A new oil bee pollination mutualism involving male-bee-pollinated orchids was discovered in tropical Asia

It is well known that animal-pollinated plants usually offer nectar or pollen to reward vectors for pollen transfer. While nectar is a kind of sugar water, pollen is protein-rich, a must-need nutrient for bee babies. The honey humans consume is made by female bee workers. Fifty years ago, German scientist Stefan Vogel first identified that droplets are non-water miscible 'nectar' but lipids in some flowering plants, discovering the so-called oil-flower, which offers oil as a reward for female bees.The oil bees collect fat droplets with special setae or abdominal hairs and then mix them with pollen as larval food or use the oil for nest lining. Worldwide, oil rewards are offered by about 150 genera in 11 families whose flowers are exploited by 370 species of oil-collecting bees.To date, our understanding of the ecology and evolution of the oil-bee and oil-flower interactions are mostly from studies in South America and South Africa, although in Asia, since the Early Eocene ...