| Harmonia axyridis (Pallas) is an important predator insect, as well as a typical polymorphic species, it is also the main natural enemy insects of aphids, matsumura pine scale, mealybugs and other pests. Now being widely released for biological control of aphids and scale insects.This paper mainly study on genetic diversity of different splash stain of H. axyridis from the morphological, ecological, molecular level, and reveals their differences in genetic diversity, then can deeply understand the living conditions, Classification, evolutionary history and relationships of H. axyridis, forecast its future development trends, and establish the foundation for more effective biological integrated prevention and treatment.(1) Through survey on the spots of 2178 units of H. axvridis, 126 splash types were found, among them 15 splash types--15 spot types were not recorded in the past report. The results of diversity analysis showed that Monk index, Simpson diversity index and Shannon-Wiener index was 0.0579.0.901 and 1.56 differently.(2) The statistical results of probability of type showed that a spot 3 was the highest, while spots 9 and 1/2 were smaller. Different splash types of H, axyridis had a great difference in the proportion of male and female; particularly in the yellow-bottom groups, with the number of spots increase, the proportion of male types reduced. Through correlation study between length and width of the main groups of H. axyridis, the results showed significant differences in body length and width, and the aspect ratio varied significantly; the different splash types had a certain body size and shape variations.(3) Observed by scanning electron microscopy, antenna structure and the types and quantities of sensors on antennae of different splash types of H. axyridis were described; and a comparison between different splash types was made, the results showed that there were some differences between units of H. axyridis.(4) The ecological distribution, forest types, habitat plants, the time of its occurrence and climate change of overwintering adults of different splash types of H. axyridis were directly related. Its number and distribution hosts also had some differences at the same time and same terrain.(5) The spatial distribution of overwintering adults of different splash types of H. axyridis was mass distribution, and also accord with the negative binomial distribution.(6) In this experiment, the modified CTAB method, saturated NaC1 method and SDS and CTAB combining method were used for cornprehensive design, a set of simple, rapid, accurate, high-quality DNA extraction and purification technology was explored. (7) 12 polymorphic primers were selected from 40 random RAPD primers, through RAPD analysis on 9 different splash types of H. axyridis, 169 polymorphic sites were detected, the sites lie between 100 bp and 2000 bp, and its percentage lie between 34.32 and 65.68; 13 ISSR primers whose bands were clear and rich in polymorphism were selected from 40 primers. Through ISSR analysis on 13 different splash types of H. axyridis, 127 ISSR bands were amplified, including 120 polymorphic bands, and the polymorphic percentage is 94.49.(8) The consistency and credibility of ISSR and RAPD analysis: There was a high correlation between RAPD and ISSR (r=0.928, n=127), indicating that the two methods were highly consistant and suitable for detecting genetic diversity and genetic relationships in H. axyridis. However, both kinds of clustering analysis have some difference in individual splash types.(9) According to the clustering analysis of RAPD results of 9 different splash types of H. axyridis, the results showed that the genetic similarity index was between 0.46 and 0.58. The genetic similarity index is between 0.36 and 0.60 based on the ISSR analysis of the results.In short, through comparison on genetic diversity of different splash types ofH. axyridis from morphological, ecological and molecular level, different types have some differences in genetic diversity. It provided scientific basis for protection, development and use of natural enemy insects for human. |
PDF Full Text Request