To work or not to work

摘要

Coercion, not kinship, often determines who acts altruistically in an insect colony. But underlying affinities for kin emerge when coercion is removed: kin selection is what turns suppressed individuals into altruists. When Shakespeare's Prince Hamletremarked that his uncle Claudius was "A little more than kin..." he was referring to the added relationship of stepfather that came after Claudius killed Hamlet's father and married his mother. "A little more than kin" could also describe a feature of many social insects. Owing to their odd genetic system, called haplodiploidy, full sisters in ants, bees and wasps are related by 3/4, more than a little above the standard value of 1/2. Historically, this extra kinship figured prominently in the acceptance of W. D. Hamilton's theory of kin selection1, which holds that workers evolved to altruistically forgo reproduction because they can pass on more of their genes by raising siblings. But a series of papers2"5, including one on page 50 of this issue3, shows that the other half of Hamlets description - "...and less than kind" - may be more apt. Workers are less than kind both because they must be coerced into their 'altruistic' roles and because workers are often also the ones doing the coercing.