Tag Archive for: killer bees usa

Africanized honey bees, the bees nicknamed “killer bees,” are established across the southern edge of the United States. They have not moved into the colder northern states, and the scientific explanation is mostly climate. This post covers where they live, how they got there, and why the spread slowed. It’s part of our Killer Bees 101 guide.

The short answer

As of the most recent extension summary we found (University of Florida, citing data through 2012), Africanized honey bees had been found in Texas, California, New Mexico, Arizona, Oklahoma, Louisiana, Arkansas, Alabama, and Florida. A 2004 USDA Agricultural Research Service report also lists southern Nevada, plus Puerto Rico and the U.S. Virgin Islands.

“Found in” and “established everywhere in” are different things. In several of those states the bees occupy only the southern counties. Florida’s extension service, for example, describes them as established in the southern half of the state.

How the range grew

• 1990: The first Africanized swarm in the U.S. was found on October 15, 1990, in a USDA trap outside Hidalgo, Texas.
• 1993: First seen in Arizona, according to University of Arizona Extension. By 1997 they had reached Yavapai County in central Arizona, and today they’re recorded statewide.
• 1996: USDA reported them in parts of Texas, Arizona, New Mexico, California, Puerto Rico, and St. Croix.
• 2001–2003: Florida documented them near the Port of Tampa in 2001, and by 2003 they had established colonies around Tampa, according to UF/IFAS.
• 2004: USDA listed five states (Texas, Arizona, New Mexico, southern California, and Nevada) plus Puerto Rico and the U.S. Virgin Islands.
• 2006: Texas had detected them in 163 of its 254 counties, according to the Texas Apiary Inspection Service.
• 2012: Nine states, per the University of Florida summary above.

The full backstory, from Brazil in the 1950s to the Texas border, is in The History of Killer Bees.

Why they stopped moving north

In South and Central America, Africanized bees spread an estimated 200 to 300 miles a year, according to UF/IFAS. In the U.S. the advance slowed sharply, and researchers point to climate.

Cold winters

These bees come from tropical and subtropical Africa, and they store less honey than European bees. UF/IFAS says plainly that they don’t survive temperate climates as well as European bees do. UF/IFAS and University of Arizona Extension both describe them as established only below about 34° north latitude. For reference, that line runs roughly through Los Angeles, just north of Phoenix, central New Mexico, north Texas near the Oklahoma line, southern Arkansas, and the northern parts of Mississippi, Alabama, and Georgia. In the southern hemisphere they also stalled near 32° south. For the Midwest angle, including Michigan and Indiana, see Are Killer Bees Moving North?

Rainfall

In 2004, USDA ARS entomologist José Villa reported a strong correlation between heavy, even rainfall (more than 55 inches a year, spread through the year) and an almost complete barrier to their spread. He was careful to say this was a correlation, not a proven cause, but it helps explain why parts of the humid Southeast filled in more slowly than the dry Southwest.

Competition and hybridization

USDA noted in 1996 that interbreeding with resident European bees, diseases, parasites, and cold weather may all be slowing the advance. A strong population of European bees, kept gentle by beekeepers who requeen regularly, may be an area’s best buffer.

What about the northern states?

Africanized bees are not established in the Midwest or Northeast. Ohio State University extension specialists have said there are no Africanized bees in Ohio. In 2024 OSU tested a suspected “killer bee” colony from southwest Ohio and found it was an ordinary western honey bee colony. We cover the Ohio question in detail in Are There Killer Bees in Ohio?.

So how do people up north run into them? Occasionally a swarm hitches a ride on cargo, or a beekeeper buys package bees or queens from a southern supplier. If you’re a northern beekeeper ordering queens or packages, ask the supplier where the stock was raised and how they keep it European. A single stray colony isn’t an established population, and a northern winter is hard on bees adapted to the tropics.

Will climate change push them north?

Possibly, and it’s reasonable to ask. If the cold limit is real, milder winters could let the range creep north over time. We found no current federal forecast or 2020s survey that puts numbers on it, so we won’t guess. What we can say is that the bees’ advance has been slow and uneven, and decades of watching have not shown them sweeping into northern states.

What this means for you

• In the Southwest, Texas, or southern Florida: Treat every wild honey bee colony as potentially Africanized. Bee-proof your property, check before mowing, and learn what to do if bees attack.
• In the North: Your stinging-insect problems are much more likely to be yellowjackets, paper wasps, and hornets than Africanized bees. A defensive honey bee colony in a wall still deserves professional help. See Bee & Wasp Removal.
• If you buy honey labeled “killer bee honey”: It has to come from a region where these bees actually live. See What Is Killer Bee Honey?.

Frequently asked questions

Which states have killer bees?

University of Florida’s summary (data through 2012) lists Texas, California, New Mexico, Arizona, Oklahoma, Louisiana, Arkansas, Alabama, and Florida. USDA also lists southern Nevada, Puerto Rico, and the U.S. Virgin Islands.

Are killer bees in every part of those states?

No. In many states they are limited to southern areas. Arizona and much of Texas are the most heavily Africanized.

How far north can killer bees live?

They’re currently established below roughly 34° north latitude, according to UF/IFAS and University of Arizona Extension.

When did killer bees arrive in the U.S.?

October 15, 1990, near Hidalgo, Texas, according to USDA ARS.

Is there an official current range map?

USDA ARS has published county-level spread maps, but we did not find a federal map updated in the 2020s. Check your state’s department of agriculture or apiary program for local status.

Related reading

• Are There Killer Bees in Ohio?
• The History of Killer Bees
• Killer Bees 101 hub

Sources

• UF/IFAS EDIS EENY-429, “African Honey Bee, Africanized Honey Bee, Killer Bee” (distribution section): https://edis.ifas.ufl.edu/publication/IN790
• UF/IFAS EDIS ENY-170, “Living with the African Honey Bee”: https://ask.ifas.ufl.edu/publication/IN1205/pdf
• USDA ARS, “The Latest Research on Africanized Honey Bees” (2004): https://www.ars.usda.gov/news-events/news/research-news/2004/the-latest-research-on-africanized-honey-bees/
• USDA ARS, “Africanized Honey Bees: The March North Has Slowed” (1996): https://agresearchmag.ars.usda.gov/1996/mar/forum/
• Texas Apiary Inspection Service, “Africanized Bees”: https://txbeeinspection.tamu.edu/public/africanized-bees/
• University of Arizona Extension, “Feral Honeybees” (Backyard Gardener #119, 2023): https://extension.arizona.edu/sites/extension.arizona.edu/files/attachment/FeralHoneybees.pdf
• University of Arizona Extension AZ2011, “Honeybee Basic Biology”: https://www.extension.arizona.edu/publication/honeybee-series-honeybee-basic-biology
• Ask Extension (Ohio State), “Have Africanized bees entered Ohio?”: https://ask.extension.org/kb/faq.php?id=265942
• Ohio State University BYGL, “Myths and facts – Africanized honey bees”: https://bygl.osu.edu/node/2431