Most queen bees aren't born to rule. The colony decides which female larvae to rear as future monarchs, places them in larger cells, and gives them extra food. But in the stingless Melipona bees, queens are born physically different from workers: They have larger abdomens, smaller heads, and none of the pollen baskets found on workers' legs. One in five Melipona females is born a queen, which could create enormous internal strife, since most will never get to reign; zealous workers often kill virgin queens to eliminate the threat to the incumbent. However, the surplus queens have a solution: conquer other hives. To see how often these invasions occur, researchers tracked queen replacement in Melipona hives in Brazilian laboratories over 3 years. After a queen died (or was removed), the scientists genotyped her successor to determine if she was a daughter or an alien. One out of every four inheritors came from another hive, they report  online today in Biology Letters. Though with droves of killer worker bees at home, conquest is just as much about survival as it is about power.
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