A strange group of gymnosperms known as cycads may have been the first insect-pollinated plants on Earth, a new study published in Current Biology reports. While flowering plants are known for their unique relationship with pollinators, it was not always that way. To shed light on that ancient time period, researchers from the University of Bristol found fossils that show the earliest known evidence of the relationship between cycads and insects.
The team uncovered a 99-year-old boganiid beetle preserved in Burmese amber along with grains of cycad pollen. That insect is important because it had special adaptations — such as mandibular patches — to specifically transport cycad pollen. That then suggests its species may have been among the very first pollinators.
“Boganiid beetles have been ancient pollinators for cycads since the Age of Cycads and Dinosaurs,” said lead author Chenyang Cai, a researcher at the University of Bristol, according to Phys.org. “Our find indicates a probable ancient origin of beetle pollination of cycads at least in the Early Jurassic, long before angiosperm dominance and the radiation of flowering-plant pollinators, such as bees, later in the Cretaceous.” After finding the fossil the team cut and polished the amber so they could analyze it under a microscope. That revealed tiny cycad pollen grains.
From there, the team ran an extensive phylogenetic analysis to look at the beetle’s family tree. Such study showed the fossilized insect belonged to a sister group to the extant Australian Paracucujus, which pollinates the relic cycad Macrozamia riedlei.
As a result, it is likely that the discovery is from the first beetle-cycad relationship. The finding also suggests that there could be other pollinators in the fossil record waiting to be discovered. “The find of such an exceptionally well-preserved fossil beetle is surprising,” Cai told Gizmodo. “This is the first record of the family Boganiidae in the Cretaceous.”