09/23/2021 at 9:02 AM CEST
Researchers have discovered that the electrical charge of bees and bumblebees stimulates nearby flowers to enhance their aroma emission. This is the first time that a plant uses the presence of pollinators, specifically its electricity, as a signal to emit more of its attractive perfume, which increases its chances of being visited.
The small electrical charge carried by bees is believed to help pollen adhere to them during flight, but the team of researchers from the University of Bristol, Rothamsted Research and the University of Cardiff found that it can also serve to advertise their presence to the flowers they visit.
According to lead author Dr. Clara Montgomery, who was funded by the BBSRC, this curious quality possibly evolved in plants with the purpose of maximizing the effectiveness of the attractive chemicals they release.
“Flowers have a limited supply of these scents, so it makes sense that they only release them when their pollinators are around. Basically, it’s only worth advertising when you know you have an audience. Other signals they might use, such as daylight or temperature, can be unreliable as it can also be windy or rainy, reducing pollinator presence & rdquor ;, he noted.
“These scents are also used by insects that just want to eat or lay eggs on the plant, so increasing their chances of attracting only pollinators is vital,” Montgomery added.
The electrical charge on a bumblebee, somewhere in the 120 picoCoulomb (pC) region, is incredibly small, but the team found that a 600 pC charge, or roughly the same as five visits from bees, was enough to induce a species of violet petunia, Petunia integrifolia, to release noticeably more aroma than usual.
Using specially constructed feeding mechanisms for the experiment, andThe team was able to measure the electrical charge carried by each bee, as well as the amount of the main attractive chemical, benzaldehyde, released by the flowers in response to visits from bees.
To help distinguish between the response of a flower to the mechanical stimulus of a bee landing and the electrical stimulus, odor release was also measured in a subset of petunias that were touched with a grounded metal rod or ball of earth. Electrically charged nylon.
Flowers visited by free-flying bumblebees exhibited a significant increase in aromatic production. In contrast, flowers touched with an electrically grounded metal rod did not show such increases.
When touched with the electrically charged ball, with a charge equivalent to about five bee visits, the odor emissions from petunia flowers increased significantly again, roughly doubling the average odor volume.
Pollinators have long been known to carry positive electrical charges, but this is the first demonstration that plants use this to their advantage, Montgomery says.
‘Frequent visits by charged pollinators to a flower would cause charge accumulation, which could exceed a threshold for scent release. Therefore, the load could provide a useful indicator of how many pollinators are in the area, allowing the plant to assess the potential in real-time for pollen dispersal & rdquor ;, he explained.
“Current knowledge of the electrical charges carried by different species of insects is very low and the influence of electrical fields in all biological systems is often poorly understood and difficult to quantify.”
The project leader, Professor Daniel Robert from the University of Bristol, said: ‘This discovery reveals a previously unknown type of interaction between insects and plants, a world of elusive electrical signals that humans cannot detect. ‘
‘Insects are the dominant pollinators in agroecosystems and provide pollination services for many of our crops. The better we understand the interactions between pollinators and plants, the better we can preserve pollinating insects and ensure food safety, ”added Dr. József Vuts, Rothamsted Chemical Ecologist and co-author.
Reference study: DOI: 10.1007 / s00114-021-01740-2
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