| Grasshopper plague was one of the major natural disasters in Xinjiang, and caused extensive damage to grasslands every year.7 primary grasshoppers'choice for plant hosts was studied by field investigation and indoor feeding in different grasshopper breeding areas in Xinjiang. System evolution relationships of 7 species of grasshopper were analysed by molecular biological technology. The aim was to supply scientific assistant to classification system and molecule systematics of Acrididae and forecasting and predicting for grasshopper plagues.The main results were as follows:1.Results of 7 primary grasshoppers'choice for plant hosts showed that 3 species of Oedipodidae fed 14 plants among 4 families.The grasshoppers prefered to feeding Gramineae.3 species of Catantopinae fed 20 plants among 9 families.The grasshopper prefered to feeding Chenopodiaceae and Asteraceae Compositae. Gramineae was at least.Gomphocerus sibiricus of Gomphoceridae fed 12 plants among 5 families,and monocotyledon was 50%. Oedaleus decorus prefered to feeding Poa annua,and it didn't feed Capsella bursa-pastoris and Potentilla bifurca. Calliptamus italicus prefered to feeding Taraxacum mongolicum and Chenopodium album. Poa annua was hardly fed.G.sibiricus prefered to feeding Poa annua, Taraxacum mongolicum and Chenopodium album, and it didn't feed Potentilla bifurca.The species of Catantopinae prefered to chosing dicotyledon.Oedipodidae prefered to feeding monocotyledon,and Gomphoceridae liked dicotyledon and monocotyledon.According to the view of coevolution between insect and plant,Catantopinae was a primitive group among 3 families;Oedipodidae was the most advanced;Gomphoceridae might be the middle group.2.Random Amplified Polymorphic DNA(RAPD)markers were applied to analyze genetic relationships among 7 species of Catantopidae,Oedipodidae, Gomphoceridae.Genomic DNA of 7 species was amplified with 5 oligonucleotide primers respectively which were previously selected from 60 random primers.A total number of 49 clear and stable RAPD bands were observed.Nucleic acids extracted from 23 individuals among 3 species of Oedipodidae were amplified by using 10 primers.The agarose gel electrophoreses revealed 114 bands.225 bands of 26 grasshopper individuals among 4 populations of Catantopidae were revealed on the electropherogram, which were amplified by 17 primers.Percentages of polymorphic loci were:98% , 98.2% and 99.1% respectively.Nei's genetic distance showed that families> genus>species>populations.The cluster indicated that the individuals within a population were first clustered,then the different populations of the same species,and the species of the same genus,and the species among genera. One branch was that Epacromius coerulipes and Oedipoda caerulescens clustered,then O.decorus was clustered with them.Two C.italicus from Urumqi and Aletai were clustered for both were closely geographical populations,then clustered with Calliptamus barbarus, Calliptamus coelesyriendsis and G.sibiricus respectively,and finally they chustered with Oedipodidae.3.Fragments of mtDNA partial sequences of 7 species and the 3 species of Acridoidea were downloaded from the GenBank data library , and their homologus sequences were compared.There were 265 variable sites and 230 parsimony-informative sites in the nucleotides of the data. The percentage of A+T was 82.4% in the fragments.The variation rate of transversion was larger than transition. The molecular phylogenetic trees showed that the members of the same genus and family were first grouped together.Two closely geographical populations G.sibiricus from Hami and Aletai were not clustered.They produced inheritance polarization.The system evolution relationships of 5 families from original to evolution was Catantopidae,Acrididae, Gomphoceridae and Arcypteridae,Oedipodidae.It proved that system evolution relationship of 7 species of grasshopper was correct on the basis of the feeding habits study using molecular biology method again. |
