From figs to acorns: Early specialization and host shifts shaped the global radiation of Curculionini weevils (Coleoptera: Curculionidae)

Abstract Here, we present a phylogenetic analysis of Curculionini based on 84 ingroup species from seven genera; 19 fig‐associated species were newly sequenced for this study from material reared from approximately 110 fig trees representing 25 Ficus species, while the remaining 65 Curculionini species and all 61 outgroup taxa were obtained from previously published datasets on GenBank. Our analyses suggest that Curculionini originated in the early Palaeocene (ca. 65 Ma), with crown diversification beginning in the early Eocene, broadly coincident with the Eocene Climatic Optimum and the expansion of tropical Ficus (Moraceae). Although traditionally regarded as nut‐ and gall‐feeding beetles, our results indicate that fig feeding was likely the ancestral host association within the tribe. At least three independent host shifts subsequently occurred towards other rosalean fruits, insect galls and hard seeds of Fagaceae and Juglandaceae. These shifts are temporally concentrated from the late Eocene onward, coinciding with global climatic cooling and the expansion of temperate broad‐leaved forests. Biogeographic reconstruction supports an Afrotropical origin of Curculionini , followed by dispersal into the Oriental and western Palearctic regions. A single Beringian dispersal event gave rise to the Nearctic acorn‐weevil radiation. Our analyses further reveal extensive polyphyly within Curculio and demonstrate that current subtribal classifications do not reflect evolutionary history. Taken together, our results are consistent with the hypothesis that morphological and physiological preadaptations for exploiting concealed and chemically defended plant tissues, interacting with major Cenozoic Earth‐history events, shaped the global diversification of Curculionini.