IDUKKI : In the rain-soaked forests of the Western Ghats, where mud, moisture and decaying leaves dominate the undergrowth, a small, slow-moving creature is revealing big scientific secrets.
The green pill millipede, Arthrosphaera lutescens — often seen carpeting the ground — has now been found to possess a self-cleaning ability that keeps its surface glossy despite living in grimy, humid conditions.
A recent study, led by Ajayakumar A P, of the division of biomaterial science at Pattambi Sree Neelakanta Government Sanskrit College, and published in the journal Scientific Data, has uncovered how this millipede achieves this feat.
While the research was conducted on specimens from the Nelliampathy Hills, scientists believe that similar pill millipede species found across the Western Ghats are likely to exhibit comparable features.
Using advanced techniques, including atomic force microscopy (AFM), the researchers zoomed into the millipede’s exoskeleton at a nanoscale level. What they found was a complex surface filled with microscopic “peaks and valleys”.
This uneven structure, along with tiny hair-like projections and a water-repellent coating, allows water droplets to bead up and roll off easily, thereby removing dirt particles and microbes.
The mechanism closely resembles the well-known “lotus effect”, where surfaces naturally clean themselves.
“The exoskeleton acts like a highly evolved natural system that resists contamination even in muddy conditions,” said Ajayakumar. “Its micro- and nanoscale structure helps water roll off, taking dirt along with it.”
The millipede’s shell is also tough and mineral-rich, making it both lightweight and strong. “These structural features and composition offer great potential for developing self-cleaning and water-resistant materials,” he added.
Although millipedes have been studied earlier for their behaviour, ecology and general body composition, detailed research focusing specifically on the structure and properties of their outer shell has been limited.
This study is one of the first to closely examine the exoskeleton of this species in such depth, combining multiple advanced techniques to understand how its surface, composition and strength work together.
The research also brings attention to lesser-explored aspects such as the shell’s mineral composition and mechanical strength. The presence of elements like calcium contributes to a structure that is durable and efficient, allowing the millipede to withstand external pressure without added weight.