What Are Killer Bees? The Science Behind Africanized Honey Bees
“Killer bee” is a movie name for a real insect. The bee people mean is the Africanized honey bee, and the science is a lot more interesting than the horror version. This post covers what the bee actually is, how it differs from the honey bees most Americans know, and why the nickname stuck. It’s one part of our larger guide, Killer Bees 101, which pulls the whole topic together. For the most common misconceptions, see Why Are They Called Killer Bees? 10 Myths vs. Facts.
The short answer
A killer bee is a honey bee. It is the same species as the bees beekeepers keep across the country, Apis mellifera. The difference is ancestry and behavior, not the bee’s size or a stronger venom.
University of Florida entomologists explain that African and European honey bees are the same species but different subspecies. The African subspecies at the root of the story is Apis mellifera scutellata, native to sub-Saharan Africa. In the Americas, “Africanized” refers to hybrids between that bee and the European subspecies beekeepers brought over centuries earlier.
So when someone says “killer bees,” they mean honey bees with a large share of African ancestry. They make honey, pollinate crops, and live in colonies with a queen, workers, and drones like any other honey bee. (Does their honey taste different? See Does Killer Bee Honey Taste Different?)
Where the “killer” label came from
The nickname comes from how hard these colonies defend the nest. The bee itself has nothing special about it.
UF/IFAS puts the numbers side by side. A disturbed European honey bee colony may send out 10 to 20 guard bees in response to a disturbance up to about 20 feet away. A disturbed Africanized colony may send several hundred, in response to a disturbance up to about 120 feet away. A European colony usually calms down within an hour or two. An Africanized colony may stay defensive for days. A disturbed European colony might deliver 10 to 20 stings. An Africanized colony can deliver 100 to 1,000.
That is the whole story behind the name. The danger is volume. A large number of stings at once can seriously hurt or kill a person or an animal, and pets or livestock that are tied up or penned can’t get away. We cover the medical side in How Dangerous Is a Killer Bee Sting?.
UF/IFAS also points out that “defensive” is the more accurate word than “aggressive.” These bees don’t go hunting for people. They react when someone gets too close to the nest. USDA’s Carl Hayden Bee Research Center in Tucson says it plainly: Africanized honey bees do not fly out in angry swarms to attack random victims. Stinging incidents happen when the nest itself is disturbed.
Same venom, different response
People are often surprised that Africanized venom is no stronger than European honey bee venom. UF/IFAS states this directly, and Texas A&M’s Apiary Inspection Service says the same thing: the venom is the same, and only the behavior can differ.
The University of Florida’s species profile goes further. Africanized bees are slightly smaller than European bees, so each one probably delivers a slightly smaller dose of venom. When deaths happen, it’s usually because of the number of stings, unless the person is allergic, in which case even one sting can be life-threatening.
Can you tell them apart by looking?
No. Africanized workers are roughly 10 percent smaller than European workers, according to UF/IFAS, but you can’t see that difference by eye. Labs identify them by measuring wing and body parts (morphometrics) or through genetic testing. We explain how in Africanized vs. European Honey Bees: How to Tell the Difference.
Other ways Africanized bees behave differently
Defensiveness gets the headlines, but beekeepers also notice these traits:
They swarm far more often
USDA ARS notes that a European colony typically swarms about once a year. An Africanized colony may swarm as often as every six weeks during swarm season. UF/IFAS puts it at 10 or more times a year.
They nest in small, odd places
Africanized colonies are smaller and accept much smaller cavities, often 1 to 5 gallons compared with the roughly 10-gallon cavity a European colony prefers. USDA lists water meter boxes, cement blocks, old tires, overturned flower pots, utility poles, junk piles, and house eaves. That’s why people run into them by accident.
They abscond
When food runs short or the nest keeps getting disturbed, an Africanized colony may abandon the nest entirely. European colonies rarely do this.
They store less honey
USDA and University of Arizona Extension both note that Africanized colonies tend to store less honey than European colonies. That makes sense for a bee that evolved where flowers bloom most of the year. It matters for honey, and we cover it in What Is Killer Bee Honey?.
They develop faster
UF/IFAS lists development times of about 14 days for an Africanized queen versus 16 for a European queen, and 19 to 20 days for an Africanized worker versus 21. A queen that hatches first can kill her rivals, which helps African genetics take over a mixed population.
Why a beekeeper cares
To a beekeeper, the Africanized honey bee is a management problem more than a monster. Colonies can be worked, and in much of South and Central America they are the standard honey bee. UF/IFAS notes that some South American countries are among the world’s leading honey producers largely because of African-derived bees. Working them takes heavier protective gear, more smoke, more space between hives, and a lot of respect.
For everyone else, the takeaways are simple. Leave colonies alone, don’t try to remove a nest yourself, and know what to do if bees attack. If you live in the North, also know that these bees are not established in your state. We look at that in Where Do Killer Bees Live? and Are There Killer Bees in Ohio?.
Where they came from, briefly
The African bees were brought to Brazil in 1956 to breed a honey bee better suited to the tropics. In 1957 some escaped quarantine, and their descendants spread across South and Central America and reached Texas in 1990. The full timeline is in The History of Killer Bees.
Frequently asked questions
Are killer bees a different species from regular honey bees?
No. Africanized and European honey bees are both Apis mellifera. They are different subspecies (or hybrids of subspecies), which is why they interbreed freely.
Is killer bee venom stronger?
No. UF/IFAS and Texas A&M both state that the venom is the same. The danger comes from the number of bees that respond and the number of stings.
Do killer bees chase people for no reason?
No. They defend the nest. Stinging incidents start when someone disturbs the colony, often without knowing it’s there, for example by running a mower or trimmer near a hidden nest. Once triggered, they may pursue a person a long way.
Are swarms of killer bees dangerous?
Swarms of any honey bee are generally docile because they have no brood or stored honey to protect, according to USDA ARS. Still, keep your distance, because you can’t always tell a resting swarm from a newly established colony.
Do killer bees make honey?
Yes. They are honey bees and make honey from flower nectar. See our Killer Bee Honey guide.
Related reading
Sources
- USDA ARS Carl Hayden Bee Research Center, “Africanized Honey Bees Overview”: https://www.ars.usda.gov/pacific-west-area/tucson-az/carl-hayden-bee-research-center/docs/africanized-honey-bees/africanized-honey-bees-overview/
- UF/IFAS EDIS ENY-147, “Differences Between European and African Honey Bees”: https://ask.ifas.ufl.edu/publication/IN784
- UF/IFAS EDIS EENY-429, “African Honey Bee, Africanized Honey Bee, Killer Bee”: https://edis.ifas.ufl.edu/publication/IN790
- UF/IFAS Solutions for Your Life, “Africanized Honey Bees”: https://sfyl.ifas.ufl.edu/natural-resources/africanized-honey-bees/
- Texas Apiary Inspection Service (Texas A&M), “Africanized Bees”: https://txbeeinspection.tamu.edu/public/africanized-bees/
- University of Arizona Extension AZ2011, “Honeybee Basic Biology”: https://www.extension.arizona.edu/publication/honeybee-series-honeybee-basic-biology
- USDA ARS, “Africanized Honey Bees: The March North Has Slowed” (1996): https://agresearchmag.ars.usda.gov/1996/mar/forum/