Figure 1. Diagrams comparing original food web models and their two-mode version.

(A) the cascade model: each species (represented as an inverted triangle) is assigned a random value being placed along an axis. A given species i (gray) potentially interacts with those species whose values are less than the value assigned to i (as indicated by arrows); (B) the cascade model for two-mode networks: species that pertain to different sets (e.g. plants and animals) are randomly placed along two separate axes. The upper axis represents the axis of consumers. Therefore a given species i in the upper axis potentially interacts with those species in the lower axis whose values are lower than the value assigned to i. (C) The niche model: Each species is assigned a random value n_i and consume all species within a range of niche values r_i. (D) The niche model for two-mode networks: species that pertain to different sets (e.g. plants and animals) are placed along two separate axes according to their n_i. Each species in the upper axis consume all species in the lower axis that fall within a range of niche values r_i.