4 July 2023

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

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)