Most of us learned about butterfly metamorphosis as a kid — a wriggly caterpillar molts its skin to form a tough chrysalis and emerges as a beautiful butterfly.
Most of us learned about butterfly metamorphosis as a kid — a wriggly caterpillar molts its skin to form a tough chrysalis and emerges as a beautiful butterfly. But how exactly do chrysalises stay anchored as the butterfly brews within? Research published in ACS Biomaterials Science & Engineering shows that, despite their silks being weak and thin on their own, caterpillars can expertly spin them into chrysalis support structures resembling hook-and-loop fasteners and multi-strand safety tethers.
Silk is a natural protein-based fiber that’s commonly associated with silkworms, but it’s also produced by other insects, including butterflies. In their caterpillar stage, butterflies use silk for spinning tethers to protect themselves from falls, tying up leaf bundles to hide in and weaving little silk carpets to latch onto while undergoing metamorphosis. When forming a chrysalis, caterpillars use a special arm-like structure called a cremaster that can grab this silk carpet and secure its chrysalis to a branch. Some species of butterflies go a step further and spin a special seatbelt around their thorax for extra security. But how strong is that silk, and what kind of structures make up these seatbelts and silk carpets? Qingyou Xia, Zhaoming Dong and colleagues raised some caterpillars and found out.
Read more at American Chemical Society
Image: Caterpillars spin silky carpets and seatbelt-like structures to protect themselves during metamorphosis. (Credit: Adapted from ACS Biomaterials Science & Engineering, 2024, DOI:10.1021/acsbiomaterials.4c00237)
