Population Genetic Analysis On Elytral Color Polymorphism Of Harmonia Axyridis In JILIN

The lady-brid beetl, Harmonia axyridis, Pallas, was mainly native to Asia. Now it spread rapidly around the world. It is a highly polymorphic Coccinellidae with a wide geographic. In the past, much research was done on the basic biology and application of this species in the biocontrol of aphids. The previous studies of taxonomy and genetics have also brought about many publications on this beetle. Tan found that the elytral color polymorphisms of Harmonia axyridis can heredity and associated with a series of multiple alleles. The other studies also showed that frequency distribution among these types changes with time and space. This implies that these types have different adaptation to environment.In this paper, we analyze the statistics of the Harmonia axyridis population, which were collected from the city of Changchun,Shuangyang,and Dunhua in 2007 and 2008.According to the study of taxonomy, the beetles were categorized into four splash-types, succinea, conspicua, spectabilis and axyridis.We study the change of the gene frequency and the phenotype frequency with the time and contrast the differentiation between different area. We gathered the death beetles which could not pass through the winter to compare to the live beetles before the next winter. All the work above we had done is to find out the correlated relationship between the gene frequency of the spot and the local natural environment factors, such as the climatic and the latitudinal effect. We also discuss the reason of this correlation trend between the gene frequency (or phenotype frequency) and the local average temperature factors via using the regression analysis. The conclusions are as follows:1. In Changchun, The past 20 years have shown that the elytral color gene frequency of the conspicua has been rising, and the elytra color gene frequency of the succinea has been declining.2. The gene-frequency of each elytral color type makes no difference during wintering period.3. In small area, the gene-frequency of each elytral color in each winter clusters is basically the same.4. The correlation between elytral color gene frequency (or phenotype frequency) and average temperature variables are significant.5. The fluctuation of elytra color gene frequency (or phenotype frequency) changing with time in low latitudes is stronger than that in the high latitudes.