• Question: why do some flowers give of different scents and do these plants/flowers scents attract the different types of bees, honeybees and hover flies.

    Asked by anon-218615 to Richard, johnpaterson, Emma, Anna on 21 Jun 2019.
    • Photo: Emma Markham

      Emma Markham answered on 21 Jun 2019:

      Wow, I did not know the answer but I have looked it up and learned something new. So yes, plants have different scents to help attract different pollinators which they are adapted for. Plant species pollinated by bees and flies have sweet scents, whereas those pollinated by beetles have strong musty, spicy, or fruity odors.There is a great article about it here: https://www.scientificamerican.com/article/why-do-flowers-have-scent/

      Also, did you know that flowers can detect the vibration from bee’s wings and when they know bees are close by they will increase the sugar in their nectar! So the plant is able to tell when there is a bee and because it wants to be pollinated by the bee rather than another pollinator it will reward it with more sugar!

    • Photo: John Paterson

      John Paterson answered on 21 Jun 2019:

      Yes, flowers give off different scents to attract different pollinators. Plants that smell sweet are often trying to attract bees, hoverflies or (in some parts of the world) bats. Flowers will sometimes smell horrible and that’s often because they want to attract flies that would normally be attracted to dung or rotting meat – one of these is called the corpse flower and it’s one of the biggest flowers in the world: https://en.wikipedia.org/wiki/Amorphophallus_titanum

      One of the other people in my lab is researching this at the moment. He is using a little vacuum cleaner to suck all the air from a plant into a bag to trap its smell. He’s then going to send it away to get it analysed so that he knows what different chemicals are making it smell like that.

      Flowers also look different depending on what they want to attract. Flowers that want to attract bees and butterflies are often blue, purple, yellow or violet and often have a long flower, so only bees and butterflies with their long tongues can get at the nectar they make. Flowers that want to attract flies are often white or yellow and are flat, so the flies (which don’t have long tongues) can get at the nectar. In some parts of the world, like South America or South Africa, birds are common pollinators, like hummingbirds. Flowers that attract them are often bright colours like red, because birds have good eyesight, but they don’t have a strong scent because birds have a very bad sense of smell.

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