A scientific note on an unusual hibernating stage in a late-flying European bee species

Abstract

Most temperate wild bees overwinter in the larval or imaginal stage inside their nests after the entire larval food provisions have been consumed. Here, we report on the finding that Colletes hederae (Colletidae), a late-flying European bee species active in September and October, passes the winter as half-grown larva inside the brood cell that still contains considerable amounts of stored food. We hypothesize that the special waterproof cell lining of Colletes reduces the risk of fungal infection, liquefaction, or desiccation of the stored food and thus liberated the bees from the need to consume the entire provisions before winter, allowing for the exploitation of late-flowering plant taxa.