Wednesday, April 4, 2018

Common Eastern Bumblebee

Eastern bumblebees (Bombus impatiens) are one of the most common of all the approximately 50 species of bumblebees that live in North America. The genus name Bombus comes from the Greek word bombos which translates into "a buzzing sound". It is easy to see how they earned this name, as anyone can attest who has been around these large bees, their wings make a loud humming sound that would be hard to mistake for any other species of insect.

Easily recognized by their furry black and yellow bodies, these large (up to 1 inch) bees are one of the first bees spotted in early spring. Because of their ability to withstand much colder temperature than other insects it isn't uncommon to see them on sunny days in the upper 40's or 50's. Many species of bumblebees cannot fly unless their flight muscles are at least 80 degrees. They have developed several adaptations allowing them to accomplish this even in colder weather. On bright spring days they will find a sunny spot to bask, much like a snake would do, soaking up the suns rays until they are warm. They can also disengage their flight muscles, giving them the ability to vibrate those muscles without flapping their wings. By doing this they can elevate the temperature of those muscles allowing them to fly.

Early spring brings out the young queens that bred late the previous autumn. They are looking for places to set up homestead and often use old rodent burrows or other existing holes in the ground. They may also use hollow stumps or logs or occasionally man-made structures. Once she has found a suitable site she will begin foraging for nectar and pollen and fill the burrow with provisions. Once she is satisfied there is plenty of food she will begin laying eggs on the food pile and use her warm body to incubate the eggs, much like a bird does her eggs. Once these eggs hatch she will feed, clean and care for them until they reach adulthood. All of her offspring will be sterile female workers that will spend their adult life caring for all additional offspring of the queen. At this point the queens only job is to lay eggs and grow the colony. In the fall the queen will lay eggs that develop into fertile females and males. Once they reach adulthood they will leave the colony searching for mates. Once mated, males will die and females will look for places to hide away from the cold winter weather. Typically they will hide under leaf litter on the ground or within logs or stumps. Once spring returns the newly emerged young queens will start the cycle all over again.

Bumblebees, unlike honey bees do not gather nectar and pollen for future storage. Because they create new colonies each year there is no need to store food, instead all food gathered by the workers is to feed themselves, the queen and the offspring of the queen. A large colony of bumblebees would be around 150 bees, although some overly productive colonies may have up to 1,000 individuals living in it.

Honey bees are easily the most popular of all the pollinators, and this is largely due to the agricultural industry promoting their value to crop pollination. While there is no denying they are hugely valuable for the pollinating service they provide, they are long lived and easily transported to various locations, they however come in second to the pollinating abilities of the Humble Bumble Bee.
Bumble bees are stronger, faster fliers and are capable of visiting more flowers per minute than the HB. Because of their tolerance of colder temperatures they are able to be active pollinating on days that may keep HB's grounded. Bumble bees also have longer tongues than HB which allows them to reach deep into the long throats of tubular flowers. BB's also have much larger pollen sacks than HB's which means they can carry more pollen from flower to flower in a much more efficient manner than their distant cousins.

Even though bumble bees are excellent pollinators and should be encouraged in our backyard gardens or agricultural areas, it is hard to convince those that are afraid or allergic to bees to do so. It is easy to understand why, allergic reactions are nothing to mess with and can be life threatening. Even if you aren't allergic, a sting from one of these bees is painful!! Unlike honey bees which can sting once before dying for their efforts, bumble bees can sting numerous times. They are known to follow a potential predator for long distances chasing the threat away from the hive. My husband found this out when he was in his teen years. While working around a small farm his parents owned they inadvertently disturbed a bumble bee hive and dozens of worker bees were chasing them and stinging them before they knew what was happening. My husband took a sting right between the eyes that swelled his eyes shut. A few years later while riding his motorcycle a bumble bee made it's way into his shirt and stung him 5 times before he could finally kill it by hitting himself in the chest in the general direction of where he could feel the bee moving around and drilling him with an oversized stinger inside his shirt. Needless to say he has a love/hate relationship with all bees.....mostly hate. While foraging on plants they are generally harmless and only sting if provoked. If you start swatting at them, it will most likely earn you a sting, and rightfully so. Their first instinct is going to be to protect themselves, and they will do this the only way they know how.

 Sometimes when I am working in the garden and I get too close to one of these busy little bees they will raise a leg at me, and while it looks like they are greeting me with a friendly wave. This little leg wave is actually a warning that I am too close and making them nervous. I move way giving them space and we all get along just fine.

Several years ago while visiting a local conservation area we noticed honey bees and bumble bees both visiting flowers.... looking for any nectar available so late in the season; which happened to be thistle blooms. The much smaller honey bees would fly toward the bumble bees and bounce off them with their legs and bite at them with their mandibles. They kept bombing the Bombus over and over trying to claim the flowers for their own. The bumble bees were no more bothered by their actions than we humans are when swatting at a pesky gnat. The bumble bees seemed to know they were large and in charge and couldn't care less that the honey bees were trying to bully them.

Prior to 1920 bumble bees were called humble bees and it is assumed they earned this name from the humming sound their wings make when buzzing around. After 1920 a few scientists who wrote articles in scientific magazines called them bumble bees and the name stuck. They have been called bumble bees ever since. I personally wish they were still called Humble Bees, especially given the fact that honey bees are getting all the love these days, and they are often overlooked. They humbly work in our gardens and agricultural fields often being passed over in favor of a non-native bee with better PR.