Orchids display such a crazy diversity of structure, color, pattern, and fragrance. This is Part 3 in my series of blog posts investigating orchid pollination strategies. What makes orchids so weird?
It just makes scents
Many insects produce volatile pheromone cocktails to attract mates, but there is a group of bees that actually collects compounds from its environment. Euglossine bees are beautifully shiny neotropical bees. The males spend their time searching for fragrant chemicals to collect and store in their enlarged hind limbs. Presumably the scents are then used by the male to attract mates, but female attraction to fragrant male euglossine bees has yet to be demonstrated.
The male bees are so focused on collecting scented compounds that they can easily be attracted by setting out any kind of smelly oil in the jungle. An orchid that could exploit such a drive would be able to attract an abundance of pollinators. That is precisely what Stanhopea and Catasetum orchids have done. The flowers provide a surface covered in smelly volatiles inside a strangely contorted set of petals. The petal arrangement is such that any euglossine bee that flew in to collect his perfumes would rub up against the pollen and take it with him when he leaves.
Other interesting facts about euglossine bees:
There is a species that is attracted to and even collects large amounts of DDT (dichlorodiphenyltrichloroethane) insecticide with no apparent problems.
Also, if you are a fan of The Big Bang Theory, you may have heard that a new species of bee was named Euglossa bazinga. True fact.
Stanhopea tigrina flowers from the bottom of the plant so that the flowers hang upside down. The lower lip of the flower is covered in fragrant compounds that attract the male euglossine bees.