Investigations into the eco-immunological interactions between Drosophila melanogaster and its bacterical pathogens using experimental evolution

Abstract

Parasites and pathogens are omnipresent and affect the overall health of the infected hosts. It has been suggested that the identity of the pathogen can have a major effect on the evolutionary interactions and the associated costs. Further, hosts adapting to a particular pathogen are expected to trade-off their ability to withstand infection from a different pathogen. To assess the evolutionary consequences of host-pathogen interactions, I worked on two sets of evolved Drosophila melanogaster populations. In one set, I evolved flies against a Gram-positive bacterial pathogen, Enterococcus faecalis, while in the other set, they evolved against a Gram-negative pathogen, Pseudomonas entomophila. The immunocompetence of these evolved flies were explored to answer various eco- immunological questions, such as: (a) life-history traits and trade-off, (b) role of juvenile nutrition on adult immune function, (c) evolution of specificity, and (d) host fitness consequences of co-infection. Overall, I found that selected populations show (a) no trade- offs with life history traits, (b) survive better even under poor nutrition, (c) evol