Hedychrum rutilans is a cleptoparasite and parasitoid of larvae of beewolves (Philanthus triangulum and Philanthus coronatus). The female cuckoo wasp lays its eggs on the paralyzed honeybee workers serving as provisions for the beewolf larvae, placed by the female beewolf in its brood cells. The cuckoo wasp larvae feed on the honeybees and on the larvae of the beewolf. Adults grow up to 4–10 mm (0.16–0.39 in) long and can be encountered from late
June to September, often feeding on flowers of Mentha species, Achillea millefolium and Euphorbia paralias, but also on honeydew or various exudates. They prefer sandy and warm habitats.
