Bumble Bee — Fact Sheet

Scientific names: Bombus pensylvanicus (American bumble bee), B. impatiens (common eastern bumble bee), B. griseocollis (brown-belted bumble bee), B. fraternus (Southern Plains bumble bee), B. bimaculatus, B. fervidus, B. variabilis, and the Sonoran bumble bee Common names: Bumble bee, bumblebee, humble bee (archaic) Family: Apidae (genus Bombus) Status in the San Antonio / Boerne corridor: Native, welcome, in decline — conservation-priority species

At a glance

Identification

Bumble bees are the fat, fuzzy, slow-flying bees that everyone likes. They are unmistakable to most people — big, round-bodied, loud, covered in dense hair head to toe.

The single biggest confusion is bumble bee vs. carpenter bee. Both are large, both have yellow-and-black patterning at a glance, and both are common around Texas homes. The rule:

• Bumble bee: fuzzy all over, including the abdomen
• Carpenter bee: fuzzy thorax, shiny bare black abdomen ("shiny on the hiney")

Bumble bees also have pollen baskets (corbiculae) on their hind legs — you'll often see them returning to the nest with bright yellow or orange pollen packs the size of BBs strapped to their legs.

Texas hosts nine bumble bee species, with diversity highest in the eastern half of the state and decreasing as you move west into the Chihuahuan Desert. In the San Antonio and Hill Country corridor, the species you are most likely to encounter are:

• American bumble bee (B. pensylvanicus) — once the most common, now a conservation-priority species in dramatic decline
• Brown-belted bumble bee (B. griseocollis) — yellow thorax with a brown band, common in gardens
• Sonoran bumble bee — western distribution, overlaps with the western edge of our territory
• Southern Plains bumble bee (B. fraternus) — historically common in Texas, also in decline

Biology and behavior

Annual cycle — the solitary queen's year

Bumble bee colonies are annual. Unlike honey bees, they do not overwinter as a functioning colony. Every year is a fresh start. Here is what that looks like in the San Antonio area:

• Late winter / early spring: A mated queen who spent the winter hibernating alone — typically underground, a few inches deep in soil — emerges. She has not eaten anything since the previous summer. She is hungry.
• Spring: The queen forages, eats to rebuild her body fat and develop her ovaries, and searches for a nest site. The site is almost always an existing cavity — an abandoned mouse or vole burrow is the overwhelming favorite.
• Nest founding: The queen builds a small wax "honeypot" to store nectar, lays her first batch of eggs, and does every single job herself. She is worker, forager, nurse, guard, and builder simultaneously.
• Brooding the eggs: This is one of the most remarkable parts of bumble bee biology. The queen incubates her eggs like a bird. She sits directly on the wax-capped egg clump and maintains a body temperature around 30°C (86°F) by shivering her flight muscles. There is a bare patch on the underside of her otherwise fuzzy abdomen that lets heat pass directly to the eggs. If the brood cools below 30°C, larval development is stunted.
• First workers emerge: About 4–5 weeks after egg-laying begins. These are smaller, non-reproductive daughters of the queen. They immediately take over foraging, and the queen settles into full-time egg-laying.
• Colony growth: Through summer, the colony grows, typically reaching 50–500 workers at peak (with extreme variation by species).
• Late summer: The queen begins producing new queens (gynes) and males. This is the reproductive phase.
• Fall: New queens and males leave the nest. They mate — males die shortly after, or die of cold when fall temperatures drop. Only the newly mated queens survive. They find a hibernation spot, usually in soil, and wait out the winter.
• The old queen and all workers die. Every year. The nest is not reused.

Why a queen's early spring is so hard

Before her first workers emerge, a foundress bumble bee is on an exhausting schedule. Research on Bombus terrestris has documented that a founding queen may need to visit as many as 6,000 flowers in a single day to gather enough nectar to maintain the heat needed to brood her eggs. Every foraging trip means the brood cools down while she's gone, so the trips have to be short. A late spring with poor flower availability can doom a queen who would otherwise have founded a healthy colony.

This is why every decent Hill Country pollinator garden matters. Early-blooming native plants — mountain laurel, Texas redbud, agarita, early salvias — are disproportionately valuable because they feed foundress queens at exactly the moment of peak vulnerability.

Buzz pollination — the bumble bee's specialty

Bumble bees are the specialists in buzz pollination. A bumble bee lands on a flower that holds its pollen tightly (tomato, pepper, eggplant, blueberry, cranberry, and many native wildflowers), grips the anther, and vibrates her flight muscles at a specific frequency — without moving her wings. The vibration shakes the pollen loose in a cloud.

Honey bees cannot do this. It's not in their behavioral repertoire.

For commercial greenhouse tomato production around the world, entire bumble bee colonies are purchased and placed inside greenhouses because without them, the tomato flowers don't pollinate. A multi-billion-dollar greenhouse industry is built entirely on one genus of bee doing one specific trick honey bees cannot do.

Bumble bees and temperature — the thermostat insects

Bumble bees can fly in cold weather that grounds every other bee. They can raise their body temperature above ambient by shivering their flight muscles, a behavior called endothermy. A bumble bee can warm itself to 30°C before takeoff even on a 50°F morning, and this is why you see fat bumble bees bouncing around gardens on cool spring days when honey bees are still inside the hive.

This also explains their fuzzy coat. The dense hair isn't for looks — it's thermal insulation that lets them hold on to the heat they generate. The same adaptation lets them live at high altitudes and high latitudes that honey bees can't reach.

The "pollen constancy" habit

Bumble bees tend to visit the same species of flower over and over on a single foraging trip, a habit called pollinator or flower constancy. They'll work a patch of a given plant for minutes at a time, often ignoring other blooming species right next to it. This behavior makes them genuinely better cross-pollinators than bees that flit randomly between species. For the plants involved, a bumble bee is the ideal pollinator because her pollen loads are mostly one species' pollen, which is exactly what that plant's stigma needs.

Bumble bee intelligence — what the research actually shows

This is the section where bumble bees stop being cute garden insects and start being genuinely unsettling.

Over the last 20 years, research primarily from Lars Chittka's lab at Queen Mary University of London has established that bumble bees have cognitive abilities that bee brains should not, by any reasonable expectation, possess. A partial list of documented capabilities:

• They can be trained to solve a two-step puzzle box by watching another bee do it first. Published in Nature in 2024. This is social learning of a complex behavior that no single bee could figure out alone, and it is genuinely the beginning of something like culture in an insect.
• They learn to pull strings to get food, and other bees watch them and copy the behavior.
• They've been shown to roll balls into a target for a reward — a task with no natural analog. Bees trained to watch demonstrators do this then improved on the demonstrated technique. They weren't just copying; they were innovating.
• They understand the concept of zero — an ability previously documented in primates, corvids, and a handful of other animals, and a concept that human children don't grasp reliably until age 4 or so. Honey bees share this ability too; bumble bees are easier to test.
• They can count to four, and reliably rank "nothing" as less than "one."
• They socially transmit foraging techniques, including learned nectar-robbing behavior — one bumble bee figures out she can cut a slit at the base of a flower and steal nectar without pollinating, and her nestmates pick up the trick.
• They respond to damaged appendages in ways that suggest a pain-like experience, which has become a serious animal welfare research topic in the last five years.

Why bumble bees matter so much for cognition research: they're easy to track individually, they can be kept in the lab year-round, and their colonies are small enough that researchers can paint-mark every individual and study learning across an entire colony. They've become, along with honey bees, the main insect model for research on intelligence at the edges of what small brains can do.

Every bumble bee you see on a Texas lantana has a brain with fewer than one million nerve cells — fewer than the retina of a single human eye. Within that brain, the bee is running a navigation system, a pollen-constancy decision rule, a nest-to-target mapping function, and (apparently) a system for understanding zero.

Local context — San Antonio and the Hill Country

Bumble bees are common on residential landscape plants across the entire region, from downtown San Antonio gardens to Boerne pollinator beds to the larger-lot pollinator habitats of Bulverde and Spring Branch. The plants that reliably produce bumble bee foragers include:

• Mealy blue sage (Salvia farinacea) — the single best bumble bee plant in Central Texas
• Cenizo / Texas sage (Leucophyllum frutescens)
• Lantana (native and cultivated)
• Turk's cap (Malvaviscus arboreus)
• Black-eyed Susan, Mexican hat, and other native composites
• Tomato, pepper, eggplant plantings — they'll buzz-pollinate home vegetable gardens

Nest sites on residential property are usually:

• Abandoned rodent burrows in landscape beds
• Underneath garden shed floors or deck substructures
• In compost piles (warm, humid — ideal)
• In overgrown grass at the edge of acreage properties
• Rarely in wall voids, but it does happen in older Hill Country homes with rock exteriors

The conservation issue

The American bumble bee (B. pensylvanicus) — once one of the most common bumble bees in Texas — has declined precipitously across most of its range over the last 30 years. The US Fish and Wildlife Service conducted a status review and the species is under consideration for Endangered Species Act listing. Contributing factors include habitat loss, pesticide exposure (particularly neonicotinoids), pathogen spillover from commercial bumble bee colonies used in greenhouse pollination, and climate change.

When we advise clients in Boerne, Fair Oaks Ranch, and the larger-lot Hill Country communities, bumble bee nest removal should essentially always be the last option. A nest found in a compost pile or garden bed is going to die off naturally by November anyway. For properties where the nest is in a genuinely problematic spot — inside a doorway, in heavy foot-traffic area, near a child's play zone — we do removals. For everything else, we recommend education and wait-it-out.

Risk to humans and pets

Low. Bumble bees are the least aggressive social bees you will encounter in Central Texas. They sting reluctantly, and then only in close-range defense of the nest. Foragers away from the nest are functionally harmless; you can put your face inches from a bumble bee on a flower and she'll ignore you.

The sting itself rates 2.0 on the Schmidt Pain Index — comparable to a honey bee, described as "like a match head that flips off and burns on your skin." Because the stinger isn't barbed, the bee doesn't die, and individuals can sting multiple times if actively harassed. But even within feet of the nest, bumble bees give clear warning signals (buzzing loudly, flying erratically in front of the intruder) before actually attacking.

Treatment approach

• First recommendation: leave it alone. The nest will be gone by fall. Mark the entrance with a stake so the homeowner knows where to avoid mowing. Come back and tell us how it went.
• Second option: relocate. If the nest must be moved, it can sometimes be done at dusk when workers are inside. Seal the entrance, dig out the cavity contents, move the nest to a protected area away from human traffic, and reopen. Success rates are mixed.
• Last option: lethal removal. Only when the nest location is genuinely incompatible with human or pet safety. Dust applied to the entrance at dusk, entrance sealed.
• Allergy considerations: If a known-allergic individual lives on the property, the risk calculation changes and removal becomes the correct call.

Odd, funny, and genuinely true

• Bumble bees warm flowers for other bees. Research has documented that when a bumble bee lands on a flower for a few seconds of warming before nectar-gathering, she raises the flower's internal temperature by a measurable amount. Other pollinators who arrive soon after get a warmer flower, which makes the nectar easier to access. The bumble bees probably aren't doing this on purpose, but the effect is real.
• Bumble bee queens are literally huge. A large American bumble bee queen can weigh over a gram — 10 to 20 times the weight of a honey bee worker. Standing still next to a foraging queen on a salvia in March is a thing you don't forget.
• The phrase "according to aerodynamics, bumble bees shouldn't be able to fly" is a myth — but it has an origin. In the 1930s, a French engineer applied fixed-wing-aircraft equations to a bumble bee and concluded their lift should be insufficient. He was using the wrong model. Bumble bee wings generate lift through complex vortex patterns, not fixed-wing airflow, and modern aerodynamics has no trouble with them. But the myth that "science says they shouldn't fly" stuck for 80 years.
• Bumble bees can learn to roll a ball for a reward. In 2017, researchers at Queen Mary University of London showed bumble bees not only learn a ball-rolling task for sugar water, but when shown a demonstrator bee rolling a ball, the observer bee subsequently used a more efficient ball than the one demonstrated. They are innovating, not just copying.
• Bumble bees have been introduced to New Zealand. In the 1890s, four species were brought from the UK to pollinate red clover. They established and have been there ever since. New Zealand has no native bumble bees.
• The "humble bee" name is older than "bumble bee." Darwin and his contemporaries consistently referred to "humble bees" in their writing — the name comes from the Middle English word for "humming" or "booming." "Bumble bee" won out by the early 20th century, and today "humble bee" reads as affected and archaic, but it was the standard scientific name for decades.
• Bumble bee colonies have a "thermoregulator" caste. When the nest needs to be cooled, certain workers fan their wings at the entrance, exactly like honey bees. When it needs to be warmed, workers cluster over the brood and shiver. The shivering can raise the local temperature in the nest by 10°C or more above ambient.
• Only one bumble bee species has ever been formally documented as going extinct in the wild in North America — Franklin's bumble bee (B. franklini) of Oregon/California, last seen in 2006 and presumed extinct. Several other species, including the rusty-patched bumble bee, are federally endangered.
• Bumble bees can't digest honey the same way honey bees can. They store small amounts of nectar in wax pots, but they don't concentrate it into true, long-keeping honey. The "bumble bee honey" stored in those wax pots is mostly thin, watery, and lasts only a few days — enough to feed the colony through a stretch of bad weather, not enough to carry it through a winter.
• The wings of a bumble bee beat roughly 200 times per second. The distinctive low, loud buzz you hear is at about 180–200 Hz — lower than the 230-Hz buzz of a honey bee. Bumble bees sound bigger than other bees because, acoustically, they are.

FAQ hooks (for LuperIQ / SEO)

• Is it a bumble bee or a carpenter bee?
• Should I remove a bumble bee nest?
• Are bumble bees endangered in Texas?
• Will a bumble bee sting me?
• How long does a bumble bee colony last?
• What plants attract bumble bees in Central Texas?
• Why are bumble bees important?
• Bumble bee vs. honey bee — what's the difference?

Sources consulted for this fact sheet include Texas Parks and Wildlife's Bumble Bee Conservation program, peer-reviewed research from the Chittka Lab at Queen Mary University of London (including Bridges et al. 2024 Nature paper on social learning), Leadbeater & Chittka work on social transmission, Howard et al. 2018 Science paper on the concept of zero in honey bees, and the US Fish and Wildlife Service species status reviews for B. pensylvanicus. Regional species distribution reflects Texas native-bee inventories.