Most of our human food comes from quilt plants (flowering plants), and more than 90% of quilt plants require insect pollination. When did such an important pollination begin to occur on Earth? Researchers at the Nanjing Institute of Geology and Paleontology of the Chinese Academy of Sciences found the flea beetle, which carried large amounts of pollen 100 million years ago, in myanmar amber, the earliest direct evidence of the media-borne pollination of the quilt plant. The study was published online in the Proceedings of the National Academy of Sciences.
Flower fleas and pollen specimens, nanjing paleontological institute of the Chinese Academy of Sciences
Quilt plants (flowering plants) are the most abundant flora today. Fossil records show that quilt plants suddenly appeared in large numbers in the middle of the Cretaceous period. Darwin called this “abnormality” a “nasty mystery”. Many quilt plants pollinate through insects , which promote gene flow and form a high degree of diversity. Therefore, insect pollination is considered to be a key factor in the large eruption of quilt plants in the middle of the Cretaceous period. Although the species of insects and quilt plants in the mid-Cretaceous period have been abundant, direct evidence of quilt insect-borne pollination during this period has been lacking.
The team of researchers at the Nanjing Institute of Paleontology of the Chinese Academy of Sciences, who sat on the mid-Cretaceous (about 100 million years ago) in Burmese amber, was named the Burmese flower flea, and the team used high-resolution optical microscopes and microtomography (micro-CT) to analyze the body shape of the fleas and obtain high-precision 3D images. The amber flea’s body is flat and C-shaped, with the back foot extremely developed for jumping. This body type is ideal for moving over the corolla to efficiently touch and carry pollen. In addition, the jaw of the flea mouth piece has a large swelling, used to collect and take pollen particles.
Using laser confocal microscopes and high-octane optical microscopes, the team found that at least 62 pollen particles were preserved near the belly, wings and bodies of fleas and determined that the pollen was typical of three-groove pollen. Three-groove pollen refers to each pollen particle with three radiation arrangement of the groove, which is also an important identification characteristic of the true gemini leaf plant.
Taken together, they determined that the amber specimen showed the pollination behavior of the mid-Cretaceous flea beetle on quilt plants and revealed the insect-borne pollination mechanism of the early true gemini plants.
The earliest direct evidence of the pollination of quilted plant insects was the fossils of bees and pollen unearthed from the Messer fossil pit in Germany (about 48 million years ago). As a result, myanmar’s amber pollinator flea study advances this record by at least 50 million years and provides the only and earliest direct evidence of the Cretaceous period.