我国草地螟的寄生蜂及其与寄主的关系

为了阐明草地螟Loxostege sticticalis L.（鳞翅目：草螟科），我国三北地区农业生产重大害虫的天敌资源及其对寄主种群的控制作用，本文对我国草地螟的寄生蜂种类，及其对寄主虫态（龄期）的选择和寄生类型进行了总结。所得的主要结果为：我国已知的草地螟寄生蜂有26属36种。其中属于赤眼蜂科的4种、巨胸小蜂科的1种、茧蜂科的17种和姬蜂科的14种。在这些种类中，有卵期寄生蜂4种，幼虫寄生蜂32种。在幼虫寄生蜂中，有卵-幼虫寄生蜂3种，幼虫-蛹寄生蜂2种。另外，寄生蜂可寄生1～5龄幼虫，但从龄期较低的幼虫开始寄生的种类比从龄期较高开始寄生的多。再加上从1龄开始寄生的部分种类在寄主幼虫发育到5龄时已经成熟，因而可在3龄寄主发现的寄生蜂种类较多，多样性指数也较高。我国草地螟茧中的寄生蜂大多是从幼虫期开始寄生，是否存在从预蛹或蛹期开始寄生的种类尚待明确。最后，这些种类以初寄生、单寄生和内寄生蜂为主，而重寄生、多寄生和外寄生蜂较少，分别为2、4和2种。

Hymenopteran Parasitoids Attacking the Beet Webworm,Loxostege sticticalis in China

To understand the species of natural enemies and roles they played in the population dynamics of the beet webworm, Loxostege sticticalis L. (Lepidoptera:Crambidae), a cosmopolitan insect pest of crops and fodder plants in northern China, we reviewed the species, their targeting host stages and parasitic patterns of the hymenopteran parasitoids attacking L. sticticalis in China. There are totally 36 species in 26 genus documented in China. Of which there are 17 braconids, 14 ichneumonids, 4 trichogrammatids, and 1 preilampid. Among these parasitoids, 4 species attack egg and 32 attack larvae. In the later, there are 3 egg-larval and 2 larval-pupal parasitoids. The larval parasitoids can parasitize 1^st to 5^th instar, with more species parasitizing young than old larvae. Several species parasitizing the 1^st instar complete their development before the host larvae enter into 5^th instar. Consequently, the number of parasitoid species present in the 3rd instar is usually more than that found in the 4^th to 5^th instars. Besides, parasitoids found in cocoons are mainly larva-pupa parasitoids, while there are no confirmed species parasitizing pre-pupa and pupa in China. In terms of parasitic patterns, majority of them are primary parasitoids, endoparasitoids, and solitary parasitoids, only a few species are ectoparasitoids (2), gregarious parasitoids (4) and hyperparasitoids (2).