Effect of Population Density on the Migration Behavior of Hepialus sp. Larvae

Purpose To explore the relation between the migration and population density of Hepialus sp. larvae, on the one hand, it is possible to determine the suitable breeding density of the moth in a certain space; on the other hand, it is possible to find out the reasons for the low breeding rate of 2^nd larva of some species, witch could help to make out the scientific breeding plan of the Hepialus sp. larvae, to improve the survival rate and to increase the intensive use level of breeding space.

Methods Three species of Hepialus sp. larvae were fed and observed till pupa stage under the same laboratory conditions except the population density, the emigration numbers of initial larva were tallied, the migration distances of the larvae developing from the end of second instar larva stage to pupa stage in soil were measured.

Results The emigration numbers of different species were different, so did the duration days of emigration; the emigration numbers of H. renzhiensis Yang were the most and their migration period was the longest, followed by H. baimaensis Liang, and H. yunnanensis Yang, Li et Sheng came the last; the migration of Hepialus sp. larvae took place in the initial larva stage, their larvae dispersed in soil slowly and didn’t moved out from the soil after the end of second instar larva stage, they developed different distribution pattern at last.

Conclusion Different species of Hepialus sp. had own migration behavior. The indoor breeding plan should be made in accordance with the species to prevent the loss of initial larvae caused by high initial breeding density; the breeding space should be suitable for the survival numbers and the distribution pattern of the species of Hepialus sp. from the end of second instar larva stage. The research results provided an important scientific basis for rapid propagation of Hepialus sp.