Wormlet Spreading Dynamics: Probing the Viscoelastic Fluid-like Behavior of Entangled Active Worm Droplets

California blackworms (Lumbriculus variegatus) are slender, polymer-like invertebrates that exhibit remarkable collective behavior, actively entangling themselves to form living worm blobs. These active soft-matter assemblies display viscoelastic fluid-like behavior. As an illustration, we study the deposition of these worm droplets in a solid flat surface resembling a classic sesile droplet. By varying the water content in the blob, we explore the impact on the shapes the flowing blobs take in free-surface configurations. Varying water to worm ratio changes the effective surface tension of the deposited wormlets and the respective droplet spreading dynamics. Both configurations are analyzed through a direct analogy with the behavior of an effective complex fluid. We quantified the spreading ratio and compared the spreading rate to the scaling prediction of Tanner's Law for non newtonian viscous fluids. Droplet deposition and spreading is widely studied across interdisciplinary domains, these insights could improve our understanding of the role activity and entanglement plays in flow dynamics of soft active entangled materials.