These Buzzing Behemoths Are Peaceful Pollinators

Encountering a large bee in your garden can sometimes feel like a harrowing experience—the high speed flight of a stinging insect can make even the most grizzled soul turn tail. For the vast majority of situations, however, bees and wasps are not to be feared and, in fact, have very little interest in humans at all.

Bumble bees and carpenter bees are some of the largest bees native to North America and are commonly seen among a wide variety of landscapes. Although their size can sometimes make them intimidating, a closer look reveals their gentle nature and invaluable services to the ecosystems around them. These buzzing behemoths are incredible pollinators as well as food sources for a wide variety of birds and other predators. In general, the large size of these bees leads to them being more docile than other insects because their proportions keep most Earthly concerns at bay. Their hulking masses also help them fly in inclement weather that grounds other pollinators. This allows them to fill in gaps that might occur in pollination due to unfavorable conditions.

Bumble bees and carpenter bees also vibrate their flight muscles at specific frequencies while visiting flowers in search of pollen. Known as buzz pollination or sonication, this has been shown to help dislodge pollen in flowers with inverted bloom types such as blueberries, tomatoes, and similar blooms. These plants actually have more large fruit when pollinated through buzz pollination versus other types.

While bumble bee and carpenter bee females can sting, they only resort to such drastic measures when attacked or when their nest is directly threatened. These bees rely on their stinger to ward off predators such as birds and other insects. Unlike honey bees, they do not have barbed stingers and have the ability to sting multiple times without dying. Male bees cannot sting, as their reproductive organs are actually modified stingers. Carpenter bee males, which are easily identified by the large yellow dots on their foreheads, will readily challenge any creature entering their domain. They are all buzz and no sting, and a curious head butt is the worst offense to be expected by these charismatic creatures.

While bumble bees and carpenter bees share such interesting similarities, they are also very different in a few critical ways.

Bumbles and carpenters superficially look similar to one another, usually donning black and yellow warning colorations in their dense tufts of hairs. An easy way to normally tell the two apart is by looking at their butt. Carpenter bees almost always have shiny, hairless rears while bumble bees have more lush rumps. Interestingly, many bumble bee species are difficult to tell apart based on coloration alone because of the fact that the bumble bees in an area will eventually all begin to mimic the colors of the other bumbles around them. This is thought to have evolved in order to help predators more easily recognize their warning colorations, however it also makes casual identification difficult at best. There are over 20 species of bumble bees on the east coast, however only two main types of carpenter bees reside in the same area. Besides a shiny butt, the major difference between the two concerns their nesting habits. Bumble bees are primarily a social species, which means that they live together in small colonies centered around a single fertile queen. Most of these groups reach between around 30 to a few hundred individuals, and they are some of the only bees native to North America that are able to make true honey and beeswax. Bumble bee colonies do not store the huge quantities of honey that honey bees do. This is because the colony generally does not survive the winter and does not need a large cache of stores to survive the cold months. Instead, new bumble bee queens are born in the fall and mate with a handful of males before spending the winter sheltered in leaf piles or similarly protected areas while the original colony dies off. Leaving leaf piles on your property wherever possible is a great way to help the queens in your area have a nice winter.

Carpenter bees are mostly solitary bees that live in the branches of dead standing trees in a forest environment. Excavating galleries that can be several feet in length, they build individual rooms for their young using the sawdust from their excavations. Their tendency to bore holes into decks and houses is unfortunate, but in many cases they can be kept away by painting or staining any exposed wood. Even when they do make galleries in house wood, they construct their homes in the direction of the wood grain and do surprisingly little structural damage. In many cases, leaving dead standing trees and fallen limbs wherever possible gives these insects a place to settle down away from your constructions.

Many of our native bees are imperiled due to habitat loss, pesticide use, and climate change. As more natural spaces are transformed by humans, bumble bees and carpenter bees struggle to find areas to spend the winter and build their nests. These insects, along with many other pollinators, are also very vulnerable to pesticide exposure. Even things that might at first glance seem harmless—such as fungicides and herbicides—can be ingested by bees and combine with other pesticides encountered in the field to form more potent chemical cocktails. Even if a bee escapes such exposures alive, many times they suffer enough brain damage to hinder their foraging and nesting effectiveness. Also, as seasons become more volatile and unpredictable due to climate change, our native bees including carpenters and bumbles will face an uphill battle as they are forced to adapt. Recent studies have even found that the protein content of pollen seems to be declining as the amount of CO2 in the atmosphere increases. The lasting effects of such changes are impossible to truly predict, however by taking steps to foster populations of native bees in your area you can play a large part in ensuring their future.