七星瓢虫捕食棉蚜的功能反应

用罩笼方法测定了七星瓢虫成虫捕食棉蚜的功能反应。瓢虫一日捕蚜量(Na)用蚜虫日增长倍数(R)与初始蚜量之乘积减去剩余蚜量求得。瓢虫捕食蚜量的功能反应曲线符合 Holling—Ⅱ型,(a′=0.77;Th=0.00259)。测定了瓢虫干扰常数(m)和寻找常数(Q),(m=0.6284;Q=0.487)。根据功能反应曲线推论,当棉蚜与瓢虫共存于一个封闭系统内时,棉蚜的种群动态模型为N_((t+1))=RN_((t))exp((-0.77P)/(1+0.77×0.00259N_((t)))当 R 与 P 取定值时,N_((t))对 N_((t+1))的上升或下降起决定性作用。

The Functional Response of Lady Bird Attacking on Aphids

The functional response of lady bird (Coccinella septempunctata L.) to prey on cotton aphids (Aphis gosspii G.) was tested in cages.The number of aphids attacked (Na) was calculated as Na=R .where,Rn-n=aphid rate of population increase;n= total number of ahids bing counted on the 3rd day before predation;n= surviving after 24 hrs of predation on the 4th day.A functional response roughly fitting Holling--2 was obtained(a'=0.77;Th= 0.00259).Hassell's mutual interference equation was confirmed(Q=0.487;m=0.6284).It is reasoned that the population of aphids,together with lady birds within an enclosed system would be confirmed to an exponential increase or decrease.