Bombus pensylvanicus




The reproductive cycle of Bombus pensylvanicus is the same as other species of bumblebee.  Bumblebees produce my means of haplodiploidy, which means the female bees can produce eggs without mating.  Fertilized eggs can become either queen bees or female workers, and unfertilized eggs become males (Discover Life 2013).  dfg

The cycle begins at the end of summer when a newly hatched queen bee mates with a male.  The fertilized queen bee then enters hibernation until spring of the following year.  Once conditions are right the queen arises and begins a search for a nest, usually in March (Tranji 1996).  The Queen bee begins her colony after the nest is found and she has gathered nectar and pollen, which is used to build the wax pot and a source of nutrition; the pollen stimulates the ovaries to produce eggs; these eggs are fertilized from the previous year and will develop into female workers. The Queen keeps the eggs warm through the beginning stages of development with the use of her pubescence. The eggs then begin their life cycle beginning with the larval stage, pupae, and finally adult female workers, who tend to the nest, as well as the eggs the Queen continues to lay. It is approximately four to five weeks from egg to adult bee (Bumblebee 2013).  The first workers to emerge are small in comparison to those that will hatch and begin their life cycle towards the middle of summer.  These workers forage and contribute to the increase in size of the colony by providing resources for growth (Tranji 1996).  By late summer there can be over 200 worker bees.  By this time the queen bee has stopped producing a chemical, that has been produced throughout the life of the colony, which inhibits the ovarian production of the female workers and causes the Queen to lay worker females instead of queens.  When this chemical ceases, the Queen bee lays a batch of eggs that will themselves become queen bees; she also begins to produce male eggs.  This stage marks a change in the dynamic of the nest.  Some female workers are now able to lay their own eggs and do so despite the Queen’s attempts to destroy them.  The animosity and tension continue through late summer until finally the workers revolt and sting the queen bee to death.  The workers will not survive winter, but the batch of queen bee eggs the Queen herself laid have hatched, pupated, and left the nest to mate, hibernate through the winter, and begin the cycle again (BBC 2013).

The following link will take you to a video that shows yearly reproductive cycle of a bumble bee: