Many plants produce toxic chemicals to protect themselves against plant-eating animals, and many flowering plants have evolved flower structures that prevent pollinators such as bees from taking too much pollen. Now ecologists have produced experimental evidence that flowering plants might also use chemical defences to protect their pollen from some bees.
The results are published next week in the British Ecological Society’s journal Functional Ecology.
In an elegant experiment, Claudio Sedivy and colleagues from ETH Zurich in Switzerland collected pollen from four plant species — buttercup, viper’s bugloss, wild mustard and tansy — using an ingenious method. Instead of themselves collecting pollen from plants, the researchers let bees do the leg work, harvesting pollen from the nests of specialist bees which only feed on one type of plant.