室内条件下莱氏猛叩甲对松墨天牛和黄粉虫的捕食能力

【目的】本研究旨在明确莱氏猛叩甲Tetrigus lewisi老熟幼虫分别对黄粉虫Tenebrio molitor和松墨天牛Monochamus alternatus末龄幼虫和蛹的捕食量的差异,评估莱氏猛叩甲的捕食能力,为松墨天牛M.alteratus的有效治理找到潜在的高效生物防治因子。【方法】于2014年11月在浙江富阳昌东村马鞍山砍下松墨天牛虫害木,通过林间野外调查,明确松墨天牛和莱氏猛叩甲的发生情况;将野外采集到的莱氏猛叩甲幼虫带回室内,分别饲喂黄粉虫和松墨天牛的末龄幼虫和蛹,每天记录捕食量,确定莱氏猛叩甲的捕食能力。【结果】野外调查中,我们在松墨天牛幼虫蛀食的坑道中发现了莱氏猛叩甲幼虫和松墨天牛幼虫被取食后的残体;在采集到1 094头松墨天牛幼虫的危害木内,共采得莱氏猛叩甲末龄幼虫36头,约为松墨天牛幼虫数量的3%。室内捕食实验表明,5 d内莱氏猛叩甲捕食黄粉虫幼虫总量为3.2头,平均每天捕食约0.6头,而捕食松墨天牛幼虫总量为8.0头,平均每天捕食约1.6头,莱氏猛叩甲对松墨天牛的总捕食量显著高于对黄粉虫幼虫的总捕食量(P0.0001);4 d内莱氏猛叩甲捕食黄粉虫蛹总量为5.6头,平均每天捕食约1.4头,而捕食松墨天牛蛹总量为7.8头,平均每天捕食约2.0头,莱氏猛叩甲对松墨天牛蛹的捕食量显著高于黄粉虫蛹(P=0.028)。回归分析还表明,莱氏猛叩甲幼虫的捕食量不受叩甲个体大小的影响。【结论】莱氏猛叩甲普遍分布在松墨天牛发生区,同时发现松墨天牛被取食后的残体,表明莱氏猛叩甲是松墨天牛的捕食性天敌。莱氏猛叩甲均能捕食黄粉虫和松墨天牛的幼虫和蛹;相比于捕食黄粉虫,莱氏猛叩甲对松墨天牛的幼虫和蛹具有更好的捕食效率,具有很好的生物防治前景,是未来松墨天牛治理潜在高效生物防治因子。

Predatory capability of Tetrigus lewisi (Coleoptera: Elateridae) to the Japanese pine sawyer,Monochamus alternatus (Coleoptera:Cerambycidae) and the yellow mealworm,Tenebrio molitor (Coleoptera:Tenebrionidae) under laboratory conditions

Aim] This study aims to evaluate the predatory capability of Tetrigus lewisi larvae to final instar larvae and pupae of the yellow mealworm,Tenebrio molitor and the Japanese pine sawyer,Monochamus alternatus by feeding experiment in the laboratory,so to find an effective bio-control agent for the management of the pine sawyer.Methods] To confirm the occurrence of M.alternatus and T.lewisi,field survey was carried out in November 2014 at a forest of Mt.Maanshan,Changdong,Fuyang County of Zhejiang Province by cutting down the infested trees by M.alternatus larvae and counting the number of each species by dissecting galleries made by beetle larvae.T.lewisi larvae were brought back indoor,and fed with final instar larvae and pupae of T.molitor and M.alternatus,respectively,to estimate the predatory capability of T.lewisi larvae.Results] In the field survey,we found both T.lewisi larvae and residual body of the Japanese pine sawyer in the galleries made by M.alternatus larvae.Totally,36 T.lewisi final instar larvae and 1 096 M.alternatus larvae were collected in the infested dead pine trees,with the population density of the former being about 3％ of the latter.Indoor predatory experiment showed that one T.lewisi larva preyed on 0.6 and 1.6 larvae of T.molitor and M.alternatus per day,respectively.The total average number of T.molitor larvae preyed in five consecutive days was 3.2 individuals,which was significantly lower than that of M.alternatus larvae preyed (8.0 individuals) (P ＜ 0.0001).Moreover,T.lewisi larva could prey on both pupa of T.molitor and M.alternatus.The average preyed number of T.molitor and M.alternatus pupae was 1.4 and 2.0 individuals per day,respectively.The total average number of T.molitor pupae preyed in four consecutive days was 5.6 individuals,which was significantly lower than that of M.alternatus pupae preyed (7.8 individuals) (P =0.028).Furthermore,regression analysis showed that the predation amount of T.lewisi was not correlated with its body size.Conclusions] Field survey confirmed that T.lewisi is widely distributed in the galleries of M.alternatus larvae,showing that T.lewisi is a natural enemy of the Monochamus beetle.T.lewisi larvae prefer to prey on larvae and pupae of M.alternatus rather than on those of T.molitor,showing promising prospect of using the natural enemy T.lewisi for management of Monochamus beetles.