A Lunar Thorn and the Biologist’s moth

Despite the rain my trap had some interesting species in it this morning.

This is a Lunar Thorn – a local species Britain. The adults are on the wing in May and June. Their caterpillars feed on the leaves of broad-leaved trees such as ash and blackthorn both of which occur in my garden.

This is the Peppered Moth – when I was taught O Level biology this species featured. This black and white colouration has evolved so that the moth can safely rest during the day on a tree trunk covered in lichen where it is then perfectly camouflaged.

However as a result of aerial pollution from the Industrial Revolution the lichens on trees, particularly in areas close to smokestack factories, were killed and the camouflage inherent in a black and white moth was lost. The Peppered Moth stood out like a sore thumb on a dark tree trunk. However a dark form of the Peppered Moth occurred in very low numbers and this colour form then became the dominant colour pattern as it once again gave the species the required camouflage to avoid predation.

Once levels of pollution (particularly sulphur dioxide) reduced the lichens were then able to grow on the tree trunks again and the black and white form of the Peppered Moth became the dominant one again.

This is the dark form of the Peppered Moth f. carbonaria

Photo with Wikimedia Commons copyright  Olaf Leillinger

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