Cretaceous generalist pollen feeders: early exploitation of plant resources by opilioacarid mites (Acari, Opilioacarida)

The evolutionary history of plant-arthropod interactions is a cornerstone of terrestrial ecology, yet the role of non-insect groups in early trophic systems remains poorly understood. While herbivory is well-documented in the extant mites, their early dietary habits have remained elusive. Here we report three opilioacarid mites from the mid-Cretaceous Burmese amber preserved in close association with diverse pollen types, including gymnosperm pollen from cycadaleans and Erdtmanithecales, and Chloranthaceae angiosperm pollen. The three mites represent distinct morphotypes yet co-occur with phylogenetically disparate pollen, indicating a possible generalist pollen-feeding strategy. Exceptional preservation of mouthpart structures supports a potential functional model in which pollen grains were grasped, mechanically ruptured, and ingested. This discovery implies the earliest evidence of pollen-feeding in arachnids, revealing a striking evolutionary stasis in opilioacarid ecology spanning nearly 100 million years. It highlights mites’ role in early plant-arthropod trophic networks, with shifts toward angiosperm hosts paralleling those in insects.