What is the immediate fitness consequence for a host in an obligate relationship if separation from the symbiont occurs?

Answer

The fitness drops to zero immediately upon separation.

In an obligate relationship, fitness drops immediately to zero upon separation because the host relies entirely on the symbiont for a critical function, acting as a powerful, non-negotiable evolutionary driver enforcing the bond.

What is the immediate fitness consequence for a host in an obligate relationship if separation from the symbiont occurs?
biologyevolutioninteractioncoevolutionsymbiosis