Adults occurs frequently from May to August. They are phytophagous. They feed on leaves, flowers and pollen of deciduous trees, mainly of Quercus robur, Salix, Populus, Betula, Fraxinus excelsior, Fagus sylvatica, Dorycnium, Prunus, Ulmus and Corylus avellana. They feed also on pollen of Rosa canina, Polygonum bistorta and Leucanthemum vulgare.
Clytra laeviuscula has a special relationship with ants. The females wrap each egg with their hind legs in a ball of about 2 mm of excrements/feces
and leaves it in the vicinity of an anthill. The eggs are taken to the nest by ants, where the larvae made a kind of tube that serves to protect them from ants. They feed on the waste and other detritus left by the ants, on their eggs and on their larvae. The adults usually emerge after about two weeks. The larval cycle lasts about two years.