Bumblebee Basics: Nature’s Fuzziest Pollinators (with FAQs)

Bees are among the most recognizable, beloved, and sometimes maligned insects that people encounter in their everyday lives. Typically abundant in parks, gardens, and even densely developed areas, buzzing, busy bees are an important part of urban and agricultural ecosystems and a common outdoor acquaintance. Concerns over declining insects worldwide have recently brought bees more into the limelight, getting them much well-deserved attention. However, many people that I talk to express confusion about different types of bees, or even surprised that there are multiple kinds. In response to some reader requests from this past summer, we’ll be covering one particular group of bees in this month’s post: bumblebees.

Read More: Are Bees Endangered?

Bumblebees are a great choice for a Wildlife Spotlight post since they are found across much of the world, are familiar to lots of readers, and have a cool life history. Compared to the famous European honeybee, who we have to thank for most of our honey, bumblebees are unsung heroes of many temperate and mountain areas. So let’s get to know bumblebees, learn some cool bumblebee facts, and find the answers to common questions about them.

What are bumblebees?

Bumblebees are a group of about 250 bee species belonging to the genus Bombus. This scientific name is also the Latin word for hum or buzz, referring to the noise of their wings when they’re flying. Indeed, one of the first ways I catch on to the presence of bumblebees in any environment where I find them is their noisy buzzing. This also earned them the alternative name “humblebees” in English-speaking countries historically.

Read More: Genus? Species? A Beginner Naturalists’ Guide to Taxonomy

Compared to honeybees, bumblebees are often rounder, somewhat larger, and covered extremely fuzzy. Bumblebees’ fur, called pile, is a dense coat of little branched bug-hairs called setae. Just like mammal fur, this pile helps bumblebees stay warmer than many other insects, although it serves several other purposes too. Bumblebees’ pile fur coat also gives them their recognizable colors, which in many species are different bands of black, yellow, or white, typically in alternating patterns. These can also include rusty red or orange shades. This patterning is an example of aposematic coloration or warning colors, which helps other animals (including people!) tell them apart from other insects.

Read More: What is aposematic coloration?

Although they can vary tremendously in size within individual species (and within a nest!), most bumblebees are around a half of an inch to an inch long (12-25mm), with dark, clear wings that they fold along their bodies when at rest. Within a bumblebee nest, queens are typically the largest, with workers being smaller, and males similar to the workers or else slightly larger. They have black, fuzzy legs and short, black, hairless antennae. As I mentioned earlier, bumblebees have a loud, easily recognizable buzz when they’re flying, and tend not to spend much time perched unless they are resting on a flower or collecting nectar. These behaviors can help tell them apart from sneaky mimics that try to imitate bumblebees to avoid predators.

Bumblebee Life History

Unlike their more famous cousins the honeybees, bumblebees do not live in large or highly organized hives. Although bumblebees still work as a group, consisting of a female queen and her many daughters (workers) and some sons (males, or drones), they run a much smaller operation. While honeybee hives, which last through the Winter and persist through multiple years, can be home to up to 50,000 individual bees, bumblebee nests are more modest. Aside from young queens born in the Fall, other bumblebees don’t survive the Winter, so each nest starts from scratch from the efforts of a single queen every Spring. This keeps their numbers small: by the end of the summer, most bumblebee colonies max out at around 50-200 individuals.

Read More: Life Cycles and Life Histories – What are they?

What do bumblebees eat?

Like other bees, bumblebees get their nutrition primarily from flower nectar (for sugar and some micronutrients) and pollen (for protein). This is in contrast to their more ancient cousins, the wasps, who get their food by eating other animals. Bumblebee workers collect pollen from flowers, transport it in their corbiculae, or pollen baskets, which they sport on their legs, and store it in little buckets built into their nest. They use this stored pollen to feed growing larvae hatched from eggs laid by the queen. This is such an important part of bumblebee life history that you can tell some of the major lineages of bumblebees apart by how and where they store their pollen. Most workers rely primarily on nectar as their fuel, lapping it up with specialized tongues as they visit flowers.

Where are bumblebees found?

Bumblebees have an interesting distribution, being found widely throughout North and South America, Europe, and Asia, but having only a spotty distribution in North Africa. Strangely, they are totally absent in Australia, much of the rest of Oceania, South Asia, and the Middle East. The highest numbers of species of bumblebees are in mountainous and temperate regions where there is a greater variety of widespread flowering plants. Timing matters, too: in areas where lots of different plants flower in great number, but spread out across time, bumblebees presumably have an easier time being able to shift between available food resources.

Thanks to their fuzzy pile, bumblebees are better adapted to dealing with cold than most other insects. In combination with their ability to vibrate their wing muscles to build up body heat (much like when mammals like us shiver!), this equips them to be active in places that are too chilly for other bees. This means that bumblebees are a much more dominant presence in colder areas, or ones with cooler seasons during some of the year. In my own experience, I’ve seen the greatest numbers of bumblebees during my high mountain hikes in Montana and the Slovenian alps.

Can bumblebees sting?

The biggest bumblebee question I get from the general public is whether or not they can sting. I can remember friends telling me as a child that larger, fuzzier bumblebees were gentle and didn’t sting, while honeybees did so readily. While there is some truth to this, let’s answer this clearly: bumblebees can absolutely sting. As members of the order hymenoptera, female bees have a modified ovipositor (egg-laying organ) which functions for defense; what we call the stinger. Male bees, who don’t have female reproductive organs, don’t have stingers and can’t sting. Female bumblebees have stingers and are capable of stinging, but my childhood buddies weren’t entirely wrong: bumblebees are much less prone to stinging than wasps or honeybees, for instance.

Can bumblebees sting multiple times?

Ok, here’s a good one from the savvier folks. As you may know, honeybees can only typically sting once, since their barbed stinger gets stuck in the unlucky victim, and they do themselves substantial harm in trying to pull it back out. A worker honeybee is thus almost always fatally injured after stinging someone. By contrast, wasps, as I have experienced on multiple occasions, can sting a number of times without a problem. So the question is: can bumblebees also do this?

Yes, they can: female bumblebees’ stingers don’t have barbs, so they can if needed sting multiple times. However, as I mentioned before, they are much less prone to stinging than other insects. In my experience, bumblebees only sting when trapped or handled roughly. For instance, I once grabbed a female bumblebee off of a flower, mistaking her for a stingless male, and only after struggling between my fingers for a minute did she deploy her formidable stinger and make a jab at hand. Lucky for me, I was holding her at an odd angle and her attempt missed; I was so surprised I tossed her into the air and she flew off unharmed. The fact that she didn’t resort to this immediately tells me how comparatively gentle bumblebees are compared to wasps and honeybees, by whom I’ve been stung many times for even brief accidental contact.

Are bumblebees good pollinators?

As more people become concerned about pollinator declines I often get asked about how good a pollinator different bees, wasps, and butterflies are when I show them to people in the field. When it comes to bumblebees, I often tell people that they’re meeting a real pollinator all-star. Bumblebees are phenomenal pollinators for a couple reasons:

Buzz Pollination – Bumblebees use a behavior called “buzz pollination” to pick up loads of extra pollen from flowers that they visit. This involves vibrating their body and wings while inside the flower, dislodging loads of pollen onto their hairy bodies. Static electricity from their pile also helps draw in the pollen. When it comes to pollination, messier is often better (moving pollen from plant to plant), so buzz pollination can make bumblebees excellent at transferring pollen from one flower to another. Buzz pollination is especially important for plants like tomatoes, blueberries, and cucumbers, which have huge economic importance and rely heavily on bumblebees for pollination.

Activity in Poor Weather Conditions – thanks to their pile and their ability to warm themselves effectively by vibrating their wing muscles, bumblebees will be on the job when many other pollinators are staying home. When the weather gets cold or a little rainy, honeybees and other common pollinators will wait for better conditions, but honeybees are typically active. This means that they’ll be out earlier in the morning and later in the evening than many other insects. They really put the work in!

Gulo’s Picks: Recommended Books on Bumblebees

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