Abstract: 【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.  

Key words: Tetrigus lewisi, Monochamus alternatus; Tenebrio molitor, predation, bio-control agent