Plant-eating insects are the most diverse group of multicellular organisms on Earth. The most discussed drivers of their inordinate taxonomic and functional diversity are high niche availability associated with the diversity of host plants and dense niche packing due to host partitioning among herbivores. However, the relative contributions of these two factors to dynamics in the diversity of herbivores throughout Earth’s history remained unresolved. Using fossil data on herbivore-induced leaf damage from across the Cenozoic, paleontologists from the Hessian State Museum Darmstadt and the Senckenberg Biodiversity and Climate Research Center Frankfurt now show that the diversity of plant-eating insects evolved over the past 66 million years primarily through the shared use of food plants.
“Herbivorous insects are the most diverse group of multicellular organisms on Earth,” said Dr. Jörg Albrecht, a researcher at the Senckenberg Biodiversity and Climate Research Center.
“The variety of their mouthparts and feeding modes also testify to a high degree of diversity: for example, there are caterpillars or beetles that chew on leaves with their powerful jaw-like mouthparts, bugs and aphids that pierce plants to get at their sap, or animals that stimulate plants to form galls — an excessive tissue growth — in which they can develop and feed protected from enemies.”
“The feeding traces of such insects are also clearly visible on fossil leaves,” he added.
“They can help us to identify the factors that led to the enormous diversity of herbivorous insects.”
In their research, the authors classified 47,064 fossil leaves of 436 plant species from 16 sites in Central Europe, Iceland, and Norway.
“The fossils we studied cover nearly the entire Cenozoic era, i.e., the period between 66 and two million years before present,”
“Moreover, the fossilized leaves originate from a variety of climates — from subtropical to oceanic to humid…
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