稻田微蛛周年性活动研究

本文记述了稻田微蛛种群的周年性变动状况。根据我们在湘阴县调查:稻田微蛛有四属四种,优势种为食虫瘤胸蛛,其发生量占微蛛总量的73%。稻田微蛛种群数量的变化有一定规律性,全年有三个起伏,3、7与11月上升,5月的夏收夏种与8月的秋收秋种时期下降。早稻田间发生量占总蛛量的41.82%,是主要捕食性天敌,晚稻期间发生量少,作用较小。各生境微蛛种群组合基本相似,但各种群大小及优势种不同。微蛛在稻田的水平与垂直分布,耐饥与耐旱能力亦作了考察与测定。

A RESEARCH ON ANNIVERSARY ACTIVITY OF MICRO-SPIDERS(ERIGONIDAE)IN RICE FIELDS

Micro-spiders are very rich in the natural resources in rice fields.Accordingto collection and identification of micro-spiders speciment in Xingyin county,there are four species of spiders representing four genus.They make up 41.82%of the total number of the spiders in early rice fields.The dominant species isOedothorax insecticeps that make up 73% of total number of the microspiders inthe fields.It has been noted that the micro-spiders species are quite same throughoutthe seasons,but relative quantity of micro-spiders species changes from time totime in different niche.The dominant species is Oedothorax insecticeps in ricefields and bank,but it is Erigone graminicolum on the citrus and forests.The present paper shows the changing-law in the population density of micro-spiders in the fields.There were three density fluctuation of total number ofmicro-spiders throughout the year in the fields,with rising occurred in March,July,and November,falling occurred in May-Summer harvesting and planting,and August-Autumn harvesting and sowing.Micro-spiders are a important naturalenemies occupying 38.46% of the total number of all predatous in early ricefields,but there are not important occupying only 6.15% of the total number ofall predatous in late rice fields.Horizontal distribution of micro-spiders is well-distributed in rice fields,butventical distribution is of an aggregation pattern,which distribution between1-16cm of rice.The functional response of Oedothorax insecticeps to prey increased with theincrease of prey density,and decreased with the increase of its own density.The ability of drought-enduring of micro-spiders is stronger than hunger-endur-ing ability,and hunger-enduring of Erigone greminicolum is stronger than thatof Oedothorax inseticeps.