Phylogeny of true ladybird beetles (Coccinellidae: Coccinellini) reveals pervasive convergent evolution and a rapid Cenozoic radiation

Abstract

AbstractCoccinellini, the ‘true ladybirds’, is a large, cosmopolitan tribe of lady beetles with immense variability in colour and form that include many commonly recognized species and major biocontrol agents, as well as some ubiquitous invasive species. In this study, we performed phylogenetic analyses of molecular and morphological data. For the molecular analysis, we gathered DNA sequence data from 164 species in 57 genera (and outgroups) from five nuclear genes [CAD (two fragments), TOPO, WGL, 3059fin] and one mitochondrial (COI) gene. The morphological analyses comprised 301 terminals and 61 discrete characters that were analysed by parsimony (MP). Our phylogenetic analyses indicate a monophyletic Coccinellini (former Coccinellinae) containing previously recognized tribes [Coccinellini, Discotomini, Halyziini, Singhikaliini and Tytthaspidini (incl. Bulaeini)]. Coccinellini is further divided into four main clades as follows: the Coccinella group (Clade A; incl. former Tytthaspidini), the Cycloneda group (Clade B), the Hippodamia group (Clade C) and the Synonycha group (Clade D; incl. former Halyziini, Singhikaliini and Discotomini). The phylogenetic relationships between them are: (A, (B, (C, D))). Our analyses also indicate that several currently recognized genera of Coccinellini are para‐ or polyphyletic. Based on our phylogenetic results, new generic groups are defined for Coccinellini, and new generic amendments are proposed as follows: Micraspis Chevrolat sensu n. (Oriental and Australian species), Microcaria Crotch sensu n. (=Bothrocalvia Crotch) (incl. Coelophora Mulsant species) and Phrynocaria Timberlake sensu n. (incl. Coelophora species). Further possible synonyms are discussed, for example, Coccinella Linnaeus (incl. Lioadalia Crotch), Psyllobora Chevrolat (including Oxytella Weise) and Xanthadalia Crotch (incl. Declivitata Fürsch and the African species of Micraspis). The large Clade D, the Synonycha group, with 26 predominant Old World genera, contains the two notable, large and non monophyletic genera Calvia Mulsant and Coelophora that confound the relationships throughout the clade. Additionally, we performed ancestral state reconstruction of selected morphological characters traditionally used in the classification of this group, revealing their homoplastic nature. We also found that the traditional synapomorphy of the tribe, that is, female colleterial glands, closely resemble structures used in symbiotic relationships in other beetles. We used the results of our phylogenetic inferences to estimate divergence times of the tribe and major clades of Coccinellini.