Figure 1.

Food-web motifs. When neglecting cannibalism, there are 13 unique food-web motifs composed of three species (Milo et al. 2002). To simplify our analysis and presentation, we separate the 13 motifs into two groups: (a) motifs S1–S5 that include only single links and (b) motifs D1–D8 that include double links (mutual predation). (c) A simple food web. (d) If we search the food web in (c) for food-web motifs, we find two instances of motif S1 and one instance of motif S2. Note that enumeration of food-web motifs counts separately all connected species triplets.