Predators and Trophic Species

Most food webs in nature have proved to have a scale-free network topology where some species have a much larger number of dependencies and interactions than all the others. Because of this inherent structure, food webs suffer from the two main paradigms of scale-free networks:

– They are resilient to random failures (in this case to the deletion/extinction of species)
– They are sensible to the removal of most connected vertices/nodes (species)

The correlation between network hubs and species in food webs is held mostly by lower trophic species – functional groups that contain organisms that appear to eat and be eaten by the exact same species within a food web (Cohen and Briand 1984). These lower level species usually have a high number of links by feeding several species and are normally photosynthesizers or alike. In the opposite side are the predators, higher trophic species on the top of the food chain with a smaller number of interactions.

The next food web models are screenshots from Dr. Joseph Luczkovich’s Java Application developed at the Biology Department at East Carolina University. These models are extremely interesting, appealing and functional. One can select the different species and elements to analyze, compare their interactions and zoom extensively in and out of the digitally produced food web. For more information on Dr. Luczkovich’s Food Web Visualizations click here.


Copyright Dr. Joseph Luczkovich. For more information on Dr. Luczkovich’s Food Web Visualizations click here.


Copyright Dr. Joseph Luczkovich. For more information on Dr. Luczkovich’s Food Web Visualizations click here.


Copyright Dr. Joseph Luczkovich. For more information on Dr. Luczkovich’s Food Web Visualizations click here.


Copyright Dr. Joseph Luczkovich. For more information on Dr. Luczkovich’s Food Web Visualizations click here.


Copyright Dr. Joseph Luczkovich. For more information on Dr. Luczkovich’s Food Web Visualizations click here.

Pinnacles Food Web Model


Copyright USGS. This image shows the qualitative food web model for reef fishes of the Pinnacles Reef Tract constructed from stomach content analysis. Position on the food web model is based on relative proportion of pelagic prey (x axis) and trophic position (y axis).

Lake Erie


Copyright USGS. This image maps the food web of the west basin of Lake Erie as represented in the trophic transfer model.