Honeybees, Lavender and DNA
Lavender is one of the most familiar and popular aromatherapy scents around the world.
It is quite accepted by now that lavender calms humans, bringing peace to replace anxiety and stress. It is especially helpful when it is time to sleep so we can relax into a deep and restful slumber.
But is lavender even more powerful than previously understood? According to a video by ABC Science, Australian research from 2016 indicates that not only does lavender help bees to make new memories, it changes their mood and behavior and even alters their DNA. Can it have the same effect on people?
This fascinating 10:40-minute long video is about honeybees, scents and their DNA.
Beekeeper William Kwan at Monash University in Victoria, Australia, explains that bees are perfect research subjects due to their keen olfactory sense of smell. Charles Claudianos, Professor of Neurogenetics and Development at Monash University, finds the bee brain particularly interesting because although it is anatomically different to the human brain the fundamental mechanics of how it works are similar. Humans and bees usually enjoy the same scents, like roses and lavender.
Lavender has been used as a calming agent for humans, their pets and animals including bees in France and other parts of Europe for ages. In fact, bees see lavender as a beneficial compound.
One scent that bees don’t like, and it makes them aggressive, is bananas. Beekeepers, according to William Kwan, can spread a banana peel across the top of the hive when they want to clean it out. A compound in the banana called isoamyl acetate is the very same as that which is the honeybees’ alarm pheromone. This knowledge can be used to see how it affects memory and aggressiveness in honeybees in the laboratory.
Professor Claudianos wanted to observe the response of bees to lavender, so he took bees between 10-14 days old, without much exposure to the environment, and put them into a small device where only their heads poked out. As a conditioning experiment, the scent of lavender was blown gently across their antennae and immediately afterwards the bees got a drink of sugar water. After a few times they associated lavender with the reward. Within a day or two the bees put out their tongues in anticipation of the reward, showing a memory was formed. Weeks and months later this still worked. Given their short lifespans, this shows it became a significant part of their lives.
Is this reaction just a learned response or do bees have an innate response to the scent? While looking at memories and how they are formed, researchers noted there was a preference for certain odors. It just so happens that one of these compounds modifies the aggressive response in a bee.
Another experiment involved a black feather brushing against them. Bees respond adversely to black because they feel threatened by it. They started a stinging behavior and as they grew more aggressive they released the pheromone that smells like banana.
Dr. Claudianos isolated the two scent molecules that calm bees: 2-phenylethanol, the key component of rose scent, and linalool, a common floral scent found in many plants, including lavender. They then replicated the experiment in the field.
The laboratory experiment and the hive experiment in the field returned the same results. These two compounds have a significant effect on calming bees. After confirming the effect of scents on mood regulating and memory making they checked the effect of scents on DNA.
In 2006 Dr. Claudianos and his team were part of a large international team that sequenced the honeybee genome. It was much smaller than other genomes they had previously examined. They had a theory that the olfactory cues treated by scents like lavender were directly linked to the expression of certain bee genes.
The genome interacts with the environment constantly and we now know that these processes involve the science of epigenetics. Not all genes are active. Some are turned off. Epigenetics is about how genes are switched on and off as a function of the environment and involves certain chemical processes like methylation. Environmental influences cause certain molecules to attach to DNA to silence particular genetic expressions. In this way different genetic traits can be expressed in the host.
Dr. Claudianos used cancer drugs designed to stop the methylation process so they could see what the bees would remember if they were unable to make epigenetic changes to their DNA. A drop of the drug was put on the bee's thorax and it was absorbed. Then the bee was put into the classic memory learning approach. The methylation inhibitors (cancer drugs) significantly affected long term memory. Bees found it almost impossible to make long term memories if they were unable to make epigenetic changes to their DNA.
Could there be implications for human mental health? Bees are a great model for human research. When one has memory problems one of the first things to go is the sense of smell. What effects do these scents have on the human brain? Experiments are ongoing, and Professor Claudianos expects to see changes in the neurotransmitter system when a person exposed to lavender reacts in the same way the bees reacted, and that will be very exciting.
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