Aggregation dynamics of terrestrial isopods under extended Vicsek model

Terrestrial isopods exhibit a diverse range of behaviors, such as rapid escape responses and aggregation patterns. Their reactions to stimuli like artificial light, humidity, vibration, heat, and predation stress have been studied, yet the variations in these responses depend on the species and their specific ecological habitats.

The Vicsek model, a popular tool for examining collective behavior, has been modified to represent various biological processes. In this study, researchers exposed the terrestrial isopod Porcellionides pruinosus to varying combinations of vibration and light stimuli within a circular enclosure. The findings were then used to refine the Vicsek model to incorporate aggregation dynamics and speed variability.

By incorporating local group size and proximity to the enclosure's edge into the model, it was observed that the simultaneous presence of light and vibration led to increased isopod speeds compared to either stimulus alone. Moreover, the speed recovery of the isopods was delayed when they were subjected to the combined stimuli. Surprisingly, the traditional Vicsek model only accurately forecasted the isopods' movements within a few seconds after the onset of stimuli, highlighting the collective nature of their short-term movements.

However, when simulating swarms using the extended Vicsek model, the results aligned with the mean square displacement of the isopods tracked experimentally over extended periods, and this agreement varied depending on the stimuli. This improved version of the Vicsek model offers a valuable framework for investigating the effects of multiple stimuli on the collective and aggregation behavior of terrestrial invertebrates, ultimately providing a more comprehensive understanding of the diversity in their responses, which is crucial for comprehending the ecological roles these creatures play.