Friday, May 29, 2020

Bumblebees: Out of the Shadows

bumblebeeWhen it comes to pollination it seems that honey bees are give the spotlight, but they’re not the only bees that shine for their ability to pollinate.  Bumblebees have their own unique abilities that honey bees don’t. 

Bumblebees are long tongued bees with tongues 15mm – 20mm long and are capable of pollinating tuberous flowers with deep corollas such as cucumber, tomatoes, melons, squash, thistle, honeysuckle among many others. 

In contrast, honey bees are short tongued bees with tongues 5mm – 8mm long and pollinate flowers that are flatter and shallow such as, coneflowers, daisies, apples, cherries, raspberries, cranberries along with a variety of others.

Bumblebees, due to their size and the fact they flap their wings 500 times per second verses 200 times per second like other bees, are able to achieve what is called buzz pollination. Pollen is costly for the plant to produce in terms of energy, so the plant wants to be sure that the pollen produced is transported effectively in order for it to be able to reproduce. Plants that have evolved this strategy have poricidal anthers, which means that the pollen is packed tightly into the anther (the part of the plant that holds the pollen).

Most insects are unable to access this pollen; however, bumblebees are able to contract their flight muscles, which produces strong vibrations that they direct on to the anther using their legs and mouth parts, resulting in a bee-covering explosion of nutritious pollen grains from the tip of the anther. The bee will comb most of these pollen grains from her fur and into her pollen baskets on her hind legs, but a few lucky grains will be missed and will go on to fertilize one of the next flowers she visits. For some unknown reason honeybees are unable to do this. Blueberries, tomatoes, aubergines and kiwis are just some examples of the many plant species that require this form of pollination. 

These robust, fuzzy insects are covered in soft forked hairs called pile, giving them the ability to collect large amounts of pollen that ensures the pollination of the following flower they visit.  This furry looking coat also gives them the advantage when it comes to surviving in cold temperatures.  Bumblebees are typically found in temperate climates, and are often found at higher latitudes and altitudes than other bees. Some species range into very cold climates where other bees aren’t found.  One reason for their presence in cold places is that bumblebees can regulate their body temperature, via solar radiation, internal mechanisms of “shivering” and radiative cooling from the abdomen (called heterothermy) not to mention the insulative value of the setae alone.

Colony differences

If there is a disadvantage for bumblebees, it would be the small size of their colonies, verses those of the honey bee.  A group of bumblebees is called a colony. Colonies can contain between 50 and 500 individuals, according to the National Wildlife Federation. A dominant female called the queen rules the colony. The other bees serve her or gather food or care for developing larvae. During the late fall, the entire colony dies, except for the queen. She hibernates during the winter months.  After waking from hibernation, the queen finds food and looks for a good location for a nest. Once the nest is found, she lays her eggs and stores up food for herself and the babies.

The queen sits on the eggs for about two weeks to keep them warm. When the eggs hatch, the queen feeds pollen to the baby bees, called larvae. At two weeks old, the larvae spin cocoons around themselves and stay there until they develop into adult bees.

The queen only takes care of the first batch of babies.  The first batch grows into worker bees that will clean and guard the nest, find food and take care of the next batch of baby bees.  The queen is left to do nothing but lay and hatch new eggs.  Bees born in late summer are male bees, called drones, and future queen bees.  Both leave the nest as soon as they are mature.  The males form other nests mate with future queens and then die.  After mating, the future queen fattens themselves up and hibernate throughout the winter.  

Honey bee colonies consist of a single queen, hundreds of male drones and 20,000 to 80,000 female worker bees. Each honey bee colony also consists of developing eggs, larvae and pupae. The number of individuals within a honey bee colony depends largely upon seasonal changes. A colony could reach up to 80,000 individuals during the active season, when workers forage for food, store honey for winter and build combs. However, this population will decrease dramatically during colder seasons.

Honey bee colonies depend upon diversity of population for survival, as each caste of bee performs specific tasks. Thus, while queens are extremely powerful within their societies, they cannot establish new colonies without the help of drones and workers, who provide fertilization, food and wax to construct the hive. Queens are the only members of a colony able to lay fertilized eggs. An egg-laying queen is important in establishing a strong honey bee colony, and is capable of producing up to 2,000 eggs within a single day.   When Winter begins to set in, like every other creature on earth, honey bees have their own unique ways of coping with cold temperatures. One-way bees prepare for the winter is by gathering a winter reserve of honey.

Honeybees head to the hive when temperatures drop into the 50s. As the weather becomes cool, the honeybees gather in a central area of the hive forming a winter cluster.  A winter cluster is much like a huddle you see at a football game, except it lasts all winter.

Bees have one main job in the winter: to take care of the queen bee. This means they must keep her safe and warm. In order to do so, worker bees surround the queen and form a cluster with their bodies. The worker bees then flutter their wings and shiver. This constant motion and continuous use of energy is how the bees keep the inside temperature of the hive warm. In order to keep shivering, the bees must have enough honey. This is how they get their energy.  

Though the queen is always at the center of the cluster, worker bees rotate from the outside to the inside of the cluster, so no individual worker bee gets too cold. The temperature of the cluster ranges from 46 degrees at the exterior to 80 degrees at the interior. The colder the weather is outside, the more compact the cluster becomes. On warmer days, bees will leave the cluster briefly in order to eliminate body waste outside the hive.  In late winter/early spring when the temperatures warm to 45 – 50 degrees, the remaining worker bees begin to forage because their honey stores have been depleted and wait to care for the next generation of colony members. 

Both bumblebees and honey bees are known to be sociable and docile creatures while foraging for pollen and nectar, but if you disrupt their home colony the consequences can be costly and painful.  Just like most of us, both of these creatures will defend their home and family/colony to the death.  This especially applies to honey bees who bravely defend their hive, knowing that one sting will be the end of their lives.  Bumblebees can be more dangerous than honey bees, as they do not possess a barbed stinger and are able to sting multiple times and survive.  Honey bees have a barbed stinger and when they sting their entrails are removed and death is imminent. 

Bees are extremely important creatures to humans and animals alike by pollinating 90 percent of the world’s flowering plants.  It is imperative to our survival that we have a harmonious relationship with these little life keepers and lend a hand when they are in need.  

Related Stories

Jackie Woodcock was born and lives in the Adirondack Mountains. She is an apiarist, lepidopterist, conservationist, teacher, writer, artist, and a co-owner of SkyLyfeADK. You can find her SkyLyfeADK on Instagram and Facebook.

3 Responses

  1. Tom Vawter says:

    Aside from a few too many anthropomorphisms (e.g., queens ”ruling” the colony, workers ”knowing” that a sting will kill them) this is a nice article on important and interesting animals. Thanks.

  2. David Gibson says:

    Thanks so much Jackie for this great post on bumble and honey bees. We try to cultivate both. As for carpenter bees, which are in our structures, but also pollinators, I am brutal in netting and killing. Don’t wish to be, but I am.

  3. Ritaclare Streb says:

    Thank you. This is a wonderful comparison and much appreciated information. I enjoyed your descriptions and I believe that even these tiny creatures have a certain intelligence.

Wait! Before you go:

Catch up on all your Adirondack
news, delivered weekly to your inbox