It is widely known that bees collect pollen and nectar from flowers. It is hardly known that many bees, both solitary and social, also collect substantial amounts of plant resins from various plant species. Bees use resin to construct and defend their nests, to support their immune system and to increase the chemical and functional diversity of their chemical profiles. Yet, suprisingly little is known about resin foraging, the usage of resin in nests or the importance of landscape-related availability and diversity of resin-providing plants. For both temperate and tropical regions, we found bees to collect a broad spectrum of resin sources but also clear preferences for specific resins. Moreover, the spectrum of resin collected depends on the surrounding landscape and plant community. In fact, resin diversity is reduced in intensively used agricultural areas, with potential negative effects on its functional properties. Resin may thus play a strongly underestimated key function in the health of resin collecting bees.
