Wasp Pollination. Chrysis sp. , a cuckoo wasp with striking metallic colours of ruby-red, green and blue, feeds on the nectar of the yarrow flower Achillea millefolium. This is a daisy- like flower. The cuckoo wasp, attracted to the nectar as a food source, unwittingly collects pollen on its body; in this way pollen is spread from flower to flower and the yarrow is pollinated. The genus Chrysis is a large group of wasps, all of which have inscuckooins behaviour of laying their eggs in the nests of other wasps and bees. In this way their offspring, if undetected, are raised by other Hymenopteran species.