Wolbachia analysis
Wolbachia are endosymbiotic alpha-proteobacteria that are present
in about 70% of butterfly species and induce diverse reproductive
alterations, including genetic barriers when two different strains
infect the same population or when two populations – one infected and
one uninfected – meet. As potential evidence for a reproductive barrier
promoting the separation of Xerces Blue and Silvery Blue, we searched
for Wolbachia DNA reads in our specimens, taking advantage of the
high coverage and the shotgun approach, but failed to detect a solid
presence (between 0 and 0.02% of DNA reads not attributable to our
butterflies, depending on the specimen) of this bacterium.