Question

Many insect species carry the endosymbiotic bacteria Wolbachia, which are maternally inherited. Wolbachia persist over time in these insect hosts by increasing the fitness of the infected host. This increased host fitness can lead to the fixation of Wolbachia in the host population, wherein all individuals carry it. Which one of the following statements describes a process that would NOT allow Wolbachia to become fixed in the host population?

• A. Wolbachia induce cytoplasmic incompatibility and so, mating between infected and uninfected host individuals produces no viable offspring
• B. Wolbachia increase the fecundity of the host by increasing its longevity
• C. Wolbachia increase the immune response of the host to other infections
• D. Wolbachia induce cytoplasmic compatibility and so, only mating between infected and uninfected host individuals produces viable offspring

Hint:

Cytoplasmic incompatibility (CI) is essential for the spread of Wolbachia, as it prevents the successful reproduction of uninfected females with infected males. Cytoplasmic compatibility would counteract this effect and reduce Wolbachia’s ability to spread in the population.

Answer 1

The Correct Option is D

Step 1: Understand the effect of Wolbachia on the host population. 
Wolbachia are maternally inherited bacteria that can affect host fitness in different ways. Some effects include cytoplasmic incompatibility (CI), which causes incompatible crosses between infected and uninfected individuals, increasing the spread of Wolbachia. 
Step 2: Analyzing the options.
Option (A) describes Wolbachia inducing cytoplasmic incompatibility, which is a key mechanism that allows Wolbachia to spread by preventing the successful reproduction of uninfected females and infected males.
Option (B) describes an increase in the fecundity (reproductive success) of the host, which also helps Wolbachia spread.
Option (C) describes an increase in the immune response, which could lead to a fitness advantage for infected hosts, helping Wolbachia persist in the population.
Option (D) describes cytoplasmic compatibility, where mating between infected and uninfected individuals produces viable offspring. This would reduce the spread of Wolbachia because the incompatibility is key to its spread. 
Thus, the correct answer is (D) because cytoplasmic compatibility would allow uninfected individuals to reproduce successfully with infected individuals, reducing Wolbachia's spread.