Invisible Dust

London | Sunday 17 February
Pollution level: Moderate

The black Peppered Moth gives a flavor of air pollution

Kasia Molga, The Human Sensor Project, 2016
© Kasia Molga, The Human Sensor Project, 2016


The black Peppered Moth provides a fascinating case study of the indicators and effects of air pollution. The first black Peppered Moth was recorded in Manchester in 1848 and by 1895 98% of Peppered Moths in the city were black, why?

Peppered Moths are traditionally white with black speckles. This patterning provides the moth camouflage against lichen-covered tree trucks. A naturally occurring mutation causes some moths to have black wings. These so-called ‘malanic’ black Peppered Moths were less well camouflaged on the lichen as their peppered companions, meaning far fewer survived, or rather far more were eaten by birds and other predators.

In the nineteenth century it was noticed that it was the black variation of the Peppered Moth that was more common in towns and cities. Sooty air caused by air pollution had killed off lichens and blackened urban tree trunks and walls. The result: the black Peppered Moth came to outnumber the paler forms in towns and cities.

The blackened, polluted environment provided an ideal habitat for the black Peppered Moth to camouflage itself.  Due to the short life span of moths natural selection happens rapidly, causing this astonishing phenomenon to be perceptible over the course of less than 50 years.

Invisible Dust is working with digital artist Kasia Molga and scientist Professor Frank Kelly, as part of Manchester European City of Science, to create an exciting new project ‘Human Sensor’. Molga’s performers will wear the first capes that monitor air pollution, in Manchester in July 2016. While the Peppered moth changed its colours in response to air pollution though natural selection, Molga’s capes use innovative technology to alter colour in responds to local air pollution.


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