| [Purpose] Prairie pests is one kind of major pest groups which are harmful for natural grasslands and pastures, threatening the ecological construction achievements, causing heavy economic losses. This paper aims to clear Ningxia grassland plants, pests and natural enemies community relationship, to explore environmental adaptability grassland predators and pests, the main pests of grassland in Ningxia disaster laws, and grasslands pest control level to lay the foundation.[Research methods]In this study, three main research areas, the indoor cultivation and field surveys carried out a combination of laws grassland in Ningxia main insect pests; comprehensive utilization of GIS technology, RS technology should students carry out research area and distribution division; the use of GPS systems and explore survey establishment of suitable grassland in Ningxia pest monitoring and early warning technology features.Ningxia steppe main pests Occurrence research area is determined as the current Ningxia locust most serious Salt Lake County Mahuangshan typical steppe area, select three survey sample area, since every year in late April to October, every 15 to 20 days to conduct a systematic monitoring. Monitoring methodologies visual method, combined with sweep nets investigation. Survey used random sampling method five points, each point of the statistical survey was repeated 5 times per square ground, mixed locust Population Survey vegetation; each survey point 30 complex network survey, record locust species, quantity, and other state insect, and calculate the locust population density. Indoor development threshold, duration and other studies with a diameter of 13 cm, height 25 cm small and shrouded with artificial climate chamber, set a different light, humidity, temperature gradient and cultured, recording a state insect development, death.Division research should Health District, this study, according Ningxia desert steppe, steppe desert, typical steppe, meadow steppe four major grassland types division, using GPS positioning set of samples, since each year in late April to the end of September, once every 30 d system monitoring, carried out a total of 10 systematic investigation; on the basis of a systematic investigation based on the choice of terrain, aboveground biomass, grassland type, soil type, the average annual rainfall, the annual average temperature of eight major ecological factors, the establishment of grassland pests should be born index evaluation system; the use of ERDAS IMAGINE software Modeler module, enter the relevant factor model to calculate students should factor; select aboveground biomass, grassland type, soil type three major ecological factors, the establishment of grassland pests should Seng index evaluation system.Monitoring of early warning technology, combining the characteristics of the study grassland in Ningxia locust distribution and a total of four different types of grassland setting observation sample 43. All samples were observation using a global positioning system to determine the latitude and longitude coordinates. 5 consecutive years to carry out pest prairie Census(mainly grassland locusts), time of the census in late mid-August of each year. The census process various types of locust samples were collected and made to become specimens, while the vegetation types were investigated record; survey also collected environmental data including dynamic soil moisture, soil temperature, soil nutrients and soil type and other data, in addition to select collection vegetation coverage, height, frequency, density, biomass plants and vegetation diversity, dominance of grasses and other vegetation data 11; data by locusts, predators, in three areas to carry out vegetation species abundance index, Shannon-Wiener seven kinds of indicators to study the relationship between diversity index, a clear monitoring and warning parameters can be used to characterize the locust population.[Results]This study investigated the situation, Mahuangshan locust populations wintering hatch is not neat, each subgroup incubation time varies. The main order of insects succession Pei short nose Locust, Aedes Chorthippus first, followed by red Angaracris locust, Asian car locust, the latest star is a short-winged locust Aedes young locust eggs hatch in mid-May the situation presented(in summer locust) and mid(autumn locust) August bimodal feature; it belongs to the individual’s long thatched significant preference for feeding, and 3 instar larvae daily food consumption(dry, fresh), approximate digestibility significantly different; white streaks Chorthippus system development needs at a higher temperature(nymph 13 ℃, adults 18 ℃) carried out under various developmental age as the temperature rises quickly. Short-winged locust star widely distributed in Ningxia grassland, the most serious of the steppe occurred, appeared in mid-June, the end of August spawning and overwintering eggs; Altai eating dog wow flower and other types of plants, with a clear sexual drive, food consumption, approximate digestion there are also significant differences; short-winged locust star system development needs and Aedes Chorthippus similar, but the high temperature will extend preoviposition. Population of Artemisia Aurea year there are two main peak periods(July peak adults, larvae October peak), the end of October to mature larvae overwinter; individuals of the population in the range of 13 ℃ to 33 ℃ with the development of various ages the temperature rises accelerated above 33 ℃ except eggs outside, each instar larvae were significantly slowed down.Regionalization show: Ningxia natural grassland locust Yisheng area 686.5 hectares, of which: very suitable for locust area 501.1 acres; suitable locust area of 154 acres; more appropriate locust area of 31.4 hectares. The main distribution area of the Helan Mountains along the desert and semi-desert grassland grasshoppers; Shapotou area, in the County of desert grassland grasshoppers; Yanchi County, Tongxin County, Yuanzhou District, Pengyang typical steppe grasshoppers.Grassland monitoring and early warning studies have shown that in the four different types of grassland, with different indicator species and there is no indication indicator species there are higher values. Slope on locust species diversity and population density have obvious negative effects: slope, the lower the locust species diversity, the lower population density. Predators no obvious trend for a particular host plant, which is different herbivorous insects and grasshoppers.[Conclusion]Basic biology, ecology research for individuals to understand and master the harmful biological and ecological evolution of great significance, individual habits, temperature and humidity parameters, and other food consumption through the relationship with the environment, in the form of relationship with the host, and to show the relationship between predators, and to some extent determines the ecological relationship to environmental changes after. Ecological factors in both the abiotic factors and biological factors. Abiotic factors in hydrothermal conditions, topography, soil conditions, determines the spatial distribution characteristics of plant distribution. By plants and animals have a certain consistency in the community distribution, indirectly determines the distribution of animals. Pest monitoring and early warning can use GIS and other technical support, dynamic control of the spatial distribution of biological(size, quantity), with the distribution of ecological factors deduce the spatial distribution of some biological factors at different spatial scales is a comprehensive reflection.On Ningxia typical grassland type, surface predators there is a close relationship between the sub-communities and sub-communities grasshopper. Complete grassland insect communities can maintain sufficient biodiversity, various functional groups can play a dynamic balance of mutual restraint function, which can play the role of natural enemies to control of locust populations, and can effectively prevent predators following effect limited grasshopper population on. Maintenance and protection of species diversity, especially on conservation of natural enemies, such as the prairie grassland ecosystems pests such as locusts control has a positive meaning. In carrying out prevention and control must follow the principle of the conservation of biological diversity in its work, and attention to the use of natural enemies of pests prairie effective control. |
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