Drosophila melanogaster hosts coevolving with Pseudomonas entomophila pathogen show sex-specific patterns of local adaptation

Abstract

Background In spatially structured populations, local adaptation improves organisms’ fitness in their native environment. Hosts and pathogens can rapidly adapt to their local antagonist. Since males and females can differ in their immunocompetence, the patterns of local adaptation can be different between the sexes. However, there is little information about sex differences in local adaptation in host–pathogen systems. Results In the current study, we experimentally coevolved four different replicate populations of Drosophila melanogaster (host) and Pseudomonas entomophila (pathogen) along with appropriate controls. We used the four host–pathogen coevolution populations to investigate the occurrence of local adaptation separately in males and females of the coevolving hosts. We also assessed local adaptation in pathogens. We set up a reciprocal infection experiment where we infected each of the four coevolving hosts with their local pathogen or non-local pathogens from the other three replicate populations. We found that overall, male and female hosts had better survivorship when infected with local pathogens, indicating that they were locally adapted. Interestingly, males were more susceptible to non-local pathogens compared to females. In addition, we found no fecundity cost in females infected with either local or non-local pathogens. We found no evidence of local adaptation among the pathogens. Conclusion Our study showed sex-specific adaptation in the coevolving hosts where female hosts had a broader response against allopatric coevolving pathogens with no cost in fecundity. Thus, our results might suggest a novel mechanism that can maintain variation in susceptibility in spatially structured populations.

Evolution of resistance and disease tolerance mechanisms to oral bacterial infection inD. melanogaster

“…It is well described that the route of infection is of paramount importance to the outcome of hostparasite interactions In D. melanogaster, the mode of entry of a bacterial pathogen into the host's body elicits different physiological responses 19,[57][58][59][60][61] , which can start by the avoidance of the pathogenic substrate, in the case of infection through oral route 26,62,63 , both by inhibiting feeding or choosing oviposition sites according to bacterial composition 26,53,[62][63][64] . P. entomophila is a natural pathogen of Drosophila that causes high mortality when ingested across diverse genetic backgrounds and conditions 23,43,44,65,66 . Thus, it is plausible to consider that fasting could constitute a general response against oral infection.…”

A diverse gut virome fromDrosophila melanogaster

“…However, information about phages as an important component of microbiome infecting most species, is still lacking. This is also true for the well-studied model organism Drosophila , despite being a powerful model for gut microbiome research [9, 10] and the study of evolution and ecology of host-microbe interactions [11, 12].…”