Buzzzzing pollinators and flower “ears"

With the onset of a new season there are all sorts of sounds around us, from insects fluttering, to frogs croaking the night away. Very seldom do we consider the effect of sound on sessile organisms like plants. Plants have many attributes that attracts pollinators, but did you know that sound benefits certain pollinator species and is even necessary for the cooperation with the flower?

Ever wonder why a honeybee buzzes around as it flies, other than letting us know that they are there. This is not done without reason, the sounds produced by insects, like bees, alerts plants of their presence. Petals from the new blooming flowers act as auditory organs or “ears” of the flowers and picks up on specific frequencies of wing beats from pollinators. Within the first three minutes of picking up this vibration from the pollinator, the flower reacts by increasing the sugar content in the nectar it produces. Nectar is the main source of carbohydrates for pollinators and assists certain species, like honeybees in the production of honey, which in return feeds the hive when no nectar is available from flowers.

This sweeter food source not only attracts the pollinator, but it also ensures that it will revisit this species of flower. This ensures the reproductive success of the plant. Within the first few days of spring in the Lowveld we witness several species of flowering plants bloom and within a few days the beautiful flowers die off, leaving the plant structure without colour. This shows the importance of the flower’s nectar being as irresistible as possible. On top of having beautiful flowers for the next season this smart adaptation from flowers also saves them energy, knowing when the production of sweeter nectar is needed and when not.

Another method that some bee species use for pollination is called sonication or “buzz pollination”. This takes place on the anthers of the flowers. Anthers are the top part of the stamen or male organ of the flower, which produces the pollen. A bee will attach itself to the anther and vibrate its abdomen using flight muscles. The vibration shakes the pollen loose from pores on the anther and gives the bee access to it. Many different wildflowers need buzz pollination to ensure they reproduce and even some of our favourite cultivated fruits like blueberries and tomatoes rely on the busy bees.