>> Not in this case as the pathogen isn’t going to react to the evolutionary defences of the bee by adjusting its infectiousness
> Of course it is
That is incorrect. Diseases might evolve to be more infectious. This is not a certainty.
There are many directions a disease can change and selecting to be more likely for a specific species is dependent on an N-vector calculus, with the most impactful cofactors being the length of time they (an attacking bee and a pathogen and the bee victim) coexist in the same environments and the utility of such an adaptation and the nature of the disease (ie incubation time, effects, etc) over time. It's likely the nature of a specific disease and the victim are going to vary more over time, making a favorable situation to prevent any attacking bee to simply not return.
