Science and Engineering Research Board, Department of Science and Technology, Government of India will be supporting my visit to ESEB 2017 at Groningen, Netherlands and Ecological Immunology Workshop 2017, Blossin, Germany. I will speak about our recent experimental evolution results on ‘memory in insect immunity’
Under strong pathogen pressure, insects often evolve resistance to infection. Many insects are also protected via immune memory (immune priming), whereby sub-lethal exposure to a pathogen enhances survival after secondary infection. To understand the evolution and consequences of these immune responses, we imposed strong pathogen selection on flour beetles (Tribolium castaneum), infecting them with Bacillus thuringiensis (Bt) for 11 generations. Populations injected first with heat-killed and then live Bt each generation evolved high basal resistance against multiple Bt strains. In contrast, all populations injected only with a high dose of live Bt evolved less effective but strain-specific priming response. Control populations injected with heat-killed Bt did not evolve priming; and in the ancestor, priming was effective only against a low Bt dose. Thus, pathogens can select for rapid modulation of insect priming ability, leading to divergent immune strategies (generalised resistance vs. specific immune priming) with distinct mechanisms and adaptive benefits.