Collective states of the nematode Turbatrix Aceti inside Viscous Fluids

Collective motion in microorganisms has emerged as a powerful model for studying emergent behaviors in active matter systems. Vinegar eels (Turbatrix Aceti) are nematodes that can synchronize their body oscillations and display collective swimming behaviors. While their motion in low viscosity fluids well studied, their behavior inside viscous fluids is a knowledge gap. This study aims to investigate how Vinegar eels collectively travel in oils. We find that the nematode form filaments inside oils, which propagate and branch, reminiscent of neuron connections. We study the different parameters of individual filaments, such as thickness, length, and velocity. We also analyzed the global geometric complexity by performing fractal analysis of the formed networks. Initial image analysis revealed that the nematode's ability to penetrate the oil-vinegar interface is dependent on pre-existing irregularities in the oil-vinegar interface, with the initial angle of these irregularities heavily influencing features of filaments. These results show that geometry of the water-oil interface is deterministic in predicting the collective motion of filaments in oil.