Revisiting the phylogeny of the family Miridae (Heteroptera: Cimicomorpha), with updated insights into its origin and life history evolution.

ABSTRACT

Heteroptera is one of the most successfully adapted groups on Earth and can be observed in almost every environment. Within the evolution of heteropteran insects, Miridae show remarkable diversity (>11,700 spp.), accounting for a quarter of all Heteroptera. However, their phylogeny is still unclear, and no plausible theory for the driving force of their diversification has been established. In this work, we provide new suggestions for the phylogeny of Miridae using a larger dataset than previous studies. In addition, we suggest an alternative evolutionary history based on newly calibrated divergence dates for Miridae and its subordinate groups, and present probable factors of the family's success in terms of species diversity. The entire dataset comprises 16 outgroups and 188 ingroup taxa including all seven known subfamilies and 37 out of 45 known tribes. Each species is aligned as 3,577 bp with six molecular loci (COI, 16S rRNA, 18S rRNA, 28S rRNA D3 region, H2A, and H3A). Among the molecular markers, we are the first to test histone genes (H2A, H3A) in Miridae. Our results raise the following points about phylogenetic relationships i) The earliest group to diverge from Miridae was Monaloniini (Bryocorinae). ii) Bryocorinae and Cylapinae are polyphyletic, Deraeocorinae and Orthotylinae also rendered as non-monophyletic group. iii) Termatophylini and Coridromiini separated from Deraeocorinae and Orthotylinae respectively. iv) Four large tribes, Orthotylini, Phylini, Deraeocorini and Mirini are non-monophyletic. The results from our ancestral state reconstruction and divergence date estimation suggest the following i) Miridae first diverged during the Late Jurassic (approx. 163.4 Mya), and the divergence dates of most subfamilies and tribes overlap with angiosperm radiation, which perhaps synergized their diversification. ii) Ancestral reconstruction results for Miridae reveal it to be predominantly phytophagous and diverge to oligophagy mainly in plant-tissue habitats, which could have allowed the mirids to select optimal tactics as plant-dwellers. iii) The common ancestor of Miridae originated among plant-dwellers mainly on Eudicots, and that tendency was largely maintained, but sporadic host shifts also occurred.