Study on Frass Extruded by Larvae of Anoplophora glabripennis

Frass of longhorned beetle larvae plays an important role in natural enemies searching for their cerambycid hosts.By periodically collecting larval frass of Anoplophora glabripennis in field from April to June,the quantities of frass extruded by longhorned beetle larvae were studied.The result showed that the quantity of frass extruded by larvae firstly increased then decreased during investigation period before adult emergence.The average quantity of frass per hole per day was(0.030 2±0.002 1)g,and the maximum of frass quantity per hole per day was 0.319 4 g.The relationship between frass quantity,diameter at breast height of host tree,thickness and water quantities of bark,and diameter of frass-extruded hole were studied.Results showed that total frass quantity or maximal frass quantity per day of every frass-extruded hole only had direct relation with the size of hole during investigation period and were independent of other factors.In order to collect frass during investigation,adhesive tapes were used to cover frass holes,so micro-habitats under tape were established.More than thirty adults of Dastarcus helophoroides,an important natural enemy of A.glabripennis,were collected under tape during the investigation period.Results indicated that occurrence of D.helophoroides were consist with host mature larval stage or pupae stage for more parasitizing chances.