Application Of DNA Barcoding And Life Table Techniques In The Related Studies Of Aphis Gossypii Or Parasitoids

Parasitoids play an important role in the biological control of Aphis gossypii Glover.The identification of parasitoids is the primary condition for the development and utilization of parasitoids.It is difficult for people who are not taxonomists to identify parasitoids,because parasitoids are small in shape,and identification requires professional classification knowledge.The DNA barcoding technology provides a powerful tool for the researchers.we collected parasitoids in the watermelon planting area of Daxing and Shunyi in Beijing for two consecutive years,and explored DNA barcoding identification of A.gossypii parasitoids based on the primary morphological classification.The effectiveness of barcode identification was analyzed by ABGD,NJ tree topological structure and genetic distance analysis.The results showed that DNA barcoding technology can be used to separate parasitoids at species level,and 3940 parasitoids were identified as 14 species belonging to 13 genera and 7 families.In addition,the effects of COI gene and 28S gene on the identification of parasitoids on A.gossypii were compared.It was found that the COI gene could distinguish the parasitoids species more accurately,while 28S?D2 region?sequence can be used as auxiliary.It is expected that there is a mismatch of the network database discovery,because the data source of the database is wide,and the accuracy and reliability of the identification are doubtful.On the other hand,it is suggested that some species should be treated with caution.It is best to distinguish them reliably by morphological and molecular fragments.In order to explore the biological characteristics of developmental duration and fecundity on A.gossypii with different hosts?watermelon and pumpkin?,and to further explore the parasitic effects of dominant species Binodoxys communis?Gahan?on A.gossypii.constructing the life tables of A.gossypii and using life table method to study the parasitic characteristics of B.communis,and get the related life table parameters of net reproduction rate?R₀?,mean generation time?T?,intrinsic rate?r_m?and finite rate of increase???.The results show that the R₀,T,r_m and?of A.gossypii on watermelon and zucchini were 59.57,9.87d,0.41,1.51 and 47.96,11.34d,0.34,1.41,respectively.The R₀ values and r_m values of A.gossypii on watermelon were higher than that of A.gossypii on zucchini,indicating that the population proliferation rate and development rate of A.gossypii on watermelon were higher than that of the A.gossypii on zucchini.Therefore,the A.gossypii was more suitable for the development and reproduction of watermelon than the zucchini.The eclosion success rate of Binodoxys communis parasitized A.gossypii was 62.18%,and the ratio of female to male is 1.30:1,which provides scientific basis for further development and utilization of this parasitoid.In the future,Explore the protection strategies of B.communis in watermelon sheds to bring its control potential.