Studies On Dynamics Of Main Wandering Spiders Families In Agroforestry System

Spiders, which were the important group of natural enemies, had more species and number than other predators, and they played an important roll in controlling pests. Based on the current condition of farmland, cultivation management, landscape variation after cultivation and system of forest belt-spiders-farmland, the study is mainly on transfer and temporal variation of dominant species of spiders in different habitats of crops and surroundings, and influence of fanning to the distribution of spiders. The result showed that:1 Forest belt and ridge of field, which were the main habitats of spiders before cultivation and after harvestry, were important species pools of spiders: transform pools during the crop growth and refuges when farming.2 Original evading speed of Lycosa sinensis Schenkel was 26±17.5 cm/s, and farthest jumping distance is 12cm, farthest evading distance is 13.1±0.444 m. There are 10 percent of spiders evading in the cave in the field..3 The influence to spiders differed between the three types of farming: spring ploughing and discharging pesticide had a negative effect on the spiders, weeding had inapparent effect on the spiders.4 Diversity of spiders had negative correlation with distance away from the forest belt, and the difference is most remarkable in an extent(P=0.001, α=0.05), the influence extent in the study was about 20-30 m.5 Temperature and humidity were important factors to the spiders. Habitats affected indirectly by changing the temperature and humidity of microenvironment. Spiders density increased along with increase of temperature and humidity. Spiders density in the fields of tall crop began to decline when reaching the threshold value(31°C, 50%-60%, in the study), and spiders density in the field of large frondage crop still raised. There was no remarkable effect of illumination on spider, but it could influence spiders by changing temperature and humidity.6 Demographic variation of spiders was educed by clustering method. The clustering results reflected the complexity of temporal variation of spider population.7 The result also showed that spiders had strong inclination in habitat selection for surviving-in-winter. They were inclined to the habitat of heterogeneity such as forest belt with complex habitat, ridge of field, the site which was 50m away from the forest belt and so on. The non-cover habitat had a low population of spiders.