A molecular phylogeny of Glaphyridae (Coleoptera: Scarabaeoidea): evolution of pollination and association with ‘Poppy guild’ flowers

Abstract

Among Scarabaeoidea, pollen feeding occurs in two major lineages, pleurostict Scarabaeidae and Glaphyridae. Here we infer for the first time the phylogeny of the scarabaeoid lineage Glaphyridae (Coleoptera) based on molecular data using partial gene sequences for 28S rRNA, cytochrome oxidase I (cox1) and 16S rRNA (rrnL) for 41 species. Based on the resulting tree topology, we inferred the timing of the origin of pollination and of their coevolution with different flower host taxa, with particular focus on the prominent red-coloured ‘poppy guild’ flowers. All genera of Glaphyridae that were sampled with multiple species were recovered as monophyletic. According to this analysis, the origin of Glaphyridae was around 140 Ma, while crown group divergence was dated to have occurred c. 112 Ma. Pollen feeding originated in Glaphyridae only once and much later than in other important pollinator groups, between 97 and 67 Ma. According to the reconstruction of ancestral feeding traits, Asteraceae (Cicharioidae) were the first hosts of Glaphyridae. Presumably, a further adaptive radiation was triggered by feeding on and pollination of red flowers (poppy guild) which arose at a later stage. It occurred for the first time between 30 and 40 Ma, whereby the clades that use red Ranunculaceae (Pygopleurus spp.) are older than clades using exclusively red Papaveraceae (Eulasia spp.) (25–30 Ma). The rather young age of red Ranunculaceae would imply that Pygopleurus species only subsequently used red Ranunculus species as flower hosts, and that a broad parallel host shift probably from red Papaver spp. to red Ranunculus asiaticus has occurred rather recently.