Effects of nest collecting on the population recovery of Polyrhachis vicina Roger (Hymenoptera:Formicidae)
鼎突多刺蚁(Polyrhachis vicina Roger)蚁群的采收与恢复效应

Polyrhachis vicina Roger,a species of ant in the south of Chinese mainland,is used as Chinese medicine for rheumatoid arthritis.In mountain areas of Zhejiang Province,those mountain slopes nested by this ant were enclosed by local peasants for protection and collection of this ant.But how and when to collect this ant in the case of keeping the equilibrium of population and of reaching the highest harvest yield in a mountain slope need to be investigated.In this paper,effects of different nest collecting measures on the population recovery of the ant P.vicina Roger were studied in Yongkang and Pingyang counties of Zhejiang Province.Each mountain slope selected as the measured site located on the hill,with the size of about 2000 m 2.The vegetation on the hill includes mason pine,China fir and other plants,such as Quercus fabri,Smilax china,Ilex cornute,Rosa bracteata,Symplocos caudate,Glochidion puberum,Lespedeza formosa, and Arundinella setosa. The secretion from Matsucoccus spp.on the mason pine and from Lachuns tropicalis on Quercus fabri is the major food resource for this ant.3~4 ant nests were collected each month,and the caste composition in each colony was measured.For the colony,the population was grown from winter to summer and descended after early autumn.Egg,larva,worker,queen and alate male appeared yearly,but pupa appeared only from April to November and gyne only from September to November.The colonial individual in the maternal\|nest is more abundant than that in the side\|nest.50% of nest density was moved from different mountain slopes in spring (April),summer (July)and autumn(October)respectively.Then their recovery rates of nest density show that the summer is the most suitable season for collecting nests and the spring collection is harmful for population equlibrium of ant.During collecting,it is best to collect the side\|nests and to keep the maternal nest as intact as possible.18 mountain slopes were selected as measured sites of collection intensity (0%,25%,50%,and 75% of nest density in a slope were moved out respectively)in the summer (August).The result shows that the nest density in the 75% collection intensity dropped rapidly after two months and remained only 20% of nest density.Fortunately,in the 25% collection intensity the nest density increaseed instead of decreased in four months after collection.It is inferred that the population decreased appropriately in a mountain slope would compensate the population growth.It is suggested that 25%~35% collection of total nest density should be favorable to keep the population equilibrium.Cash crops hosted by aphids,such as cowpea and cucumber,were planted in 9 mountain slopes.After one month, Aphis gossypii and Aphis craccivora were found on these cash crops.For comparison of population recovery between the mountain slops with and without this plantation,it shows that plantation of cash crops hosted by aphids in the field with the ant is beneficial to increase the ant popula