DNA-based Identification Of Sexual Dimorphism And Geographic Distribution Of Megaselia Rondani (Diptera:Phoridae) In Liaoning Province

Megaselia belongs to Diptera,Phoroidae,Metopininae,it is the largest genus of Phoroidae.So far,more than 1500 species have been known all over the word,exceed 60% of which are unisexual species.There are some problems on species identification,sexual dimorphism,phylogenetic reconstruction.but shorting of available morphological characters make it difficult to resolve these problems only using morphological methods.DNA-based identification systems can resolve these problems.This study based on the mitochondrial CO? gene and morphological characters to match male and female,and describe their morphological characters of Megaselia in Liaoning province.As the same time,we discussed the geographic distribution of Megaselia flies in Liaoning province.In MP tree and NJ tree,45 species including outgroups(5species)are grouped separately with good support(?96%??99%),in which 38 species(subspecies)of Megaselia matching male and female successfully.The base composition of Megaselia mtDNA CO?sequence is AT-rich,with 67.7% A+T and 32.3% G+C.It exhibited the bias mitochondrial bases of insect.40 species(subspecies)of Megaselia intra-specific divergence is 0.00-0.85% and inter-specific divergence is 6.93%-23.37%,which is similar to other groups,but a little higher.In MP tree and NJ tree,Diplonevra,Dohrniphora Phalacrotophora and Megaselia are not separated well,and the sequence divergence among genera have some overlap.This provides the molecular support of the paraphyly of Megaselia.In this paper,38 species(subspecies)of Megaselia are described,among them group?2 species,group 7 ? species,group 8 ? species,group 2 ? species,group ?1 species,group 14 ? species(subspecies),group 4 ? species;Among them 21 species have known,17 species have unknown.Found species mainly identification characters of Megaselia are supra-antennal bristles,anepisternum,notopleural bristles,scutellar bristles,pretarsus of fore leg,femur of hind leg,costal index,subcosta,Abdominal spiracle,terminalia,et al.Sexual dimorphism characters are antennae,scutellar bristles,wing,Abdominal spiracle,stretch mark of the abdomen back,et al.more than 500 phtotos were taken.Geographic distribution of Megaselia flies in Liaoning province was preliminary discussed.Fourteen cities of Liaoning province all have Megaselia flies.The number of species of Megaselia is at most in the eastern region,an least in the western region,central region between them.