When Flowers Were New, This Ancient Beetle in Amber Pollinated Differently

The final meal of the false blister beetle pictured below ended on a traumatic note 105 million years ago. As it struggled to free its body from a gob of sticky tree sap, the grains of pollen clenched in its jaws tumbled free, rolling to their ultimate resting places around the beetle’s soon-to-be-still body. But one beetle’s bad day is a scientist’s gold mine: Researchers say the tableau in amber is proof of an entirely different form of prehistoric pollination. A report of the findings was published in the journal Current Biology.

Courtesy of David Peris (Departament de Ciències Agràries I del Medi Natural, Universitat Jaume, Castelló de la Plana, Spain)

 
The newly discovered beetle (Darwinylus marcosi) and its golden tomb date back to the mid-Mesozoic era. It was an exciting time to be alive—especially if you were a plant. The Earth was still mostly the dominion of non-flowering plants (gymnosperms), but the first flowering plants (angiosperms) had begun to arrive on the scene.

When we think of pollination today, we generally think of angiosperms, with their oh-so-subtle pistils and stamens gyrating in the breeze or quivering under the antennae of a honeybee. Gymnosperm reproduction is a rougher affair, as trees like pines and gingkos drop hard cones stuffed with spores. But it wasn’t always that way.

Recent discoveries like the unfortunate beetle shown above suggest that gymnosperms’ sex lives used to be much more varied. They had no fewer than four different demographics of non-plant partners. Moths, scorpionflies, and lacewings plunged their long, needle-like snoots deep into pinecone crevices and sucked out drops of liquid pollen. Other flies used sponge-like mouthparts to soak pollen up. Little bugs called thrips used their mouths like hole punchers, perforating pollen grains and draining the juice. And then there’s our unfortunate beetle friend, who likely used its jaw-like mouthparts to crack the little grains open and scarf up the good stuff within.

As flowering plants spread and took over, gymnosperm reproduction began to shift toward a more plant-centric model, eventually dumping its insect partners altogether. With no access to gymnosperm-based food, you’d think its former pollinators would die out. Many did. But the descendants of D. marcosi found a way to make it work: transferring their attention to flowering plants instead. Today, false blister beetles are an angiosperm-only family.

Paper co-author Conrad Labandeira is a paleobiologist at the Smithsonian Museum of Natural History. He says we could learn a lot from D. marcosi’s ability to move on after a pollination breakup. “Modern insect pollinators and their host plants may be facing similar conditions today,” he said in a statement, “and our understanding of this earlier transition may help us better grasp and comprehend the present situation."