  We study a nonhierarchical tritrophic system, whose predator-prey
interactions are described by the rock-paper-scissors game rules. In our
stochastic simulations, individuals may move strategically towards the
direction with more conspecifics to form clumps instead of moving aimlessly on
the lattice. Considering that the conditioning to move gregariously depends on
the organism's physical and cognitive abilities, we introduce a maximum
distance an individual can perceive the environment and a minimum conditioning
level to perform the gregarious movement. We investigate the pattern formation
and compute the average size of the single-species spatial domains emerging
from the grouping behaviour. The results reveal that the defence tactic reduces
the predation risk significantly, being more profitable if individuals perceive
further distances, thus creating bigger groups. Our outcomes show that the
species with more conditioned organisms dominate the cyclic spatial game,
controlling most of the territory. On the other hand, the species with fewer
individuals ready to perform aggregation strategy gives its predator the chance
to fill the more significant fraction of the grid. The spatial interactions
assumed in our numerical experiments constitute a data set that may help
biologists and data scientists understand how local interactions influence
ecosystem dynamics.
