| The peach fruit moth(PFM)Carposina sasakii Matsumura(Lepidoptera:Carposinidae),is one of the most severe fruit moths in China.This moth is widely distributed in every province of China,except for Tibet.PFM often feed on varies of host plants,many of which are important economically valuable fruit trees such as apple,pear,jujube,apricot and the other more than 10 species.The PFM larva prefer to cause damages of the host tree by boring into and feeding on the fruits,and they are reproductive 1-3generations per year.Although there are some differences in the fruiting period of different host plants in the same area,the harm of PFM can last from June to October.Limited by the host plants,this insect may transfer damage among orchards of different host plant species,which is not clear at present.In this study,in order to determine whether there is a phenomenon of cross-garden transfer of PFM,the rule of growth and decline and diapause rate of this insect on different host plants in the field were studied,the flight ability of individuals feeding on different host plants was measured,and the genetic differentiation and kinship of different host fruit orchards were studied using the simplified genome sequencing technology.In addition,the intestinal bacteria of PFM from different host orchards were also studied in order to commit to the green prevention and control of this pest.The main findings are as follows:1.Growth and decline rule and diapause rate of PFM on different host orchardsThe population number of male adults in apricot,apple,begonia and hawthorn orchards was monitored from May to September using sexual attractants,the results show that the growth and decline of the adults of PFM on different host plants are basically the same.The first batch of male adults was attracted in late May until mid-September.Among them,the male adults could still be monitored in the apricot orchard after the apricot fruit was picked in mid-July,which may be transferred across other orchards or the emergence of non-diapause individuals.We brought the fruits of different host plants in the field back indoors to observe the number of larvae that de-fruited.The average number of insects per fruit on apples was the highest,up to 1.66,followed by begonia(0.84),the average number of insects per fruit on jujube was 0.74,and the smallest was 0.08 on apricot.Observation of the diapause rate of the above larvae found that,in apricot orchards,the diapause rate was51.52% in mid-July;in apple orchards,the diapause rate was 45.99 % in July and gradually rises to 94.74% in September;the corresponding diapause rate in begonia orchard was44.44% in early August and reached more than 90% from mid-August to early September.It showed that after the harvest of apricot fruit,the de-fruit PFM did not completely develpoed into the diapause state,and the emerged adults can transferred to other orchards for harm.According to the growth and decline rule of PFM in field and the observed diapause rate,it can be found that although the phenology of the host plants is different,there are adults of PFM in different host orchards from June to September,so there is a highly possibility of cross-orchards transfer for this moth.2.Flight ability of individuals feeding on different host plantsIn order to clarify the flight ability of PFM feeding on different host plants,the flight ability of male and female adults feeding on begonia,apple and apricot was measured using flying mill device.Four flight parameters,including individual flight distance,flight time,average flight speed and maximum flight speed,were compared across individuals in male and female as well as the same sex.The results show that in the 12-hour flight test,the longest flying distance is 24.54 km,the longest flight time is close to 12 h,and the highest proportion of individuals flying time is 11-12 h,occupying about 36.98%,and the maximum flight speed is 5.88 km/h,indicating that PFM has a strong flying ability.The four flight parameters of females are higher than those of males feeding on the same host tree,there are significant differences of the average flight distance among female and male adults feeding on the same apple(female: 15.06 ± 1.17 km,male:11.69 ± 1.26 km,P=0.034)or begonia(female:13.11 ± 0.91 km,male: 9.07 ± 1.22 km,P = 0.013)host.The flight ability for both female and male feeding on apple are higher than those corresponding sex adults feeding on another three hosts.Among them,the average flight distance of the female feeding on apple is significantly higher than those females feeding on apricot(female: 11.77 ± 1.33 km,P = 0.045),average flight speed and maximum flight speed are significantly higher than individuals feeding on another two host.While there are no significantly differences on the flight parameters across the males feeding on different host plants.Hence,PFM has strong flying ability and transfer ability,which provides evidence for the transfer phenomenon between different orchards.3.Genetic differentiation and kinship of PFM from different host fruit orchardsIn order to clarify whether there is effective transfer between different host orchards,435 populations from 22 populations collected from adjacent orchards of different host plant species are used to develop SNP molecular markers by double enzyme digestion and simplified genome sequencing technology.Populations genetic diversity,genetic differentiation and genetic relationship were also analyzed.The results display that the value for genetic differentiation between different host orchards are small,the maximum FST value was 0.0118,and the maximum FST value among different generations in the same orchard was 0.0085,which indicated that there was no significant host-related genetic differentiation of different host orchard population.Four pairs of individuals in different orchards were found to be genetic-related,which indicated that there was a phenomenon of cross transfer in different orchards.4.Intestinal bacteria of PFM from different host orchardsIntestinal microorganisms play an important role in the growth and development of insects,and are easily affected by the environment.Therefore,we studied the intestinal bacteria of PFM in two apple orchards and two pear orchards,and found that the intestinal bacteria are mainly Proteobacteria and Firmicutes at the level of phylum;at the level of genus,it is mainly consisted of Wolbachia,Pseudomonas,Gluconobacter,Acetobacter,Pantoea and so on.Among them,Wolbachia is the most abundant endosymbiont.In the Alph analysis,there are both obviously differences in community richness(Pace=0.0007,Pchao=0.0069)and diversity(Pshannon=0.0209,Psimpson=0.0095,Ppd=0.0395)among the intestinal bacteria of two populations of PFM feeding on pear,while there is only obviously difference in community richness(Pace=0.0017,Pchao=0.0490)among the apple-feeding PFM.In the Beta analysis,when the host is divided into apples and pears,PC1 = 53.37%,PC2 = 26.53%,R = 0.1218,P = 0.05,and when divided into four groups according to different host orchards,R = 0.1934,P = 0.02.In addition,the environmental signal process,metabolism,genetic information processing and cell process are mainly annotated in the functional prediction analysis.The results showed that the host plants and habitats had significant effects on the intestinal bacteria of PFM. |
PDF Full Text Request