Like honey bees, bumble bees are considered “eusocial” bees. This implies that, like honey bees, they live in a colony with a queen responsible for laying all the eggs and a cast of workers that forage for food, care for the young, and protect the colony from outside threats. Colonies of bumble bees do not last more than a year or two (i.e. perennial). Instead, colonies only lasted a year, with new queens being born each spring and generating more colonies in the fall. To ensure a high number of new queens and males are produced at the end of the season, a bumble bee colony’s primary purpose is to collect as much pollen and nectar as possible.
Habitat and Distribution
Although few lowland tropical species exist, bumblebees are more commonly associated with temperate regions and are typically found at higher altitudes and latitudes than the other bees. Some bumblebees, including B. alpinus and B. polaris, can survive in extremely cold regions, while others, like B. hyperboreus, which parasitizes its nest, may not be found there.
Insects classified as eusocial have never been found thus far north before. Solar radiation, including the internal mechanisms of “shivering” and radiative cooling from the abdomen, is proposed as a means by which bumblebees maintain an optimal body temperature, which could explain their existence in frigid environments (known as heterothermy). Bumblebees and other bees have the same physiology, but the bumblebee’s mechanisms appear more refined and have received more attention from researchers.
Their wing spans lengthen as a means of adjusting to the thinner air at higher altitudes. Although bumblebees can be found all over the world, they are not native to Australia (outside of the Tasmania region, where they have been introduced). They are only found in Africa in the northern Sahara region. Additionally, they were brought to New Zealand from Australia more than a century ago, and their efficient pollination is crucial to the success of many native plant species.
The size of the nest will vary from bumblebee species to species. At the same time, most colonies consist of 50–400 members, some as little as 20 and as large as 1700 have been recorded. These nests are much smaller than honeybee hives, which may house up to 50,000 bees. Several animals prefer to have their young in underground burrows because of the protection they provide from predators and the fact that they can avoid the direct sunshine that could cause them to overheat.
Other animals build their nests high above, in places like trees or tall grass. Compared to the honeybee’s neatly arranged hexagonal combs, the bumblebee’s nest is a jumble of haphazardly packed cells. Workers aid in disease prevention by removing larvae or dead bees from the nest and depositing them outside the nest entrance. Nests in temperate zones only last for one breeding season since the birds migrate south for the winter.