A univoltine species: August to November. In Britiain, the species flies from mid-September to early November.
Parasites & predators: The Meloid beetle Stenoria analis is a parasite of the bee in the Channel Islands and France but has not yet been found in Britain. There is evidence that patrolling males of C. hederae hover in front of, and are strongly drawn to, larval aggregations of S. analis in a manner reminiscent of approaching flights to emerging, conspecific females. Not only are the male bees strongly attracted by clusters of newly hatched triungulins, but they also attempted copulation (i.e., pseudocopulation) with the latter, which regularly resulted in small groups of triungulins being transferred onto the thorax of the male bees. Decent-sized groups of triungulins were exclusively found on the thorax of male bees, which suggests that triungulins of S. analis lure only males of the targeted host species, presumably by mimicking the female pheromonal cues of C. hederae. This is the first record of this kind of interaction for the whole West-Palaearctic, and only the second account on sexual deception between blister beetles and wild bees described to date.The triungulin larva of the beetle eventually slip off the bee and consume the food store of nectar and pollen that the female bee has prepared for its larva. (N.J. Vereecken & G Mahé, 2007).
In south-west Slovenia, Gogala (pers. comm) has observed the cleptoparasitic bee Epeolus cruciger associating with C. hederae and Epeolus cruciger was also found to be a common parasite of C. hederae in southern Switzerland (Ticino) as well as in the Monte Gargano area in Puglia (Italy) (Müller pers. comm.). Westrich (pers. comm.) also suggests that Epeolus fallax is associated with this species.