Three of Cups

The Three of Cups is the party: three maidens dancing in a garden with their cups raised. Franky saw "three individuals intermingling in ménage à trois of good will," and added, "This is the perfect occasion for parasitism."

The paper wasp Polistes dominula keeps a strict household. Workers build, feed and defend; future queens rest and fatten for winter. Xenos, which is Greek for stranger and for guest, comes in through the nursery. Its tiny larvae ride a foraging wasp home and slip into the grubs in their cells without leaving a wound. The wasp grows up with a lodger feeding on her hemolymph, and she never develops ovaries. About a week after leaving her cell, before the parasite even shows, she walks out on the nest.

She goes to a party. Infected wasps from many colonies cluster on prominent leaves. In one study up to 98 percent of the guests were parasitized. The guests do almost nothing, because it's the parasite's dance floor. A male Xenos emerges as a winged insect that lives four to six hours, just long enough to find a female who never leaves her wasp: no eyes, legs or wings, only a front end poking out between the wasp's abdominal plates, calling with a scent. Afterward the wasps carrying females winter with the real future queens, outlive the workers they were meant to be, and in spring carry the next larvae to new nests and flowers. The counterfeit queen outlasts the original.

These gatherings were first noticed by W. D. Hamilton, who explained with kin-selection mathematics why worker wasps give their lives for their sisters. The man who wrote the rules for staying found the wasps who left. Some gnostic myths tell of a foreign spark sown in every newborn, which spends its life looking for its own kind. Xenos is that story told from the wasp's side. So enjoy the people who make three better company than two, and then ask who sent the invitations, and when. Some of your most loyal crowds were chosen for you before you could choose.

Invitations to this party are delivered in the nursery.