LIFE × EVOLUTION

Colonies That Act as One Animal

~200 to 100 million years ago

Phanerozoic · Mesozoic · Jurassic

Insects that give up reproducing to raise their sisters, in colonies that behave like a single body. It happened in termites first, then independently in ants, bees and wasps. Ants preserved in hundred-million-year-old amber already carry the antennal organs used to smell an alarm and to tell a nestmate from a stranger, which are the two signals a colony cannot work without.

Why it matters

Reading their genomes shows how fast it was built. The three kinds of gene under the strongest selection as the main ant lineage appears govern caste differences, worker sterility and queen longevity, which is to say exactly the three things eusociality requires. The whole molecular foundation seems to have been laid in under twenty million years.

Dating & uncertainty

Termite eusociality is dated to around 200 million years ago by combining fossils and molecular clocks; ants appear later, and amber specimens of 100 million years ago already carry the antennal organs used for colony recognition.

Sources

1. Jouault et al. (2021), Systematic Entomology · Revising dating estimates and the antiquity of eusociality in termites
2. Romiguier et al. (2022), Current Biology · Ant phylogenomics reveals a natural selection hotspot preceding the origin of complex eusociality
3. Taniguchi et al. (2024), Science Advances · Sensory evidence for complex communication and advanced sociality in early ants

Earth history as one day

22:56:331 h 3 min before midnight

if Earth’s 4.54 billion years were compressed into a single day