. In, or near, forest edges, litter accumulation rapidly changes established vegetation, microsite conditions and soil nutrients.     

Impact of warming and timing of snow melt on soil microarthropod assemblages associated with Dryas-dominated plant communities on Svalbard

Open Top Chambers (OTCs) were used to measure impacts of predicted global warming on the structure of the invertebrate community of a Dryas octopetala heath in West Spitsbergen. Results from the OTC experiment were compared with natural variation in invertebrate community structure along a snowmelt transect through similar vegetation up the adjacent hillside. Changes along this transect represent the natural response of the invertebrate community to progressively longer and potentially warmer and drier growing seasons. Using MANOVA, ANOVA, Linear Discriminant Analysis and χ² tests, significant differences in community composition were found between OTCs and controls and among stations along the transect. Numbers of cryptostigmatic and predatory mites tended to be higher in the warmer OTC treatment but numbers of the aphid Acyrthosiphon svalbardicum , hymenopterous parasitoids, Symphyta larvae, and weevils were higher in control plots. Most Collembola, including Hypogastrura tullbergi , Lepidocyrtus lignorum and Isotoma anglicana , followed a similar trend to the aphid, but Folsomia bisetosa was more abundant in the OTC treatment. Trends along the transect showed clear parallels with the OTC experiment. However, mite species, particularly Diapterobates notatus , tended to increase in numbers under warming, with several species collectively increasing at the earlier exposed transect stations. Overall, the results suggest that the composition and structure of Arctic invertebrate communities associated with Dryas will change significantly under global warming.     

Diversity and abundance of arthropods in subtropical rice growing areas in the Brazilian south

This paper describes a survey of arthropods in rice-growing areas of Rio Grande do Sul, Brazil, undertaken to identify the main groups of insect pests and their natural enemies present in three producing regions during the stages of crop development. The study was conducted during the crop years 2007/2008 and 2008/2009 in the municipalities of Cachoeira do Sul, Eldorado do Sul and Capivari do Sul. A total of 44,231 arthropods were collected: 26,821 in 2007/2008 and 17,410 in 2008/2009. Spatial and temporal patterns were analyzed utilizing the 28 principal families and applying the Morisita–Horn coefficient and the Detrended Correspondence Analysis (DCA). Both results demonstrated variances of abundance and richness from 1 year to the next in the evaluated areas. The results indicate that the arthropod communities in southern Brazilian rice crop agro-ecosystems are formed of a few families with high abundance and a large number of other smaller families. Among the phytophagous arthropods found, Pentatomidae, Orthoptera and planthoppers were predominant while the natural enemies were mainly predatory mites, spiders, Hymenoptera and Odonata. This study demonstrates that irrigated rice fields located in subtropical areas of the Brazilian South sustain a great variety of arthropods which facilitate studies on bio-diversity conservation and the development of sustainable management of the pests.     

The role of native vegetation on infection rates of Calacarus heveae (Acari: Eriophyidae) by Hirsutella thompsonii (Ascomycota: Ophiocordycipitaceae)

Hirsutella thompsonii (Fischer) (Ascomycota: Ophiocordycipitaceae), a fungal pathogen, often causes high mortality in populations of Calacarus heveae Feres (Acari: Eriophyidae), an important pest mite in rubber tree plantations (Hevea brasiliensis Muell. Arg., Euphorbiaceae). However, the ecological and climatic factors regulating this host-pathogen system are poorly known. We compared fungal infections in agroforestry and traditional rubber plantations to evaluate the role of native vegetation and climatic factors on infection rates of C. heveae by H. thompsonii. While the prevalence of H. thompsonii was higher in managed rubber tree plantations, the abundance of C. heveae was about three times higher in traditional plantations. Abundance of C. heveae, agroecosystem management type and microclimatic variables were responsible for driving the infection rates of H. thompsonii. Native vegetation was a source for H. thompsonii and also modified the crop’s microclimate, which contributed to its maintenance in the crop fields. Therefore, appropriate management practices may enhance the effects of entomopathogens on conservative biological control of pest mites in agroforestry systems.     

Contrasting structures of plant–mite networks compounded by phytophagous and predatory mite species

Differences in the feeding habits between phytophagous and predatory species can determine distinct ecological interactions between mites and their host plants. Herein, plant–mite networks were constructed using available literature on plant-dwelling mites from Brazilian natural vegetation in order to contrast phytophagous and predatory mite networks. The structural patterns of plant–mite networks were described through network specialization (connectance) and modularity. A total of 187 mite species, 65 host plant species and 646 interactions were recorded in 14 plant–mite networks. Phytophagous networks included 96 mite species, 61 host plants and 277 interactions, whereas predatory networks contained 91 mite species, 54 host plants and 369 interactions. No differences in the species richness of mites and host plants were observed between phytophagous and predatory networks. However, plant–mite networks composed of phytophagous mites showed lower connectance and higher modularity when compared to the predatory mite networks. The present results corroborate the hypothesis that trophic networks are more specialized than commensalistic networks, given that the phytophagous species must deal with plant defenses, in contrast to predatory mites which only inhabit and forage for resources on plants.     

捕食螨化学生态研究进展

捕食螨是重要的生物防治因子。早在20世纪70年代就发现了捕食螨的性信息素,许多研究证明植物挥发物在捕食螨向猎物定位过程中发挥着至关重要的作用,影响捕食螨寻找猎物的植物挥发物来源于未受害植物、机械损伤植物、猎物危害植物、非猎物危害植物。人工合成的植物挥发物组分对捕食螨具有引诱作用,但引诱活性低于虫害诱导植物释放的挥发性混合物。捕食螨的饲养条件、饥饿程度、学习与经验行为等会影响捕食螨对植物挥发物的反应。介绍了信息素与植物挥发物对捕食螨的作用,并讨论了目前存在的问题和研究前景。     

完达山林区森林采伐和非采伐区马鹿、狍子对冬季生境因子选择的比较

2003—2005年的冬季,在黑龙江省完达山地区的五泡林场,通过样线调查,利用逐步判别分析的方法,对冬季马鹿和狍子在森林采伐区和非采伐区生境选择的差异进行了比较研究,其结果表明,在该地区虽然两物种在生境选择上发生部分重叠,但在生境利用方式上均存在显著差异在采伐区马鹿主要利用中坡位或上坡位、半阴半阳或阳坡、人为干扰距离大于1000m、海拔相对较高、食物丰富度较高、乔木胸径较小、灌木密度较高的灌丛或杂木林生境;狍子主要利用中坡位或下坡位、阳坡、海拔相对较低、食物丰富度适中、乔木胸径较大、灌木密度较低、人为干扰距离要求不严格的杂木林或柞树林生境。在非采伐区,马鹿主要选择距人为干扰大于1000m、海拔较高、食物丰富度较高、乔木胸径较小的杂木林生境;狍子主要选择中坡位或下坡位、人为干扰距离要求不严格、海拔较低、食物丰富度较适中和乔木胸径较大的杂木林或杨-桦混交林生境。     

Mite diversity on plants of different families found in the Brazilian Atlantic Forest

This work reports the occurrence of mites predominantly predatory, phytophagous and with varied feeding habits on plants of the Atlantic Forest vegetation type of the State of S?o Paulo. The objective was to estimate the possible role of the Atlantic Forest vegetation as reservoir of these groups of mites which are also found on plants of agricultural importance. Samples were taken from 187 plant species belonging to 73 families in three vegetation types of the Atlantic Forest from February of 2001 to October of 2002. A total of 2,887 mites belonging to 163 morpho-species of 16 families were collected. Mite diversity was high, especially of predatory mites; these corresponded to 1,562 specimens of 92 morpho-species. Within this group, Phytoseiidae comprised 71% of the specimens and 62% of the morpho-species. Phytophagous mites comprised 836 specimens of 36 morpho-species. Within this group, Tenuipalpidae comprised the larger proportion of specimens (61%) whereas Tetranychidae corresponded to the larger proportion of morpho-species (64%). Mites with varied feeding habits corresponded to 491 specimens of 36 morpho-species. In this group, the larger proportion of specimens (52%) consisted of Ascidae and the larger proportion of morpho-species (42%) consisted of Tydeinae (family Tydeidae). High abundance and high morpho-species richness of mites of predominantly predatory, phytophagous and variable feeding habits were observed on 17, five and nine plant species, respectively. The results obtained suggest the importance of plants of the studied vegetation as reservoirs of predatory mites.     

半自然农田边界与相邻农田步甲和蜘蛛的时空分布

分别于小麦、玉米收获前后,采用陷阱法调查了华北地区典型农业景观中具有不同植被结构的农田边界及其相邻农田中两类重要天敌类群步甲和蜘蛛的多样性.通过比较农田生境及相邻农田边界间两类天敌群落的时空分布格局及其与相邻半自然生境植被群落的相关关系,探讨半自然农田边界对两类天敌类群的保护作用.结果表明: 整个取样季节农田边界处蜘蛛的多度显著高于农田内部;而步甲多样性在农田与边界间无显著性差异,仅呈现不同的群落结构;作物收获后蜘蛛分科数在边界处的增加以及在农田的减少,显示了蜘蛛在农田和边界之间的迁移活动.边界植被结构对蜘蛛和步甲多样性有不同影响:边界较高的草本层盖度和较低的乔木层盖度有利于增加农田中某些步甲优势种的多样性;而较高的草本层盖度有利于增加皿蛛科蜘蛛的多样性.因此,半自然生境的存在可以通过天敌在农田和边界之间的迁移运动促进农田天敌多样性的维持;但不同类型半自然生境植被群落结构可能影响其对不同天敌群落多样性的维持和保护作用.为促进农业景观对天敌的保护作用,提高其害虫控制功能,需要深入了解不同天敌的生境需求及食物需求,精心设计有利于天敌多样性维持的半自然生境.     

Mites (Acari) associated to Myrtaceae in areas of Cerrado in the State of São Paulo with faunistic analysis of families Tarsonemidae and Phytoseiidae

The objective of this study was to determine and to analyse the diversity of mites on native Myrtaceae of the "Cerrado" vegetation type of the State of S?o Paulo, with particular attention to the families Phytoseiidae and Tarsonemidae. In the year 2000, mites were collected from Myrtaceae species in three "Cerrado" areas in the State of S?o Paulo. Samples of leaves, flowers and fruits were taken from three plant of each species in each site. Mites of 49 genera belonging to 14 families were found. Fourteen phytoseiid species of nine genera and 19 tarsonemid species of six genera were collected. The most abundant phytoseiids were Euseius citrifolius Denmark & Muma, Transeius bellottii (Moraes & Mesa) and Amblyseius acalyphus Denmark & Muma. The most abundant tarsonemids were Daidalotarsonemus tesselatus DeLeon, Daidalotarsonemus folisetae Lofego & Ochoa and Metatarsonemus megasolenidii Lofego & Ochoa. The highest indexes of diversity of phytoseiids and tarsonemids were observed in the fall; the lowest indexes were found in the winter for phytoseiids and in the spring for tarsonemids. Taking into consideration the total number of phytoseiids and tarsonemids collected in this work, the corresponding indexes of diversity (Shannon) were similar and close to 2.0. Different predatory mite species prevailed on distinct plant species, indicating the complementariness of the latter as reservoirs of the former.     

Colonization of Languedoc vineyards by phytoseiid mites (Acari: Phytoseiidae): influence of wind and crop environment

A natural increase of phytoseiid mite populations (Kampimodromus aberrans, Typhlodromus pyri and Phytoseius plumifer) was observed in vineyards in Languedoc, Burgundy and Corsica under integrated pest management strategies. The aim of the present study was to characterize the mechanisms of this colonization in space and time in Languedoc. The abundance of phytoseiid mites in the vegetation close to three grape fields was determined twice a year (May and July). Aerial (funnels with water) and soil (felt strip) traps were placed in and around grape fields, in order to assess the colonization potential provided by aerial dispersal and ambulatory locomotion. The populations of phytoseiid mites in the crops were studied twice a month in order to gain information on the make up of the dispersal populations. The species K. aberrans was found in largest quantities in the traps, in the natural vegetation and in the crops. Predatory mite dispersal occurred essentially by aerial dispersal and was dependent on the wind intensity and wind direction. Identical sex ratios were observed in migrant populations and in populations present in the grape fields, woody areas and hedges. A large proportion of immatures was found to move by aerial dispersal. The colonization potential (rapidity, intensity and regularity) was directly associated with the abundance of the phytoseiids and the proximity of natural vegetation. A deep, dense and tall woody area containing suitable host plants for predatory mites constituted the most stable source of phytoseiid mites. Natural colonization of vineyards provides considerable phytoseiid mite potential that could be managed in an agricultural landscape.