The antennae of iridescent bees detect the scent of individual orchid species using especially sensitive chemoreceptors.

References

In the forests of Central America, "Each of the twenty or so species of bucket orchid has its own brand of scent. Although human nostrils cannot distinguish between them, the iridescent bees that live in these forests certainly can. Each species of orchid attracts its own species of bee." (Attenborough 1995:108)

Book
The Private Life of PlantsFebruary 27, 2017
David Attenborough