Coexistence of nestedness and modularity in host-pathogen infection networks

Area of Science:

• Ecology
• Evolutionary Biology
• Network Theory

Background:

• Host-pathogen coevolution creates complex interaction networks.
• Environmental heterogeneity influences network structure, impacting disease dynamics.
• Understanding spatial variation in network properties like nestedness and modularity is crucial but often lacking.

Purpose of the Study:

• To develop a neutral model for host-pathogen network evolution across multiple habitats.
• To investigate the coexistence of local modularity and global nestedness.
• To link environmental heterogeneity and intraspecific competition to network structure.

Main Methods:

• Proposed a neutral model for host-pathogen network evolution in multi-habitat settings.
• Analyzed the continuum between nested-modular and nested networks.
• Validated theoretical predictions using a longitudinal plant-virus interaction study.

Main Results:

• Local modularity can coexist with global nestedness in host-pathogen networks.
• Ecosystems exhibit a structural continuum influenced by intraspecific competition.
• Nestedness is driven by neutral community assembly, while modularity depends on local adaptation and competition.

Conclusions:

• Network structure (nestedness and modularity) can vary spatially and temporally but remains stable over evolutionary time.
• Intraspecific competition is a key driver of the observed network structures.
• The findings provide insights into disease dynamics and emergence in heterogeneous environments.