Peppered Moth
Biston betularia
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The textbook example of evolution watched happening — and the story ran through Britain's industrial towns.
A moth speckled black on white, patterned to disappear against lichen-covered bark. A wholly black form, carbonaria, also occurs. Peppered moths are common in gardens, woodland and hedgerow around Dumfries and come readily to light. The species is probably the most famous insect in evolutionary biology.
Behaviour
As industrial soot killed lichens and blackened bark through the nineteenth century, the rare black form became far better camouflaged, and it rose from near-absence to dominate populations in polluted areas — then declined again after clean air legislation as pale bark returned. It is one of the best-documented cases of natural selection observed within human timescales. Caterpillars are remarkable twig mimics.
When to see it
Quick facts
- Family
- Geometer moths (Geometridae)
- Wingspan
- 4.5–6 cm
- Status
- Native; common and widespread
Photo by Cyndy Sims Parr, CC BY-SA 2.0, via Wikimedia Commons