LIFE × EVOLUTION

Bees and Flowers

~123 to 100 million years ago

Phanerozoic · Mesozoic · Cretaceous

Wasps that fed their young on insects switched to feeding them on pollen, and became bees. It happened in western Gondwana, before the South Atlantic had opened, and at the moment the eudicots were spreading, the group that holds three quarters of all flowering plant species. Neither has managed without the other since.

Why it matters

About a third of what people eat depends on animal pollination, and most of that on bees. A dependency that old is not a habit but a structure: the flowers built to be visited and the insects built to visit them evolved into each other's shape, and neither can now be replaced quickly.

Dating & uncertaintyDisputed

Molecular clocks put the origin of bees near 123 Ma, with a range from 113 to 132 Ma; the oldest bee fossils are far younger, which is the usual mismatch between the two kinds of evidence. The date of the flowering plants themselves is the older half of the same argument, and Darwin's abominable mystery is not settled.

Sources

1. Cardinal & Danforth (2013), Proceedings of the Royal Society B · Bees diversified in the age of eudicots
2. Almeida et al. (2023), Current Biology · The evolutionary history of bees in time and space
3. van der Kooi & Ollerton (2020), Science · The origins of flowering plants and pollinators

Earth history as one day

23:20:5939 min 1 s before midnight

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