Pollen feeding in the eucalypt nectar fly, Drosophila flavohirta

Adults of the eucalypt nectar fly, Drosophila flavohirta Malloch (Diptera: Drosophilidae), feed on Eucalyptus pollen. Flies of both sexes gather pollen with the proboscis, forming a large mass of pollen on the anterior surface of the extended proboscis. Pollen gathering alternates with quiescent periods when the moistened pollen load is continually vibrated. No pollen was found in the adult gut, and it is suggested that hydration of the pollen causes release of nutrients which are then imbibed. This ‘external digestion’ is reminiscent of that employed by heliconiine butterflies.