Re tolerance vs resistance:
When faced with parasites, hosts can utilize two strategies to maximize fitness. They can reduce parasite burden by avoiding or directly attacking parasites, or they can minimize the harm caused by a given parasite load. Since the late 1800s, these strategies have been referred to as resistance and tolerance, respectively, by plant biologists. Only recently have animal biologists empirically deconstructed variation in pathogen control (resistance) and damage control (tolerance). Furthermore, these studies have emphasized variation within a species among genetic lines.
Rohr, J. R., Raffel, T. R., & Hall, C. A. (2010). Developmental variation in resistance and tolerance in a multi‐host–parasite system. Functional Ecology, 24(5), 1110-1121.
As applied to bees:
The A. m. scutellata population studied here shows
no conclusive evidence of tolerance towards the
effects of infestation by V. destructor.
In contrast, clear evidence for resistance was
found in the low fertility, fecundity and reproductive
success of Varroa mite foundresses.
This low reproduction
explains the slow rate at which mite
populations grow in savannah honeybee colonies
and may constitute the major adaptation allowing
for colony survival.
The absence of acaricide use in
savannah honeybee colonies may have facilitated
the development of this resistance by allowing
natural selection to take place.
Nevertheless, a more detailed understanding is
needed in order to identify all the possible behaviours
of the savannah honeybee from South
Africa (e.g. hygienic and grooming behaviour,
swarming frequency) that may contribute to
keeping mite numbers low and consequently reducing
and/or preventing mite population growth
above the damage threshold for the colony.
Strauss, U., Dietemann, V., Human, H., Crewe, R. M., & Pirk, C. W. (2016). Resistance rather than tolerance explains survival of savannah honeybees (Apis mellifera scutellata) to infestation by the parasitic mite Varroa destructor. Parasitology, 143(03), 374-387.
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