Sept. 17 (UPI) -- The discovery of more than two dozen amber fossils has offered scientists new insights into the lacewing populations that pollinated plants during the Mesozoic.
Scientists know pollinators influenced the evolution of early angiosperms, or flowering plants. But evidence of early pollinator-plant relationships among pre-angiosperm plants is harder to come by.
In a paper published this week in the journal Nature Communications, researchers from the Chinese Academy of Science described the discovery of 27 amber fossils containing the remains of kalligrammatid lacewings.
The Kalligrammatidae family of insects -- the "butterflies of the Jurassic" -- were the largest Mesozoic insects with siphoning mouthparts. In the late 19th century, Charles Darwin first identified a correlation between insects' proboscises and the length of floral tubes.
Darwin argued the relationship between mouthpieces and flower tubes proved pollinators and flowers co-evolved to form pollination niches.
Analysis of the newly discovered amber fossils, dating from between 165 and 95 million years ago, revealed a diversity of a proboscis lengths.
"The high diversity of kalligrammatids and large variation in proboscis length strongly suggest diverse plant hosts with different floral tube lengths," researchers wrote. "Therefore, pollination niche partitioning may have been present among some Mesozoic insects."
The formation of pollination niches, scientists suggest, would have allowed for more efficient pollination. Pollination mutualism would have also encouraged greater diversity among pollination insects and pollinator-dependent plants.
Scientists surmise pollination niche partitioning also contributed to the sudden downfall of kalligrammatid lacewings. Because the insects likely developed pollination relationships with mostly gymnosperms, lacewings died out as gymnosperm diversity declined during the late Cretaceous period.