| Brontispa longissima（Gestro）is a pest of hispidae in Coleoptera,which can damage almost all palm plants.In order to control this pest,Tetrastichus brontispae Ferrière was introduced from Taiwan Province in October 2004,and has been bred till now.In this study,two laboratory populations of T.brontispae,rejuvenation（Wenchang laboratory population,abbreviated as WC）and conservation（Danzhou laboratory population,abbreviated as DZ）,were used to analyze the degree of genetic variation of the two populations based on mitochondrial genes,compared the parasitic ability of the two populations,Analysis of the differences between the two populations at the molecular level based on transcriptome data and re-observed the adult behaviors of WC population.The main conclusions are as follows:（1）By analyzing the mitochondrial genes of two populations,it was found that the COI,COⅡand CYT-B of the two populations showed significant A/T bias.All the three genes contained only less vaiation sites（0.3%-1%of the total length）,and were all parsimony-informative sites.The genetic distance between populations was very close（0.2%-0.8%）.The results showed that the degree of variation between the populations is low,and the genetic relationship was close.（2）Through genetic diversity analysis,COI and CYT-B genes of DZ population showed high Haplotype diversity and low Nucleotide diversity.The phylogenetic tree of the three genes showed that all WC individuals and some individuals of DZ populations clustered in one branch,while others of DZ population clustered in one branch,indicating that DZ population had mutation due to long-term inbreeding.（3）Through the analysis of parasitic ability of two populations,showed that the parasitic efficiency of WC population decreased at the age of 5-6 days,but DZ population decreased at the age of 2-3 days.Both populations could parasitize continuously for two days,and there was no significant difference in the indexes of WC population parasitizing continuously for two days,but the adult number and parasitism rate of DZ population in the second day were significantly lower than those in the first day.There was no significant difference in the parasitic ability between the two populations to the pupae of different age,and all the parasitic indexes（except sex ratio）decreased with the increase of the host pupae age.The results showed that there were significant differences in parasitism ability at different parasitod ages and continuous parasitism ability between the two populations,and the parasitism of DZ population degenerated seriously.（4）The results showed there are many SSR,SNP and In Del sites in the transcriptome of T.brontispae,with high frequency,rich types and high polymorphism potential.The differentially expressed genes of the two populations involved major royal jelly protein,olfactory protein,cytochrome P450 and so on,which are closely related to the ontogeny,courtship and oviposition process of T.brontispae.（5）By observing the adult behavior of WC population,it was found that the average number of wasps per pupa was 23.51±9.08,and most of the pupae left 1-2 emergence holes（72%）in the 3rd-6thabdominal segments.For single parasitic,the average number of parasitoids per pupa were only 14.48±3.77.The mating time of T.brontispae was very short,multiple male parasitods may choose same famale to mate,and exhibit a competitive behavior,The duration of oviposition of the female parasitoids was concentrated in 16-20minutes,and all segments of the host pupa could be parasitized except two segments before and after. |
