The ontogeny of immunity in the honey bee, Apis mellifera L.

This thesis examines the ontogenetic development of the honey bee immune
system in an ecological immunity context. I have optimised established
immunological techniques to examine how aspects of the constitutive and
induced innate immune response in the honey bee, Apis mellifera L., are
affected by life-history and parasite infection. I have used three optimised
immune assays to gain a measure of the timing and magnitude of specific
immune effector systems in the honey bee, and explored the consequences of
variation in immune efficacy throughout development and aging. The major
findings of this thesis are:
1. Neither workers or drones employ phenoloxidase for immune defence
in the pre-pupal stages
2. Sexual selection does not eliminate the need for an immune response
in adult drones
3. In both sexes, there is an ontogenetic up-regulation in immune
function with adult age
4. In the case of workers, this increase in immune response is not linked
to age polyethism, but rather a continuous increase in investment
beginning immediately after adult eclosion
5. Immune challenge results in a decrease in phenoloxidase activity,
and an increase in antimicrobial peptide production in adults
6. The antimicrobial peptide immune response shows signs of
senescence in immune challenged adult workers and drones
7. Colony investment in immune responses acts on a temporal scale
and responds positively to an increased threat of parasitism
8. Parasitism produces variation in colony defence strategies
9. Rainfall is an important factor in the successful establishment of an
infestation by the varroa mite, varroa destructor, in honey bees.