不同猎物饲喂对南方小花蝽捕食量和喜好性的影响

为探讨南方小花蝽对不同猎物的捕食喜好性,室内用西花蓟马、蚕豆蚜、二斑叶螨、混合饲料(同时饲喂3种猎物)分别饲喂南方小花蝽驯化两代,研究了4种饲喂处理的南方小花蝽初孵若虫、5龄若虫和雌成虫对西花蓟马、蚕豆蚜和二斑叶螨的捕食量和喜好性。结果显示不同猎物饲喂处理驯化的南方小花蝽1龄若虫对同一种猎物的捕食量和喜好性均不存在显著差异。南方小花蝽5龄若虫和雌成虫对某种猎物的捕食量因前期取食的猎物种类不同而有显著差异。南方小花蝽5龄若虫和雌成虫均表现出对西花蓟马2龄若虫的正喜好性。蚕豆蚜饲喂处理的5龄若虫和雌成虫对蚕豆蚜表现出正喜好性,除二斑叶螨饲喂处理外其余3种处理的南方小花蝽5龄若虫和雌成虫均表现出对二斑叶螨的负喜好性。以上结果表明4种饲喂驯化处理的南方小花蝽1龄若虫的喜好性不受前期取食猎物的影响,但5龄若虫和雌成虫对前期取食过的猎物的喜好性增强,存在一定的学习行为。

Effect of different preys on the predation and prey preference of Orius similis

The genus Orius is a group of general predators and consumes a variety of pests including mites, thrips, aphids, eggs and young larvae of moths and other small, soft-bodied insects. It is an important biological control agent and plays an important role in controlling many pests. Researches on the effect of different preys on the predation and prey preference of Orius can provide basis for effective use of the agent in biological control. The predation and preference of newly hatched nymph, fifth instar nymph, female adult of O. similis to 3 species of preys, i.e., (Frankliniella occidentalis, Aphis craccivora, Tetranychus urticae and their combinations), were studied. The results showed that 1^st instar nymph of the predator, acclimated by feeding different preys, had no significant difference on predation capacity and preference to the prey. Comparison of C_i with null hypothesis showed that the preference of 1^st instar nymph of the predator to F. occidentalis was positive under 4 prey treatments with no preference to A. craccivora. There was no preference to T. urticae when feeding on T. urticae, while the preference to T. urticae was negative on other treatments. Fifth instar nymph of the predator, acclimated by feeding different preys, had a significant difference in predation capacity and preference to the prey, significantly increasing the predation to prior feed. For example, the preference to F. occidentalis was biggest with the value of 0.2580, when O. similis had experienced feeding on F. occidentalis. The predatory capacity and preference to A. craccivora was biggest when O. similis has experienced feeding on A. craccivora. The predatory capacity and preference to T. urticae significantly increased when feeding on T. urticae than those of feeding on other preys. Comparison of C_i with null hypothesis showed that the preference of 5^th instar nymph to F. occidentalis was positive under 4 prey treatments, and the preference to A. craccivora was positive when feeding on A. craccivora. The preference to T. urticae was negative except feeding on T. urticae. The predatory capacity of female adults to F. occidentalis was not significantly different when feeding on any prey. The predatory capacity to A. craccivora was bigger when feeding on A. craccivora and mixed preys than feeding on F. occidentalis and T. urticae. The predatory capacity to T. urticae was bigger when feeding on T. urticae and mixed preys than other treatments. The preference of female adults of O. similis was similar to 5^th instar nymph under different feeding treatments. The preference was strengthened when feeding on the pre-feed prey. The above results indicated that the predatory capacity and preference of 1^st instar nymph did not influenced by pre-fed. Prior feeding experiments had significant effects on the predation and preference of 5^th instar nymphs and female adults, so some learning behaviors may exist in O. similis.