> fitness values for success in exploiting an environmental niche.

In the case of the honey bee, adaptability is one of its chief qualities. This confers the fitness benefit of being able to thrive in a vast range of environments. This is the exact opposite of niche exploitation, where a species thrives only in a particular niche. Many human selected species have this trait, that they can only thrive in very specific circumstances, like hothouse flowers. 

These are two different sorts of fitness values. One: adaptability which confers fitness in changing conditions, and two: fitting into a niche, where one is protected from changing conditions. Adaptability confers true fitness in terms of resilience and long term survival, while niche-fitness buys time until conditions change, and the species finds itself lacking adaptability and ill prepared.

A high degree of adaptability is a trait which has evolved and enables a species to persist despite climate change, varying conditions and a kaleidoscope of predators. This is why the African bee is a successful invader. The ability to exploit a specific niche has survival value -- many species persist in niches for millions of years -- but if that niche were to be radically altered, they could easily go extinct. 

An example would be blind salamanders. They do fine in caves where there are no predators, but outside they wouldn't last. A similar example is lab mice. These require high maintenance from humans, and could not survive in the wild for two days. 

The chief question in my mind is this: are mite resistant lines that have been identified in Europe surviving because they have adapted in a particular niche, or do they have traits that would permit them to survive in a range of environments like the African bee? 

¶

> In 2007, the bee research group of Wageningen University started a selection program on 2 groups of colonies kept isolated in Tiengemeten island and Amsterdam Water dunes. The colonies were kept without Varroa treatment and selected on survival, growth and reproduction criteria. Upon the 2 groups, selected colonies rapidly acquired resistance to Varroa mites and are now able to survive without any treatment against the mite.  

Panziera, D. 2015. Naturally selected resistance against Varroa mites may use different mechanisms 

> The capacity of organisms to respond in their own lifetimes to new challenges in their environments probably appeared early in biological evolution. At present few studies have shown how such adaptability could influence the inherited characteristics of an organism’s descendants. By their adaptability, organisms are able to modify their behaviour in response to novel conditions. The coping might be only partial but could be sufficient to ensure survival.

Bateson, P. 2017 Adaptability and evolution.

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