Research On The Systematics Of The Tribe Chilocorini Mulsant Of The World (Coleoptera: Coccinellidae)

The tribe Chilocorini Mulsant belongs to family Coccinellidae of order Coleoptera.Majority of the species in this group are predators of scale insects,while a few species can also prey on aphids,and whitefly nymphs.It is a kind of important natural enemies and one of the most important groups of ladybeetles as biocontrol agents.To date,there is still enormous controversy about the relationship between Chilocorini and the other tribe of Coccinellidae.A comprehensive revision of phylogenetic relationship and classification within Chilocorini is also rarely known.In this study phylogenetic relationship of Chilocorini was constructed on the basis of five gene fragments(four nuclear fragments: two fragments of CAD,TOP and Wingless,and one mitochondrial gene fragment: COI)and 127 morphological characteristics.For the construction of molecular phylogenetic tree,Maximum likelihood and Bayesian Inference were implemented in RaxML and MrBayes software,respectively.The Maximum Parsimony was implemented in TNT software basing on morphological data to construct phylogenetic tree.We also tried to combine the molecular and morphological data in Mr Bayes for a comprehensive analysis of the relationship between existing genera(26 genera)of Chilocorini.The recovered phylogenies were congruent and revealed that the tribe Chilocorini is a monophyletic.The tribe Plotinini was for the first time identified as a sister group of Chilocorini.Chilocorus Leach,Anisorcus Crotch,Phaenochilus Weise,Egius Mulsant and Simmondsius Ahmad et Ghani formed a big clade with close relationships,while Chilcorus,Anisorcus,Phaenochilus are paraphyletic.Endochilus formed a sister group with Chapinaria,but its position in the Chilocorini is unclear.The relationship of the genus Sicardiana in Chilocorini was also ambigouius.The monophyly of each genus in Exochomus group is confirmed,and the six genera(Axion Mulsant,Arawana Leng,Harpasus Mulsant,Cladis Mulsant,Curinus Mulsant,Zagreus Mulsant)are mainly distributed in the Nearctic and Neotropical showed closer relationships.Australian endemic genera: Halmus Mulsant,Hypoceras Chapuis,Orcus Mulsant,Trichorcus Blackburn are similar in the body shape,but they don't show close relationships,in which Trichorcus + Halmus + Hypoceras form a sister group,while Orcus is confirmed as a sister group with Chujochilus.For better understanding the morphological relationship between the genera of Chilocorini,the above 127 morphological characters were mapped to the Bayesian inference tree in WinClada software.A scanning electron microscope was used to capture important identification characters of each genus.The worldwide Chilocorini was comprehensively revised in a clear phylogeny and morphological characters.Twenty genera were contained in the new classification,in which six new synonymy were proposed and one genus was describled as new to science.The following new synonyms are proposed: Axion Mulsant,1850(=Arawana Leng,1920 syn.nov.;=Harpasus Mulsant,1850 syn.nov.);Chilocorus Leach,1815(=Anisorcus Crotch,1874 syn.nov.;=Egius Mulsant,1850 syn.nov.;=Phaenochilus Weise,1895 syn.nov.;=Simmondsius Ahmad & Ghani,1966 syn.nov.);Renius,gen.nov..Fourty three species belonging to 9 different genera were documented in Chinese fauna in the new classification.Phaenochilus albusolomus Li & Wang,2017 and Phaenochilus metasternalis Miyatake,1970 were transferred to the genus Chilocorus(comb.nov.).When we studied the Chinese Chilocorini,a new genus was recorded from China,eight new species(five of which were published)and 3 new Chinese record species were found which are as follows:1 New Chinese record genus: Brumus octosignatus(Gebler,1830);8 New species: Chilocorus nigricaeruleus sp.nov.;Chilocorus strenotubus sp.nov.;Renius cornutus sp.nov.;Chilocorus albusolomus(Li & Wang,2017);Xanthocorus nigrosuturarius Li & Ren,2015;Xanthocorus mucronatus Li & Ren,2015;Exochomus rubistictus Li & Ren 2015;Parexochomus oligotrichus Li & Ren 2015.4 New Chinese record species: Brumus octosignatus(Gebler,1830);Priscibrumus disjunctus Canepari,1997;Priscibrumus uropygialis(Mulsant,1853);Parexochomus semenowi Weise,1887.