Figure 1.

Conceptual diagram depicting conditions of spatial complexity simulated in individual based models (IBMs). Columns: The spatial distribution of resources and organisms was modeled in two ways. (Left) Locations of resource particles and individual organisms changed randomly between time steps, resulting in a well-mixed model of uncorrelated changes in position. (Right) Aggregated resource particles remained largely fixed in position and only made slight movement under Brownian motion, resulting in a highly structured and spatially heterogeneous environment. Rows: Whether in a well-mixed or structured environment, individuals could change position under three modes of dispersal. (Top) Individuals could disperse passively (no active dispersal), relying entirely on either the well-mixed conditions or Brownian motion imposed by their environment. (Center) Individuals could actively disperse along a trajectory and change direction upon hitting a barrier or edge, in a “run and tumble” fashion. (Bottom) Most energetically expensive, individuals could actively disperse in a directed manner after sensing the presence of consumable resources, i.e., chemotaxis. In the modeling, each condition of resource distribution was compatible with all conditions of individual dispersal, resulting in 6 possible combinations.