Wreaves are a fictional species of sentient beings in the Frank Herbert science fiction novels The Dosadi Experiment and Whipping Star.
Wreaves are approximately humanoid, but resemble insects in the way that the Gowachin resemble frogs: they have insectoid mandibles in place of mouths, faceted eyes, and a chitinous exo-skeleton.
Nonetheless, they are sentient, and take full part in the ConSentiency, or the collective of sentient species in the narrative universe in which the novels are set. They have a highly developed culture that involves clan relationships extended to the whole of the species by means of, essentially, wife-swapping: breeding females are traded between clans, creating extended family relationships between all wreaves. The 'distance' of the family relationship is immaterial. They have a strict code of honor, and to offend one wreave is to offend that wreave's family, which is effectively all wreaves, everywhere. Settling the dishonor means killing the offender, so to dishonor a wreave is to invite the wrath of the entire species upon oneself.
Wreaves are not known to gamble, so the expression "a wreave bet" means "a sure thing".