Bumblebees produces a nest, rather than a true hive, but we will refer to them as hives for the sake of convenience. A honeybee hive in the wild can survive for many years, while a bumblebee hive is an annual event, with only young and freshly mated queens surviving through the winter in their native distribution. In New Zealand, the warm conditions mean that some bumblebee hives will often continue for longer periods, but the bumblebee queen stops laying eggs after the hive produces reproductive bumblebees (new gynes and males), and the existing hive is never revived by another queen. As the bumblebee hive does not overwinter, there is no need for the storage of large quantities of honey, so bumblebees do not produce quantities that can be commercially used by humans. Hives typically exist for 4-6 months from inception to completion (death of the queen and departure of new reproductive bees).
Bumblebees develop their hive from a single mated queen, unlike honeybees, who start new colonies with a swarm of worker bees and a queen. In spring, a young mated bumblebee queen emerges from an overwintering hole, where she has been hibernating. She will spend some time searching around for a suitable site to establish her new hive. In the wild this might be an abandoned rodent hole, or a dense low shrub. Once she has found the hive site, it she builds a small honey pot out of wax, which she exudes from between segments of her abdomen. She visits flowers to collects nectar to fill the honey pot, and collects pollen to make small balls (mixed with nectar) as a food store for her young.
The bumblebee queen then lays a group of fertilised eggs on the pollen balls, which she will brood over to keep warm, much like a bird would. The underside of the bumblebee queens thorax is hairless, which enables her to efficiently transmit body heat to the young bumblebee larvae. She maintains the hive’s heat at around 30˚C. During this time she still makes short trips outside to continue to collect pollen and nectar. Once the eggs have hatched the bumblebee larvae eat the pollen balls provided. Pollen is high in protein, which is necessary for the bumblebee larvae to grow and develop. After a period the larvae stop feeding and pupate. Approximately 2 weeks later, the adult worker bumblebee emerges.
After a few days workers take over the brooding and eventually the foraging duties from the queen, who focuses on laying more worker eggs. She will stay within the hive from now on. The hive continues to develop, and can vary in size from 80 to 400 bumblebee adults at its peak. Initial workers are small, but future adults generally increase in size as the bumblebee hive becomes stronger and more resources can be devoted to their development.
At some point the hive will start generating gynes (unmated queen bumblebees), who, after mating, will become the following year’s queens. The gynes, like the workers, are born from a fertilised egg. It is thought that the bumblebee queen prevents the early production of gynes by releasing a pheromone, which she subsequently stops. Gynes are feed more during the larval stage to assist their development and give them their increased size. At roughly the same time the queen and possibly some dominant workers will lay unfertilised eggs, which will develop into smaller males. Bumblebees have a haplodiploid sex-determination, simply put, the queens, gynes, and workers have 2 sets of chromosomes (from the egg and sperm), while the males have just a single set (egg only). This means that no male bumblebee has a father, or can ever have sons, but they do have a grandfather, and can have grandsons!
Male bumblebees do not collect pollen for the hive, and quickly leave to find a gyne to mate with. Gynes will also leave the hive to mate, but will return to build up fat reserves necessary to survive the winter. Finally, the young queens leave the hive to find suitable over-wintering holes, and the cycle begins again the coming spring.
Our rearing process closely matches the normal life-cycle of the bumblebee, however, by providing them with favourable environmental conditions and plenty of food, we are able to produce bumblebee hives on a year round basis. This enables us to provide bumblebee hives any week of the year, which is especially important to the glasshouse industry, and means the consumer gets great quality fruits and vegetables in the middle of winter! If you'd like to order a bumblebee hive, click here.