The insects take longer than the plants
Fossil leaves record who was eating them, and the bite marks show herbivore communities took millions of years to rebuild.
- When
- —
- Duration
- 7 million years
- Known to
- ± 1 million years
- Era
- Paleocene, Cenozoic
Damage on fossil leaves — mines, galls, distinctive chew patterns — can be matched to the kinds of insects that made them, which turns leaf beds into a census of herbivores. Across the boundary in the Rocky Mountain interior the diversity of damage types collapses and then recovers far more slowly than plant diversity does, with specialised feeders such as leaf miners hit hardest and slowest to return. Specialists depend on particular hosts; when the hosts go, so do they, and rebuilding a tightly coupled relationship takes far longer than regrowing a forest.