Data from: Immune priming specificity within and across generations reveals the range of pathogens affecting evolution of immunity in an insect

1. Many organisms can improve their immune response as a function of their
immunological experience or that of their parents. This phenomenon, called
immune priming, has likely evolved from repetitive challenges by the same
pathogens during the host lifetime or across generation. 2. All pathogens
may not expose host to the same probability of re-infection and immune
priming is expected to evolve from pathogens exposing the host to the
greatest probability of re-infection. Under this hypothesis, the priming
response to these pathogens should be specifically more efficient and less
costly than to others. 3. We examined the specificity of immune priming
within and across generations in the mealworm beetle, Tenebrio molitor, by
comparing survival of individuals to infection with bacteria according to
their own immunological experience or that of their mother with these
bacteria. 4. We found that insects primed with Gram-positive bacteria
became highly protected against both Gram-positive and Gram-negative
bacterial infections, mainly due to an induced persistent antibacterial
response, which did not exist in insects primed with Gram-negative
bacteria. Insects primed with Gram-positive bacteria also exhibited
enhanced concentration of hemocytes, but their implication in acquired
resistance was not conclusive because of the persistent antibacterial
activity in the hemolymph. Offspring maternally primed with Gram-positive
and Gram-negative bacteria exhibited similarly improved immunity, whatever
the bacteria used for the infection. Such maternal protection was costly
in the larval development of offspring, but this cost was lower for
offspring maternally primed with Gram-positive bacteria. 5. While T.
molitor can develop some levels of primed response to Gram-negative
bacteria, the priming response to Gram-positive bacteria was more
efficient and less costly. We concluded that Gram-positive bacterial
pathogens were of great importance in the evolution of immune priming in
this insect species.