Do bees really get drunk?
Recently we were called over to a friends house to investigate why there was an unusual amount of bees in their yard. They had reported bees crawling around on their lawn and pavement, with many bees showing up dead.
Initially, we advised them that the unusual number of bees in their yard was as a result of the large Wandoo tree that was coming into full bloom. In Autumn, bees are frantically buzzing around trying to harvest and store whatever nectar they can. They do this to ensure they have enough honey to get through Winter.
What it means though is that we often get calls to investigate a ‘swarm’ of bees. More often than not it just turns out that the bees are super busy pillaging bushes or trees in people’s yards, and this activity is mistaken for swarming behaviour.
We left our friends house with the advice that the bees are just visiting, and they’ll be gone as soon as their tree stops flowering. The bee deaths were explained as being just the natural attrition of bees. They do after all only live about 6 weeks, and thousands die in the field every day.
Upon returning home it got us thinking. Maybe there is more to these bee deaths. These friends have lived under this tree for about 10 years and never noticed this before. So, as curious-minded folk, we took to the internet to see what info we could find.
It was at this stage that we recalled having read about ‘bee drunkenness’ that can result from the fermentation of nectar. In particular, the Wandoo tree (commonly known as a white gum) is known for instances whereby it has caused bee deaths due to fermentation.
We were curious to find out more about this…
What causes bee drunkenness?
As touched upon above, the fermentation of nectar can result in bees consuming alcohol which can be toxic to them. This fermentation process is thought to occur as a result of water mixing with the sugars in the plants nectar as well as wild yeasts. The combination of all these ingredients essentially creates a minuscule microbrewery for bees.
As most foraging bees are about 17 years and 11.5 months shy of the legal drinking age, alcohol is not particularly great for them. In much the same way as alcohol affects humans, bees lose the ability to fly (even though like some humans they think they can), and they end up sprawled out on the ground, dazed, confused and ultimately, many die from their intoxication.
Whatsmore, even if these bees do manage to return home, research has found that these bees often get rejected from their own hives. Yep, that’s correct, bees failing a once over and breath test at the hive entrance, get ‘bounced’ to the curb!
One-off binge drinking incident, or more widespread problem?
From our research into this, we’ve found that bees hitting the brews is more of an occasional and rare event, rather than a societal and systemic problem. It only occurs at certain times of the year when climatic conditions align with plant flowering events.
While drunk bees have been observed in various parts of the world, we have focussed our research on Australian plants that seem to result in these drunken events.
The most common plants that this occurs with are those that flower in late Autumn/early Winter. Lemon-scented Gums, Banksias and the Common Bottle-brush are among a few of our native plants that occasionally treat bees to some unexpected day drinking.
Many of the bees that die from this will probably go unnoticed. With larger populations of bees generally being out in bushland or on farms, a lot of the bee deaths will not be noticed.
That said, there have been cases where up to 90% of beekeepers bees have been killed off due to this alcohol poisoning.
This is certainly going to be of note to the beekeeper, who will perhaps assume these deaths are the result of a less natural dose of poison, such as an insecticide.
In urban areas, drunk bees will definitely attract more attention, particularly when they become a hazard to small children and those people allergic to bee stings. No one really wants uninvited drunks at their house, let alone hundreds of them all sprawled out on their lawn!
You may be wondering why this is not a more frequent event. Surely if it’s to do with nectar fermenting, then this would happen more than just occasionally, right?
Well, we aren’t scientists, but we looked into this a little further.
The science behind the phenomenon of drunk bees
On its own, nectar in flowers typically won’t ferment. The high sugar concentration effectively inhibits microbial growth, so microbes such as yeast cannot multiply within the nectar. This means that while nectar is exposed to wild yeasts, the sugar content within the nectar is sufficiently high enough to avoid any fermentation taking hold.
However, when subject to rainfall and high humidity levels in the surrounding environment, the nectar can take on moisture and become diluted. The natural yeasts can then begin to overcome the preserving effects of the high sugar content, and they can begin the fermentation process.
One would then assume that this would become more of a problem in Winter, due to the increased relative humidity and higher rainfall period. Luckily for the bees though, this wetter period coincides with shorter daylight hours and colder weather, which means there are fewer bees out foraging during this time.
As mentioned, Autumn can be a particularly bad period for drunkenness. Spring can also be a boozed up time for bees as well. This is because these are periods where warm weather is interspersed with rainfall and higher humidity. The humidity will increase the rate at which nectar takes on moisture, while the warmer weather can promote the rate at which nectar ferments.
Do drunk bees affect honey quality?
While we would normally steer clear of food produced by people who drink excessively on the job, we are going to assume that drunk bees aren’t producing poor quality honey.
We have never experienced the problem of honey fermenting in our hives, at least not from fermented nectar coming into the hive.
There are instances where uncapped honey can ferment in the hive, but that is normally only going to occur in a poorly managed hive where the moisture levels are high and the bee coverage is poor.
It is recorded that bees actually reject the drunk bees returning to the hive, so we believe this would safeguard honey stores from being contaminated by the fermenting nectar.
Additionally, a lot of the bees harvesting the fermented nectar simply won’t return to the hive, so while this is unfortunate, it does shield the rest of the hive from being affected.
Hopefully the above has given you some understanding of the rather interesting phenomena of drunk bees.
Interestingly, bees are not the only creatures affected. There have even been reports of birds eating the fermenting flowers and effectively getting drunk as well…
Thanks for reading. We hope you got something out of this article and furthered your bee knowledge!
If you have ever witnessed this yourself, or are keen to share your thoughts, please comment below.