Network analyses reveal the role of large snakes in connecting feeding guilds in a species-rich Amazonian snake community

In ecological communities, interactions between consumers and resources
lead to the emergence of ecological networks and a fundamental problem to
solve is to understand which factors shape network structure. Empirical
and theoretical studies on ecological networks suggest predator body size
is a key factor structuring patterns of interaction. Because larger
predators consume a wider resource range, including the prey consumed by
smaller predators, we hypothesized that variation in body size favors the
rise of nestedness. In contrast, if resource consumption requires specific
adaptations, predators are expected to consume distinct sets of resources,
thus favoring modularity. We investigate these predictions by
characterising the trophic network of a species-rich Amazonian snake
community (62 species). Our results revealed an intricate network pattern
resulting from larger species feeding on higher diversity of prey,
promoting nestedness, and specific lifestyles feeding on distinct
resources, promoting modularity. Species removal simulations indicated
that the nested structure is favored mainly by the presence of five
species of the family Boidae, which because of their body size and
generalist lifestyles connect modules in the network. Our study highlights
the particular ways traits affect the structure of interactions among
consumers and resources at the community level.