Damaraland mole-rats are relatives of naked mole-rats. In their clans, too nonbreeding individuals of both sexes cooperatively assist one breeding par. Even so, breeding individuals in wild Damaraland mole-rat colonies usually are unrelated, and few suboordianes move up in the hierarchy to breeding status. Researches suspect that ecological factors, not genetic ones, were the more important selective forces in Damaraland mole-rat altruism. Explain why.

To explain why ecological factors, rather than genetic ones, were likely the more important selective forces in Damaraland mole-rat altruism, we need to understand the concept of inclusive fitness and the way natural selection operates.

Inclusive fitness refers to an organism's overall reproductive success, not only through its own offspring, but also through the reproductive success of genetically related individuals. Natural selection favors traits and behaviors that increase an individual's inclusive fitness, even if it means sacrificing personal reproduction for the benefit of others in the group.

In the case of Damaraland mole-rats, they display cooperative behavior by assisting one breeding pair within their clan, even though they themselves are nonbreeding individuals. This cooperative behavior is considered altruistic because these individuals are helping care for and protect the breeding pair's offspring, rather than reproducing themselves.

The fact that breeding individuals in wild Damaraland mole-rat colonies are usually unrelated suggests that genetic relatedness is not a significant factor in their altruistic behavior. If genetic relatedness was the primary driving force, we would expect to see a higher proportion of related individuals within a colony. Instead, the structure of Damaraland mole-rat colonies indicates that ecological factors play a more important role in their altruism.

One possible ecological factor influencing Damaraland mole-rat altruism is resource availability. Damaraland mole-rats live in arid regions of Africa, where resources can be scarce. By assisting the breeding pair and their offspring, nonbreeding individuals contribute to the overall survival of the group as a whole. This cooperative behavior may increase the chances of survival and reproductive success for all members of the colony, including themselves in the long run.

Another ecological factor that could influence Damaraland mole-rat altruism is predation pressure. By cooperating and working together, the colony as a whole may be more effective at defending against predators. This increased defense ability benefits both the breeding pair and the nonbreeding individuals, enhancing their overall chances of survival and reproductive success.

In summary, the observed lack of genetic relatedness among breeding individuals in Damaraland mole-rat colonies suggests that ecological factors, such as resource availability and predation pressure, are likely the more important selective forces driving their altruistic behavior. These factors create a scenario where the inclusive fitness gained through cooperative behavior outweighs the benefits of individual reproduction, leading to the evolution of altruism in Damaraland mole-rats.