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4 July 2023

4 July 2023 – Mother of Pearl, an Inspiration to Science

Mother of Pearl moth
Mother of Pearl (Patania ruralis)

Mother of Pearl (Patania ruralis) was another catch I’ve been waiting to see. This was a particularly beautiful and well-marked specimen: the photograph can’t do justice to the iridescence of its wings. The Mother of Pearl’s beauty is such that it almost appears as a tiny, nocturnal fairy: glinting in the moonlight, its flight pattern graceful and delicate.
But before the Mother of Pearl was a dainty ballerina, she was an accomplished gymnast! The larvae of Patania ruralis are marvels of natural bio-engineering, famous for their unique “rolling” locomotion. They’re one of only two creatures in the animal kingdom who use the extraordinary method of ‘ballistic rolling!’ (The other is a shrimp.) The caterpillar arches its back until it forms a circle and, using the momentum of its lower body, flips itself backwards. (See article from Scientific American with a remarkable video demonstration here!) The Mother of Pearl caterpillar’s rolling abilities allow it to travel at speeds of around 40 cm·s⁻¹, a whopping 40 times faster than its normal walking pace! Such a unique and effective locomotion method has inspired mechanical engineers to create robots (like this GoQBot) that employ the same techniques. Truly a remarkable creature to discover living on the nettles in the garden!

Post: Autumn Cortright (UPenn Intern)