Is the grass greener on the other side? Phylogeny and biogeography of grass-feeding plant bugs of the genus Collaria Provancher (Hemiptera: Miridae: Mirinae)

Abstract

The grass-feeding plant bug genus Collaria contains important agricultural pest species responsible for significant economic damage to pasture crops in the New World. The genus belongs to Stenodemini (Miridae), with 21 valid species distributed in the Afrotropical, Nearctic, and Neotropical regions, an intriguing distribution for an apparently recently diversified clade associated with grasses. To investigate the evolutionary and biogeographical relationships of Collaria species, a morphological phylogenetic analysis was carried out. The phylogenetic analysis recovered Collaria as monophyletic, with Nabidomiris as its sister group. Within Collaria, two main clades were recovered, one composed exclusively by Afrotropical species, and another by Nearctic and Neotropical species, in addition to one Afrotropical species, C. royi. The biogeographic analysis, using a geographically explicit event model method (GEM), identified various geographic events, including vicariance, sympatry, and founder events. Given the recent diversification of Stenodemini lineages, alternative hypotheses to a Gondwanan origin are proposed. Among them, the vicariant pattern between the Neotropical and the Nearctic + Afrotropical clades is explained by geodispersal, and subsequent vicariance, through a series of large dry land extensions found in the South Atlantic 50 million years ago. The vicariant event between North America and Africa is explained by boreotropical migration, when Africa was connected to Eurasia during the Miocene. Further explanations within the African, Nearctic, and Neotropical clades are provided for the biogeographic patterns recovered. Our results help explain a complex and recent biogeographic history for an important grass-feeding group of plant bugs.