入侵种喜旱莲子草天敌——莲草直胸跳甲的生物学特性

喜旱莲子草(Alternanthera philoxeroides(Mart.)Griseb.)是一种水陆两栖的重要外来入侵种,是中国国家环保局公布的首批9种重要外来入侵植物之一。莲草直胸跳甲Agasicles hygrophila Selma&Vogt是目前控制喜旱莲子草最有效的天敌昆虫。对该虫的形态特征和行为习性作了描述。卵块成"八"字形,孵化需要高湿度的保持;幼虫有趋嫩性,幼龄幼虫一般取食叶片的下表皮,2、3龄幼虫取食量很大;老熟幼虫在茎秆上咬一个圆形的洞,进入茎秆中化蛹,并咀嚼咬下的植物组织,吐出后塞住洞口;成虫羽化6d后交尾,雌虫产卵于顶叶的背面。

Bionomics of Agasicles hygrophila, as the natural enemy for invasive weed, Alternanthera philoxeroides

Alligatorweed, Alternanthera philoxeroides (Mart.) Griseb., is one of the most serious invasive weeds. It is also one of the first listed 9 key invasive plants in the Chinese State Biodiversity Report. Flea beetle, Agasicles hygrophila Selma & Vogt, a host-specific natural enemy, controls the weed successfully in the world. Morphological characters and behaviors of A. hygrophila were described in this paper. The eggs are arranged in 2 parallel rows, the longitudinal axis of each of the eggs of each row being oblique to the midline between the rows. Successful completion of the incubation period is dependent on sustained high humidity. Larvae preferred the succulent apical growing tips and leaves of the 1st, 2nd, 3rd and 4th pairs. The young larvae attack and destroy the lower epidermis of the leaf. The 2nd-and 3rd-stage larvae consume more leaf tissue. Pupation begins after the 3rd-stage larva has satisfied its feeding prerequisite. The insect chews a circular hole into the internode, pulls its body through the hole. The ingested stem tissue from the entrance hole is masticated and regurgitated to form a plug. Adults begin to mating in 6d after emergence. The female oviposits on the underside of an apical leaf.