Plant resins – a neglected resource in the ecology of bees: How do resin plants and resin plant diversity influence bee colonies?

Tetrigona binghami (Meliponini) collecting resin from Hopea nervosa in lowland dipterocarp rainforest in Borneo (Malaysia)

The highly social honey bees (Apis mellifera) and tropical stingless bees (Meliponini) play a particularly important role as pollinators. Besides nectar and pollen, these groups of bees also collect resin, a sticky substance that is produced by plants and has antimicrobial and repellent properties. Bees use resin for nest construction and defense against natural enemies and pathogens. Because of its antibiotic properties, people used the mixture of various resins and wax that is produced by honeybees (propolis) in traditional folk medicine for centuries. Consequently, research has focused primarily on the chemical composition and the biological activity of propolis, whereas little is known about the importance of resins for the bees themselves. But several studies have shown that resin deters bee parasites and pathogenes, such as the causative agent of American foul-brood (Paenibacillus larvae), the varroa mite (Varroa destructor) and the small hive beetle (Aethina tumida).
Bees collect resins from tree wounds as well as from leaf buds, flowers and fruits of a multitude of plant species. Moreover, several stingless beee species transfer resin components to their body surface and thereby influence their chemical ecology. Consequently, plant resins represent an essential resource for these bees, and a lack of resin/ resin diversity may have a strong negative impact on colony health. We are interested in the origin of resin, the role of resin in the bees' social/external immunity and its use for self-medication as well as the influence of resin and resin diversity on the health and fitness of bee colonies.