By Dr. David T. Peck, Betterbee's Director of Research & Education. Dr. Peck earned a Ph.D. in the Department of Neurobiology and Behavior at Cornell University, overseen by Professor Tom Seeley. After earning his doctorate, David continued to work at Cornell as a postdoctoral researcher, with a particular focus on varroa/bee issues in mite-free Newfoundland, Canada, as well as in Madagascar, where varroa mites were accidentally introduced only a few years ago.
To most beekeepers, honey bees are a source of wonder, excitement, and amazement, as well as a source of honey. But for some non-beekeepers," honey bees are just flying stingers and they want nothing to do with them. Why and how do honey bees sting? What are they injecting when they do? This installment of our bee biology series explores the most infamous part of the honey bee’s body: the sting.
From: The Anatomy of the Honey Bee, R.E. Snodgrass, 1910
What is a sting?
A sting, or stinger (either is acceptable) is part of the female reproductive organs of a honey bee. In some species of ants, bees, and wasps (collectively called the “Hymenoptera”) females sometimes have a long pointed lance on the tip of their abdomen. They may simply use these organs to lay their eggs, or they may have a highly specialized role. For example, wood wasps in the genus Sirex and the genus Rhyssa use their long stingers to bore holes in solid wood, injecting their eggs deep into a tree, and also injecting a mix of wood-eating fungus that will help provide food for the young wasps when they hatch. But for most of these insects, the sting is a weapon used for offense, defense, or both.
Why sting?
Predatory insects sting to kill their prey - if the prey is lucky, that is. Some predators like jewel wasps will catch a cockroach, sting into its brain and inject a cocktail of chemicals, and turn it into a half-paralyzed zombie. The wasp then lays an egg in the roach’s body, and the roach remains alive as the wasp larva eats it from the inside out.
Herbivores like bees typically sting only to defend themselves. Solitary bee species may be able to sting, but they don’t sacrifice their lives when they do so, since the high cost of dying beats any benefit they may get from delivering extra venom Only worker honey bees, who have no hope of laying any eggs themselves, have completely adapted their stings into a kamikaze weapon. Since a colony can spare an individual worker (or a hundred) the bees can give up their lives to plant a potent venom-injection device directly into the skin of their enemies.
From: The Anatomy of the Honey Bee, R.E. Snodgrass, 1910
Sting anatomy
Worker honey bee stings have a few key parts. A stylet, a stabilizing rod with a groove down the middle (F in the diagram) holds two barbed lancets (tips shown in E in the diagram). The lancets are harpoon-like spikes that pierce and dig into the flesh of whatever the bee stings. The lancets are connected to muscles that contract in an alternating pattern to work the lancets deeper and deeper into the sting’s victim. As the barbed lancets slide back and forth past one another, their movement is lubricated by the venom from the bee’s venom gland. Even when the bee’s body has long since been smashed or scraped away, the venom glands, muscles, and lancets are working to punish whatever creature was foolish enough to tangle with a bee colony. This is why stings should always be removed by scraping them off of the skin instead of pinching them out: Pinching will squeeze the contents of the venom gland into the wound while scraping can pull the sting apparatus safely away from your skin without releasing excess venom.
Common wisdom tells us that honey bees die after they sting, though this is only true if they are fighting against creatures with tough, elastic skin that will catch and hold the barbs of the sting. Creatures like mammals, birds, or other vertebrates. If a honey bee stings another insect, she can inject a few droplets of venom and then pull her sting out of her victim and carry on with her day. When a guard bee stings a robber bee, a bothersome bumble bee, or any other invading insect, she will usually live to tell the tale, though her target won’t.
Chemical warfare
The venom cocktail of a worker bee is a potent mix of compounds meant to hurt or even kill the bees’ enemies. Analyzing the contents of honey bee venom shows that a protein called melittin makes up just over half of the dry weight of the venom. This compound causes pain and damage when it is injected into our bodies. The next most common compound (about 12%) is an enzyme called Phospholipase A2, which promotes the breakdown of molecules in the membranes of our cells. The remaining compounds are mostly other enzymes, each only making up a few percent of the venom. These compounds also cause pain, damage, and inflammation at the site of the sting. Read more about the chemistry of bee venom here.
In addition to venom, there is another chemical cocktail at play here: the alarm pheromones released when a bee stings. As the tip of the abdomen is torn off, a bee’s internal body fluids leak out, and these contain a potent mix of chemicals that other bees can easily smell. The alarm pheromone is made up of many compounds, but one important one is isoamyl acetate, (which by random chance smells to humans like bananas or pears.) The odor of these various body fluids attracts the attention of other bees, and primes them to sting as well. This can turn one sting into a cascade of follow-up stings that can chase away all but the most determined pests. This is why we must be careful not to smash bees during hive inspections, since each drop of bee guts exposed to the air releases more alarm pheromone that can increase the chance of subsequent stings.
Another advantage of alarm pheromones is that each sting serves as a chemical flag to summon more bees to an exposed body part on their target. A human without a bee suit has a lot of exposed skin for guard bees to sting, but a black bear has very little skin that isn’t covered in thick fur. A bee planting her sting into a bear’s nose, or ear, or lip can bring more guards directly to that same vulnerable body part to inflict maximum damage on the bear. When bees sting you, or if bees are smashed, always smoke the affected area to try to cover up the smell of the alarm pheromone. In addition, if your gloves or pants experience a large number of stings, don’t think that a day away from the apiary will remove all of the alarm pheromone smell. Make sure to wash anything that makes contact with a bee sting before bringing it back to the apiary, or you may unleash another round of stinging.
The author’s wife once bought a new brand of dish soap, and upon opening the bottle the author immediately felt the hairs on the back of his neck stand straight up. The fragrance in the soap was mostly isoamyl acetate, and the author’s experience with bee stings and alarm pheromone caused an unintentional physiological panic response as soon as he smelled it. The smell of that much “alarm pheromone” told his subconscious that a huge number of bee stings were likely. He found using the soap to be so unpleasant that he gave his wife an ultimatum: discard the brand-new bottle of soap, or she would have to wash all of the dishes until the bottle was empty. The bottle was gone that afternoon, replaced with an unscented brand.
A royal dagger
Of course, not all bees are alike, and neither are their stings. While worker bees have barbed stings and (usually) die if they sting in defense of their hive, queens are playing an altogether different game. A queen’s sting is not barbed, and she will almost never use it defensively unless she’s being roughly handled by a very clumsy beekeeper. If she does sting, she will inject venom but won’t leave her sting behind. This is because her sting isn’t meant for colony defense but instead is meant to kill rival queens. When a virgin queen first emerges from her cell, her first order of business is to find and kill any other young queens in the colony. Eventually, after much grappling and stinging, there will be just one remaining queen, who will eat and mature until she’s ready to take her first mating flight. Once the queen has stung her rivals, she is unlikely to sting again for the rest of her life, though she is always armed with her sting in case the need arises.
“Aggressive” or “Defensive”
Beekeepers know that some colonies are a little more “peppery” or “feisty” than others, but no matter how irritable our bees are, it’s not proper to call the bees “aggressive”. Bees won’t leave the hive to seek out trouble, and they gain nothing by getting in a fight away from the hive. Instead, we must describe these colonies as highly “defensive”. Using this kind of language highlights why the bees are stinging or threatening to sting. It’s not that they’re picking a fight; they’re just ready and willing to sacrifice their lives in defense of their colony, and some colonies feel threatened more easily than others do. Sometimes this is genetic, and sometimes it’s the product of experience. A hive that is regularly visited by bears or skunks is usually much more likely to sting than one that has lived a peaceful life.
Even though bee stings can be unpleasant or even scary, it’s important to remember that bees sting when they are concerned for the safety of their families, and not just to ruin our days.
