不同龄期异色瓢虫对核桃全斑蚜的捕食功能反应

核桃全斑蚜是近年来新发现的一种核桃树上的新害虫，为明确异色瓢虫对核桃全斑蚜的控害潜能，室内研究了不同龄期异色瓢虫对不同密度核桃全斑蚜的捕食能力。结果表明：不同龄期异色瓢虫对核桃全斑蚜的捕食功能反应均符合Holling-Ⅱ型圆盘方程。异色瓢虫各龄幼虫及成虫对核桃全斑蚜的日最大理论捕食量由大到小依次为4龄幼虫、雌成虫、雄成虫、3龄幼虫、2龄幼虫和1龄幼虫； 4龄幼虫对核桃全斑蚜的瞬间攻击率最强，处理时间最短。异色瓢虫的寻找效应随着猎物密度的增加而降低，4龄幼虫寻找效应最强。即异色瓢虫对核桃全斑蚜具有较强的捕食能力。

Predatory Functional Response of Different Stages of Harmonia axyridis Pallas on Panaphis juglandis Goeze

Panaphis juglandis Goeze is a recently reported pest of walnut trees. The biological control potential of Harmonia axyridis Pallas on P. juglandis was assessed by examining the functional response of H. axyridis to various densities of P. juglandis under laboratory conditions. The results showed that the functional response of the 1st to 4^th instar nymphs and adults of H. axyridis to P. juglandis fitted well with the Holling-II model. The daily maximum theoretical predation of the nymphs and adults of H. axyridis on P. juglandis in descending order were 4^th instar nymph, female adult, male adult, 3^rd instar nymph, 2^nd instar nymph, and 1^st instar nymph. The searching efficiency of H. axyridis decreased with the increase of prey density. The 4^th instar nymphs of H. axyridis showed the highest attacking efficiency, the shortest handling time, and the highest searching efficiency on P. juglandis. These results show that H. axyridis is an effective predator against the large walnut aphid.