Sep 02, 2021
Posted by: Amanda Kreklau
At Perpetual Pollen, we are all about the bees. But we also like to give the people what they want. And what do the people want?
Google search “cute animal videos” and you get over two billion results. That’s more than Rihanna. That’s even more than chocolate. (Okay, okay, go ahead and look, but be sure to come back!) And they’re not just for kids—everyone goes wild for adorable animals playing, eating, or literally just existing.
Not surprisingly, there are quite a lot of videos featuring animals grooming each other. I say it’s not surprising because I know one of the few things that has always instantly grabbed the attention of any room full of people is two cats grooming each other. It’s adorable. Just imagine: there have been over one million views of this video of two horses grooming each other.
Humans are intensely curious creatures, and we love to learn all about the things we find interesting—or adorable. As you can imagine, those of us who want to save the bees want to know everything there is about the species. Point being, it turns out that it’s not just mammals and birds that engage in social grooming behaviors. Bees do, too! Actually, most social animals do.
For many animals, especially primates but also birds, horses, and cows, grooming serves social purposes such as emotional bonding and comfort. The jury is still out on whether bees experience emotions the way mammals do, but as we found out, bee grooming behavior is an absolutely essential part of hive health.
Why do honey bees groom?
Beehives are as close to a closed system as you’ll find in nature. Only some occupants leave the hive daily, and only those bees (and the pollen they carry back) are supposed to enter. Hives are densely populated, with tens of thousands of bees living together in a single hive. The health of the entire hive depends on as few contaminants as possible getting inside. Typically bees protect their hive with resins they carry back from plant sources, which are naturally antimicrobial—good for defending against bacteria, viruses, and fungi.
Honey bees groom themselves for a reason that has little to do with cleanliness, though: they’re tiny. As it turns out, many insects spend quite a lot of time grooming, and it makes sense when you think about it. To an insect, specks of dust, dirt, and pollen are much more than tiny irritants we humans may not even notice. Not only are the particulates much larger in comparison, insect bodies are often highly sensitive—contaminants that put barely a spot on our skin could prevent a bee from seeing or smelling, or even detecting their physical position in space.
Why don’t honey bees bathe?
Most humans consider water a vital part of their own grooming routines. Most insects aren’t able to use water that way, due to, well, a lot of sciency reasons that are better explained here (seriously, check this out because it is fascinating and goes way beyond bees). The short answer is surface tension. Water molecules are strongly attracted to each other, so molecules on the surface of a body of water will be physically drawn downward toward the water molecules below. This creates a force known as surface tension. When certain winged insects land on water, their body may break the surface, but their wings—being extremely light—won’t. Instead, the wings will become “stuck” to the surface of the water, as they are drawn downward through the power of surface tension, and the insect will be unable to fly away. Some very tiny insects can even get caught inside a water droplet and drown.
So how do honey bees groom?
Instead of using water, honey bees use friction. Honey bees have literally millions of tiny hairs on their bodies, which are useful for carrying large amounts of pollen back to their hives—efficiency! These hairs are also used for self-grooming, as bees will use their legs to “comb” their eye area.
How does learning about bee grooming help us save the bees, anyway?
At this point you might be thinking, “if bees don’t groom for the sake of cleanliness, how exactly is it essential to hive health?” Enter that pest we love to hate: the varroa mite. By now you’re probably familiar with varroa destructor, the parasitic mite that can destroy a honey bee hive from the inside out. You may remember that varroa mites infest hives by hitching a ride on the backs of bees returning home.
An individual bee does have some ability to fight off a mite using its mandibles (jaws) and its legs—if the mite is located in the right place. But just like that one spot in the middle of our back so many of us can’t reach (the reason backscratchers—and spouses—were invented), often the varroa mite attaches somewhere a bee can’t get to itself. Evolution to the rescue, perhaps literally! Scientists have been studying social bee grooming since 1945, when the “grooming invitation dance” was identified by bee biologist Mykola H. Hadak. One Cornell University study suggests that the dance, and social grooming, likely grew from the natural motions of self-grooming behavior. If you think about it, this is actually very relatable. How many times have you watched someone struggle to do something and then just offered to do it yourself?
So-called allogroomers (that is, bees that groom other bees) are so important to the health of the hive that they’ve actually evolved to take on the role. One study found that allogroomer bees have more robust immune systems, probably to help them ward off infection from greater exposure to viruses and bacteria through grooming behaviors. And as for their efficacy against the varroa mite? An Argentinian study found that bees which were naturally mite resistant engage in more frequent grooming behaviors. The scientists behind that study concluded that the best way to develop natural mite resistance in honey bee populations was to work alongside natural selection to select for those bees that naturally groom each other more.
That’s something only beekeepers can do, of course. But there are other possibilities. That Cornell study also found that grooming invitation dances could be prompted by “puffing” a bit of chalk dust onto the bees. Those of us serious about saving the bees might, at this point, be thinking, “Wouldn’t it be nice if there was something safe and easy we humans could do to encourage this awesome behavior for the health of our local honey bees?”
Well . . . stay tuned.