异色瓢虫若虫对麦三叉蚜的捕食作用

Predation of Harmonia axyridis nymph on Schizaphis graminum

研究表明，异色瓢虫高龄若虫捕食麦二叉蚜的功能反应为ＨｏｌｌｉｎｇⅡ型反应，喜好捕食低龄若蚜；在４０℃下捕食率最低，１０℃次之，２５℃最高．在１０～２５℃内捕食率ｙ与温度ｘ的关系为ｙ＝２８．１３０３＋２．６６６５ｘ，在２５～４０℃内为ｙ＝１９９．９２７５－３．６４２ｘ；在种内干扰条件下，其捕食作用率Ｅ与开敌密度Ｐ的关系为Ｅ＝０．６８９７Ｐ－０．７９３０，搜索常数Ｑ为０．６８９７，干扰系数ｍ为０．７９３０；其分摊竞争强度Ｉ与异色瓢虫密度Ｐ的关系为Ｉ＝０．０４００＋１．０３８３ｌｏｇＰ．

The functional reaction of old Harmonia axyridis nymphs preying on wheat aphides shows the Holling Ⅱ type, i. e., preferring to feed on young aphid nymphs. The predation ratio is the lowest at 40C and the second at 10℃, being the highest at 25℃. At the range of 10～ 25℃, the relationship between predation ratio (y) and temperature (x) is y= 28. 1303+ 2. 6665 x, and at 25～40℃,y=199. 9275 - 3. 642x. Under intraspecific interference, the relationship between predation ratio (E) and natural enemies density (P) is E= 0. 6897P-0.7930, searching constant Q is 0. 6897, disturbing coefficient(m )is0. 7930.The relationship between intensity of scrambling competition (I) and density of H.axyridis(P) is I= 0. 0400+1. 0383 logp.