Geological Eras of Prehistoric Insects
Insect evolution spans more than 400 million years, across some of the most dramatic changes in Earth's climate, atmosphere, and ecosystems. The pages in this section cover each major geological period during which insects lived and evolved, from their first appearance in the Devonian through the end of the Cretaceous. Each era page describes the environmental conditions of the time, the major groups of insects that lived during that period, and the key evolutionary developments that occurred.
For context, insects first appear in the fossil record during the Devonian, but the record becomes rich during the Carboniferous, when coal-swamp forests created conditions that both favored giant insects and preserved many of them as fossils. The timeline below covers the Paleozoic and Mesozoic eras — the scope of this site ends at the K-Pg extinction event 66 million years ago, which marks the boundary between the age of dinosaurs and the modern world.
Timeline
| Era | Time Range | Key Developments |
|---|---|---|
| Devonian | 419–359 Ma | First insects appear; wingless hexapods |
| Carboniferous | 359–299 Ma | Giant insects; first flight; oxygen peak |
| Permian | 299–252 Ma | Rapid diversification; first complete metamorphosis; Great Dying |
| Triassic | 252–201 Ma | Post-extinction recovery; early social insects |
| Jurassic | 201–145 Ma | Beetle diversification; plant co-evolution |
| Cretaceous | 145–66 Ma | Pollinators emerge; amber preservation; K-Pg extinction |
- Mass Extinctions and Insects — how insects survived (and didn't survive) the Big Five extinction events
- From Ancient to Modern — tracing lineages from prehistoric to living insect families