Meerkats are said to exhibit altruistic behavior because certain members act as sentries. These sentries stand on rocks or other high places and serve as lookouts while others feed. However, recent observations have shown that these sentries are the first ones to reach safety when a predator is spotted, and that sentries only serve after they have eaten. Their behavior is still beneficial to the group since without the sentries there would be no warning of approaching predators, but can it still be termed altruistic? How would you test the hypothesis that sentries are engaged in altruistic behavior?
In the winter moth life cycle, parasites were found to be a less important cause of mortality than cold winter weather and predators. Give an evolutionary explanation for the inefficiency of parasites in controlling population size.