七星瓢虫对豌豆修尾蚜的捕食功能反应

【目的】探明七星瓢虫(Coccinella septempunctata)各虫态对豌豆修尾蚜(Megoura crassicauda)的捕食功能反应,为田间应用七星瓢虫防治豌豆修尾蚜提供科学依据。【方法】在实验室条件下,设置不同虫态七星瓢虫与不同密度梯度的豌豆修尾蚜3龄若虫,通过控制单一变量法探究七星瓢虫各虫态对豌豆修尾蚜3龄若虫的功能反应和搜寻效应、七星瓢虫成虫种内干扰反应和同比例种内干扰反应,以及不同温度和空间大小对七星瓢虫成虫捕食作用的影响。【结果】七星瓢虫各龄期幼虫和雌雄成虫对豌豆修尾蚜的捕食功能反应均符合HollingⅡ型模型。不同虫态七星瓢虫对豌豆修尾蚜的捕食效能(a'/T_h)从高到低排序为4龄幼虫、雌成虫、雄成虫、3龄幼虫、2龄幼虫、1龄幼虫。幼虫捕食量随龄期增加而增加,4龄幼虫最高,雌成虫高于雄成虫。七星瓢虫各虫态对豌豆修尾蚜的寻找效应均随着猎物密度的增加而逐渐降低。七星瓢虫成虫自身密度对豌豆修尾蚜的捕食作用影响符合Hassell模型。七星瓢虫成虫个体间存在种内干扰,并随着自身密度的增加,干扰增强,平均捕食量降低。七星瓢虫种内干扰反应的数学模型为E=0.7954P-0.882。在不同空间豌豆修尾蚜数量一定的条件下,七星瓢虫捕食量随空间增大而减小,表明空间增大影响七星瓢虫搜寻猎物。在光照、湿度等条件一定时,随着温度的升高,七星瓢虫成虫对豌豆修尾蚜的捕食量增加,超过32℃后则下降,但其在38℃时仍保持较高的捕食能力。【结论】七星瓢虫对豌豆修尾蚜有较强的捕食能力,其温度适应性广泛,空间大小对捕食量有一定影响。

Predatory functional response of Coccinella septempunctata to Megoura crassicauda

【Objective】The predatory functional response of different stages of Coccinella septempunctata to Megoura crassicauda was explored,which would provide scientific basis for control of M.crassicauda by means of C.septempunctata in field.【Method】Under laboratory conditions,C. septempunctata in different stages and different density gradie-nts of the 3rd instar nymphs of M.crassicauda were prepared. By controlling single variable method,the functional response and search effect of C.septempunctata in different stages to the 3rd instar nymphs of M.crassicauda were studied,intraspecial interference response of adult C.septempunctata and intraspecial interference response at the same ratio were also studied,as well as the effect of different temperature and space size on predation of adult C.septempunctata.【Result】The results showed that the functional response of the 1st to the 4th instar nymphs and adults of C. septempunctata to M. crassicauda fitted well with the Holling-Ⅱ model. The predation efficacy(a'/T_h) of the different insect states of C.septempunctata on M. crassicauda was 4th instar larvae,adult females,adult males,3rd instar larvae,2nd instar larvae and 1st instar larvae in descending order. Larval predation increased with age,4th instar larvae was the highest,and female adults were higher than male adults. The search effect of each stage of C. septempunctata on M. crassicauda decreased with increasing prey density. The effect of the adult C. septempunctata's density on the predatory effect of M. crassicauda was consistent with the Hassell model. There was intraspecific interference among adult C. septempunctata,and as their own density increased,interference increased and average predation decreased. The mathematical model for the intraspecific disturbance response of C. septempunctata was E=0.7954P-0.882. Under the condition of a certain number of C. septempunctata in different spaces,the predation amount of C. septempunctata decreased with the increase of space,which indicated that the increase of space affected C. septempunctata's preying. Under the conditions of constant light and humidity,the predation of adult C. septempunctata increased with the increase of temperature,and decreased when the temperature exceeded 32 ℃,but the predation capacity of adult C. septempunctata remained high at 38 ℃.【Conclusion】C. septempunctata has a strong predatory ability on M. crassicauda,with a wide range of temperature adaptations,and space size has some effects on the predation amount.