hard · GRE Verbal

Passage: In many eusocial insects, workers forgo reproduction to rear a queen's offspring, a self-sacrifice long explained by kin selection: because sisters share, on average, three-quarters of their genes, aiding the queen propagates a worker's own genome efficiently. Recent modeling questions whether this coefficient does the explanatory work once assumed. In colonies with multiple mated queens, or where a single queen mates with several males, average relatedness among workers falls well below the three-quarters threshold, sometimes approaching that of ordinary siblings. Yet sterility persists. This suggests that ecological constraints—the prohibitive cost of a lone female founding a new colony—may sustain worker altruism independently of, and perhaps prior to, the genetic bookkeeping that kin selection tallies. It can be inferred that the author regards the three-quarters relatedness coefficient as:

1. The single sufficient factor that could account for the evolution of worker sterility
2. Insufficient by itself to explain worker sterility in all colony structures
3. A value that recent modeling has shown to be mathematically miscalculated
4. Wholly irrelevant to the observed behavior of any known eusocial insect species
5. More important in multiply-mated colonies than it is in singly-mated ones

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