Figure 1: Environment-modifying secretions as a route to host generalism.
From: Cooperative secretions facilitate host range expansion in bacteria
We consider a scenario where pathogens can potentially transmit both within and among host species. Whereas specialists match their hosts closely (matching colours), generalists that infect multiple hosts are expected to have intermediate phenotypes (intermediate colour), meaning that they will lose to specialists during co-infections. While environmental modifiers may lose to specialists and generalists in the unmodified disease site, they can potentially invade by modifying this environment (transitions from red/blue to yellow) via the production of costly secretions (green triangles) that simplify the environment (loss of patterns). Specialists and classical generalists are not adapted to this modified environment, leading to their exclusion. While specialists and classical generalists are expected to show complex adaptations to their host(s) (complex shapes), environmental modifiers are expected to show simpler adaptations (simple shape), instead relying on secretions that modify and simplify their environment.
