Conserving Picoides Major With Artificial Nests For Controlling Anoplophora Glabripennis (Coleoptera: Cerambycidae)

Asian longhorned beetle Anoplophora glabripennis (Motschulsky) (Coleoptera:Cerambycidae) is a major polyphagous wood-boring beetle in China, which broke out heavily in three-north shelter forests and caused great losses after the 1980s. As one of the natural predators of A. glabripennis, great spotted woodpeckers Picoides major (Linnaeus) are endemic to three-north shelter forest and widely distributed in three-north shelter forest. For P. major fed on poplar longhorned beetles and obviously depressed their population density to some extent, in this study, we combined the attract and conservation of P. major wulashanicus Cheng et al. with ecological control A. glabripennis in agroforestry in Wulate Qianqi County of Inner Mongolia Autonomous Region. This paper consummated the vacancy of systematic study on attacting and conserving forest beneficial birds for natural controlling forest pests. The main results were as follows.1. Natural nests of P. major were investigated in summer 2005, summer 2006, and spring 2007, respectively. The results showed that P. major often selected Salix matsudana for excavating nests, but big mature poplar trees (Populus spp.) also could be chosen. Most of nests were often found with a protuberance above entrances or with a downward sloping gradient, or both. The average nest height was 5.2±0.1 m, and nest height selection by P. major was not significant. However, the average height of breeding nests (5.4±0.5 m) was often higher. The average vertical diameter (VDE) of nest entrances was 5.27±0.07 cm and the average horizontal diameter (HDE) was 5.66±0.11 cm, but there were no significant lineal relation between them, and the size of nest entrances was almost fitted. The compass orientation of 61.43% nest entrances was towards north, northeast and east, and only 5.22% towards south and southeast.2. Due to the deficiencies of traditional artificial nests and characteristics of natural nests, totally 13 types of artificial nests made of Populus simonii×(Populus pyramidalis+Salix matsudana) cv. Poplaris and S. matsudana were constructed using orthogonal design. The results showed that the attraction of cavity-drilled artificial nests was better than that of traditional artificial nests, and an optimal artificial nest was made of cavity-drilled P. poplaris logs with naturally small protuberance and naturally bark surface. When installion distance between artificial nests was over 50 m (D≥50 m) and under 20 m (D≤20 m), the occupancy rate of nests was 37.50% and 23.93% respectively, and the difference between them was extremely significant. The utilization rate and occupancy rate of nests inatalled at 3.5 m height (55.56% and 28.34%) was lower than those installed at 4.5 m height (83.33% and 44.45%). Furthermore, artificial nest installed on the north side of trees was optimal, and the entrance orientations distribution of occupied nests was similar to that of natural nests.3. At the peak of nestling period, feeding times for each nestling in artificial nests (17.27 times) were almost the same as that in natural nests (16.73 times). Two feeding peaks were found at 6:00-7:00 and 19:00-20:00, and one feeding trough was found at 11:00-13:00 every day. Feeding times for nestlings by male P. major were often about 40 times one day, so were female. But the male often fed more times than the female, especially in bad weather. Moreover, the period for feeding nestlings by the male was often 1-2 min while the female was often less than 30 s. Breeding success in artificial nests (85.33%) was almost the same as that in natural nests (82.50%), but hatching rate in artificial nests was obvious lower.4. The pecking rate of P. major on A. glabripennis was investigated in winter. Results showed that the pecking rate of P. major on A. glabripennis was 14.91% in slightly damaged plots,19.86% in medium damaged plots and 13.93% in heavily damaged plots, respectively. Above 6 meters height of infested trees trunks, the pecking rate was 27.25%, which was significantly higher than that under 6 meters height (16.18%). Results also indicated that P. major preferred old A. glabripennis larvae to young larvae in the damaged plots and tree heights with a higher pecking rate. In indoor research, investigative results of foraging behavior showed that the foraging rate of P. major on A. glabripennis larvae and granular meat was 100%, on moths was 58.33% and on seeds was 41.67%. The foraging rate of P. major on visible A. glabripennis larvae and granular meat was 91.67% and 86.11%, which was significant higer than that of invisible ones (22.22% and 19.44%), respectively. However, P. major also foraged for more seeds or invisible preys when little food was supplied. 5. Attraction of artificial nests to P. major was the best in winter, better in spring and the worst in summer. Attraction to P. major was very bad in the place where P. major population was few or enough nest trees existed. In the first two years, the utilization rate and occupancy rate of artificial nests was increased sharply, and often stopped in the third or fourth yesr. Compared to traditional artificial nests, cavity-drilled P. poplaris artificial nests designed in 2007 had better attraction and could be used longer. The pecking rate of P. major on A. glabripennis in attracting plots was the highest in winter (33.23±1.39%), higher in spring (27.82±2.06%) and the lowest in summer (5.45±0.64%). Attracting P. major with artificial nests could enhance the control effect on A. glabripennis, especially could depress the population density of A. glabripennis effectively in slightly and medium damaged area. While the population density of A. glabripennis was high in heavily damaged area, other prevention measures should be used simultaneously.6. In Wulate Qianqi County, seven prevention measures, such as cutting infested trees, sprout regeneration, top trunk-cutting, trunk injecting insecticides, spray Luseweilei contacted-breaking microcapsules pesticide, reasonable allocation of varied tree species, attracting P. major with artificial nests, were often used for controlling A. glabripennis. However, new mechanical wounds and sprouts of tree stumps were often infested by poplar clearwing moth P. tabaniformi, and insecticide often caused resistance to pests and killed natural enemies. Compared to the other six measures, attracting P. major with artificial nests for controlling A. glabripennis was a labor and time saving measure, and it did not pollute the environment and controlled sustainably. In addition, the data from local forest department showed its economic efficiency was about 1.96 million RMB every year. It could also keep and improve the quality of ecological environment and achieve the sustainable development of environment and economic. Considering the limitation of artificial attract, we suggested artificial attract mainly supplemented by other prevention measures as integrated pest management for controlling poplar longhorned beetles in shelter plantation.