Insects in the Pleistocene Epoch

Pleistocene Epoch

• The Pleistocene epoch started 1.8 million years ago and lasted until about 10,000 years ago. Known as the "Great Ice Age," the Pleistocene ended as the last glaciers retreated in response to warming temperatures. Insect species that were living in unglaciated regions remained the same as those of the earlier Pliocene epoch. Many extant, or living insect species of the modern era, appear to be identical to their Pleistocene fossil counterparts. As is the case today, beetles dominated Pleistocene insect fauna.

Paleoclimatology

• Paleoentomologists study the fossilized remains of Pleistocene epoch insect populations to reconstruct the paleoclimate. The climate changed dramatically during the Pleistocene epoch with cold glaciated periods interspersed with warmer interglacials. Some Pleistocene insects species such as beetles, bees and ants had precise constraints on the temperature range they inhabited. Thermophilic, or heat-loving insects indicate rising temperatures, while the presence of alpine or tundra species correlates with falling temperatures. Changes in thermal environments and fluctuating microclimates can be mapped out by studying insect fossils.

Paleoecology

• Paleontologists have learned much about Pleistocene biomes, biota and ecosystems by studying well-preserved, precisely-dated insect fossils. Certain beetle species have restricted habitat requirements. Bark beetles will live only on certain types of trees, while dung beetle species are associated with the dung of specific animal species. The presence of carnivorous beetles implies the existence of spiders and flies as food sources. Flying pollinator insects have mouth parts and body brushes adapted to specific plant species.

Fossilization

• Pleistocene fossil insects are preserved by several geological processes. Many insects and insect parts are found in the asphalt deposits and tar pits of California. Peat bogs and lenses of organic material in gravel pits often contain Pleistocene insect remains. Insects trapped in sticky tree sap that solidified into amber include centipedes, walking sticks, termites, praying mantises, crickets, moths, flies, ants and other insects commonly found in the modern Holocene epoch.