Can Plants Hear When Pollinators Approach?

Research has shown that bees are able to detect differences in sugar concentration among flowers. So while buzzing around a garden full of flowers, they can zero in on the sweetest nectar, even when the sugar content differs by less than three percent. A 2019 study conducted by Tel Aviv University researchers scrutinized another aspect of that symbiotic relationship. The study seems to indicate that some flowers can “hear” the approach of a bee -- in the sense that it detects sound waves -- and can increase sugar content by as much as 20 percent within three minutes of sensing the bee’s hum.

Here's the latest buzz:

• Lilach Hadany and her research team studied the beach evening primrose, exposing the flowers to a variety of sound levels, ranging from silence to computer-generated sounds at various frequencies.
• They found that the flowers increased nectar sugar concentrations when exposed to the sound of honeybees (0.2 to 0.5 kilohertz) at a distance of four inches (10 cm), as well as other low-frequency sounds (0.05 to 1 kilohertz).
• The flowers had no response when exposed to silence, or to high and intermediate frequency sounds. The bowl-shaped primrose blooms also did not respond to vibrations when their petals were removed.

Frequently Asked Questions

Can plants actually detect the presence of pollinators?

Yes, plants can detect the presence of pollinators. Research has shown that some plants can sense the vibrations caused by pollinator activity, such as the buzzing of bees. For instance, a study published in the journal "Ecology Letters" found that the evening primrose plant increases its nectar production within minutes of sensing the vibrations from pollinator wings, enhancing its chances of being pollinated.

How do plants 'hear' pollinators if they don't have ears?

Plants 'hear' through a form of mechanoreception, where they perceive mechanical vibrations in their environment. They don't have ears like animals, but they can sense the tiny vibrations caused by pollinator movements or the sound of their wings beating. This triggers certain responses in the plant, such as altering nectar production, as a way to attract the pollinators.

What kind of responses do plants have to the sound of pollinators?

Plants can respond to the sound of pollinators by changing their physiology or behavior to become more attractive to them. For example, some plants increase their nectar production, as demonstrated in the study of the evening primrose. This response is thought to be an evolutionary adaptation to improve the chances of successful pollination and reproduction.

Does the ability to detect pollinators give plants an evolutionary advantage?

Yes, the ability to detect pollinators can give plants an evolutionary advantage. By responding to the presence of pollinators, plants can optimize their resources, like nectar, to attract these beneficial insects precisely when they are nearby. This increases the likelihood of pollination and can lead to greater reproductive success, which is a key driver of evolution.

Are there specific types of plants that are more sensitive to pollinator sounds?

While research is ongoing, it appears that certain plants, particularly those that rely heavily on pollinators for reproduction, may have developed greater sensitivity to pollinator sounds. The evening primrose is one example, but other flowering plants that depend on insect pollination may also have similar capabilities. The extent of this sensitivity can vary widely among plant species.

Could this discovery impact agricultural practices or pollinator conservation efforts?

This discovery could have significant implications for agriculture and conservation. Understanding plant-pollinator interactions at this level could lead to the development of crops that are more attractive to pollinators, potentially increasing yields. Additionally, it highlights the importance of pollinator conservation, as their presence can directly influence plant health and productivity, which is vital for ecosystems and human food supplies.