一种红脂大小蠹天敌切头郭公虫Clerus sp.生物学初探

Biological study of the decapitator checkered beetle Clerus sp., a natural enemy of the invasive bark beetle Dendroctonus valens

红脂大小蠹Dendroctonus valens LeConte,原产于北美,于20世纪80年代随木材贸易传入我国山西,是一种危害油松、白皮松、华山松等松科植物的毁灭性入侵害虫。本文对红脂大小蠹天敌切头郭公甲虫Clerus sp.的基本生物学特征进行了初步探讨。野外诱捕发现,红脂大小蠹诱剂3-蒈烯能诱捕到切头郭公甲虫Clerus sp.,并观察到此郭公甲虫紧抱红脂大小蠹的捕食行为及红脂大小蠹头部被切下的残骸。诱捕动态监测表明切头郭公甲虫与红脂大小蠹的发生在时间和数量上具有跟随关系。室内测定结果显示切头郭公甲虫平均体重约15.5 mg且个体大小与捕食能力呈正相关。切头郭公虫平均存活时间约38 d,10 d内平均每头郭公虫捕食3头红脂大小蠹,最多达8头。行为嗅觉试验表明切头郭公虫Clerus sp.对红脂大小蠹诱芯反应敏感,红脂大小蠹信息素组分frontalin不能增加其对红脂大小蠹诱芯的敏感性。本研究初步探明了红脂大小蠹天敌切头郭公虫Clerus sp.生物学特征,其较长捕食周期和较强的捕食能力决定其可作为红脂大小蠹的生物防治因子具有一定的优势和较好的天敌应用前景。

The red turpentine beetle Dendroctonus valens LeConte, native to North America, is one of the most destructive invasive forest pests in China, having killed more than 6 million pine trees since its first outbreak in 1999. Most research has focused on the chemical communication of this species and relatively little is known about its natural enemies. In this paper we investigate the potential of using the decapitator checkered beetle （ Clerus spp. ） to control the red turpentine beetle. Field trapping showed that Clerus sp. is attracted to a lure （3-carene） extracted from D. valens and that some D. valens bark beetles were decapitated. Moreover, decapitator beetles took flight out about one week after the flight of D. valens and its numbers were correlated with those of D. valens. Laboratory experiments showed that decapitator beetles weigh about 15.5 mg on average and that its predatory capability was significantly correlated with its body weight. Decapitators survived, on average, 38 d and the longest-lived survived 53 d, and could prey on an average of three D. valens adults per 10 days （range 1 to 8 individuals）. Olfactory assays showed that decapitator beetles were attracted to a lure for D. valens and that the D. valens aggregation pheromone frontalin did not increase the attractiveness of the lure. These results show the potential of using Clerus sp. to biologically control the invasive bark beetle D. valens in China.