Two subspecies of salamanders in Southeast Asia, salamander S1 and Salamander S2, are thought to have diverged genetically and morphologically through sympatric speciation. At the southern tip of their respective native ranges, they can co-occur in secondary contact. They can mate successfully and produce viable, fertile offspring; the offspring can therefore also reproduce. However, the hybrid offspring have a coloration that is disproportionately attractive and easily detectable by predators, leading to decreased survival.
The relatively low fitness of the S1 x S2 hybrid salamander would be an example of:
a. postzygotic behavioral isolation
b. gametic incompatibility
c. mechanical isolation
d. reinforcement
e. prezygotic isolation
Assuming that mating occurs freely in secondary contact, what is the fitness of the parent salamanders S1 and S2 in the scenario?
a. low. Fitness involves reproductive success and survival; if survival is low in the offspring, the parents cannot pass their genes on to future generations.
b. zero.
c. high. Fitness involves reproductive success and survival, the parents are reproductively successful and able to survive.
d. high. Fitness of the parents is not related to the fitness of the progeny.
e. none of the above