Science Puzzle
How Does a Flower Trick a Bee?
A flower offers a bee a reward of sweet nectar, and even paints lines on its petals like runway markings to guide the bee straight to it. This looks like pure generosity.
But the flower is getting something out of the deal too. What is the trick?
The Answer
The flower is using the bee as an unwitting courier. To reach the nectar at the centre, the bee must brush past the flower's pollen-tipped stalks, and it comes away with a dusting of pollen on its fuzzy back without noticing.
When that bee flies to the next flower for more nectar, some of the pollen rubs off onto that flower's female parts, and fertilisation happens. Plants cannot walk over to find a mate, so they bribe an animal to carry their pollen for them. The nectar is the payment; the pollen is the cargo the bee never agreed to carry.
The petal lines, called nectar guides, make the system efficient by steering the bee to land in exactly the spot where it will collect and deposit the most pollen. Some flowers even paint these guides in ultraviolet, a colour bees see and we cannot.
The principle: Coevolution and pollination. Flower and pollinator have shaped each other over time: the flower feeds the animal, the animal transports the pollen, and both benefit.