Susan Milius in Science News:
In a colony of tree wasps, workers on nursemaid duty crawl this way and that along the bottom of their nest, tending the youngsters in the comb. Most of the workers dutifully look after the queen’s offspring, stopping only to spit a runny meal into the mouth of a pale, lumpy larva snug in its cell. But one of these workers is up to no good. This selfish worker stays still for a minute or two in a suspiciously crouched position. She’s laying her own egg in an empty cell.
Such rogue egg laying is a crime against insect society. The wheels of justice, however, don’t require a special caste of investigators and prosecutors. Punishment among insects is meted out by ordinary workers—and sometimes the queen herself—says biologist Tom Wenseleers, who has watched dozens of hours of black-and-white videos from infrared security cameras that he’s trained on nests of tree wasps.
In the most dramatic episodes, the egg sneak finds herself surrounded by a posse of vigilante workers.