栽培牧草地蜘蛛种群动态的研究

A STUDY ON THE SPIDERS POPULATION DYNAMIC IN A FORAGE CROP FIELD

1981—1986年在甘肃武威地区栽培牧草地采集蜘蛛隶属13科58种,分布数量较多的有7种。蜘蛛占草地捕食性天敌总量的71.32％。文中揭示了草地蜘蛛种群结构及其季节变化。在牧草生育期中,狼蛛科的种类居优势,占51.97％,平腹蛛科和管巢蛛科各占11.93％、11.40％。7月份蜘蛛混合种群的成蛛中,雄蛛数量最少,占27.06％,其蛛态结构随季节而变化,6月成蛛数量最高,占40.78％。蜘蛛种群的数量消长,随作物、牧草生育期和利用年限不同而有差异。3月上旬平均气温4.7℃时,蜘蛛始出土,4月上旬气温7.2℃时,普遍在地面活动。温度和光照强度的日变化和季节变化,明显地影响蜘蛛日活动数量的变化。耕作和7月上旬的降雨,是影响草地蜘蛛数量的重要原因。

During 1981—1986,58 spcies of spider belonging 13 families werecolleted in a forage crop field at Huangyang Town,Wuwei County,Gansu Provice.From those,7 species had greater populations.Thespiders consituted 71.32% of the total population of predators.Theconstitution of population and its seasonal dynamics were revealed inthe paper.In the growing season,the species of Lycosidae were thedorminat (51.97%);the percentages of Gnaphosidae and Giubidae were11.93%,11.40% respectively.In April and May,the female was littlemore than male in the mixed population,and the amount of male de-creased to the least in July (only 27.06%).The constitution of agegroup varied with season.The number of adult was the greatest in June(40.78%),but the least in April and August (18.74%,11.16% re-spectively). When the average air temperature was at 4.7℃ on the 1st ten-daysin March,the spiders emerged out and became active on the groundsurface widespreadly when the air temperature raised to 7.2℃ on the1st ten-days in April.The daily and seasonal fluctuations of tempera-ture and light intensity might affect the daily and seasonal amounts ofactivity of spiders significantly.The tillage and precipitation were themajor factors affecting the population of spiders in the forage field.