Orchid flowers fool flat-footed flies by faking fungus-infected foliage

The lady’s slipper orchid (Cypripedium fargesii) does not look well. Its red and yellow flowers are nestled among two large leaves, both covered in unsightly black splotches. These look like the signs of a fungal infection, but they’re not. This orchid is deceptive, not diseased. It produces the black spots itself and in doing so, it lures in flat-footed flies that feed on fungus. The flies, duped by the orchid’s false spots, pick up pollen and spread it to another flower. By appearing infected, the orchid reproduces. There are many species of lady’s slipper orchids, but C.fargesii is an exceptionally rare variety. This critically endangered flower is found only in southwestern Chinese mountains. Zong-Xin Ren from the Chinese Academy of Sciences spent four consecutive summers on Yaoshan Mountain, almost 3,000 metres above sea level, studying a hundred or so of these rare flowers. It’s fairly easy to work out what ...