[Rudder]

Moreover, the bacterium induces the insects to produce a larger number of daughters, advantageous for a bacterium that is passed to the next generation only by the females.

Actually, I'm not sure whether either evolved (as depicted in this scenario), but the bacterium has exploited or manipulated the birth ratios of the insect. Could be mutual adaptation.

[Boogieman]

“Actually, I’m not sure whether either evolved (as depicted in this scenario), but the bacterium has exploited or manipulated the birth ratios of the insect. Could be mutual adaptation.”

It could be that the insects who carry the trait to resist the bacteria also happen to carry the other traits observed. Or, the bacteria could have found some way to affect the insect’s biochemistry, but it’s only observable in insects that could survive the infection.

It does remind me of Lynn Margulis’ theories about bacteria being much more of a factor in evolution than random mutations.