  Human history has been shaped by armed conflicts. Rather than large-scale
interstate wars, low-intensity attacks have been more prevalent in the
post-World War era. These attacks are often carried out by non-state armed
groups (NAGs), which are supported by host states (HSs). We analyze the global
bipartite network of NAG-HS support and its evolution over the period of
1945-2010. We find striking parallels to ecological networks such as
mutualistic and parasitic forms of support, and a nested and modular network
architecture. The nestedness emerges from preferential behaviors: highly
connected players are more likely to both gain and lose connections.
Long-persisting major modules are identified, reflecting both regional and
trans-regional interests, which show significant turnover in their membership,
contrary to the transitory ones. Revealing this architecture further enables
the identification of actor's roles and provide insights for effective
intervention strategies.
