Species Profile: Franklin's Bumble Bee

Hello again, welcome back to animals under threat. Today, we will be covering a species of bee that has come under threat from habitat loss and introduction of exotic diseases. Please give a warm welcome to Franklin's Bumble Bee (Bombus franklini).

Franklin’s bumble bee belongs to the genus Bombus which contains over 250 different species of bumble bee. This species of bumble bee can be distinguished by their solid black abdomen and yellow U-shaped on the thorax. Females have black hair on their faces while males have yellow hair on their face. Franklin's Bumble Bee has the most restricted range out of all the bee species and is only found in Southern Oregon to Northern California, USA (BOMBUS SANDERSONI FRANKLIN, 1913).

Female (above) and male (below) Franklin's Bumble Bee by SANDERSON.

As with most species of bees, the Franklin's Bumble Bee lives in large social colonies made up of one queen and her offspring. This species of bee prefers to nest in abandoned rodent burrows, on the ground or in a pile of rocks so long as there is room, shelter, food and resting available.

As this species of bee belongs to the Bombus genus, they have a unique genetic system where unfertilized (haploid) eggs become males that carry a single set of chromosomes while fertilized (diploid) eggs become females that carry two sets of chromosomes. This is called the haplodiploid sex determination system (Endangered and Threatened Wildlife and Plants, 2019). This can lead to inbreeding due to lack of genetic diversity in the colony.

Franklin's bumble bee in flower by Pete Schroeder.

Due to the commercial use of Franklin's Bumble Bee colonies in greenhouse for pollinating of crops as lead to an increase of exotic diseases/pathogens affecting the native population. Some of these diseases are tracheal mites (Locustacarus buchneri) and intestinal protozoa (Crithidia bombi, Nosema bombi) which can transfer to other bees by flowers that an infected bee has fed on or within the colony itself. Loss of habitat due to agricultural reason has also affect the population due to the removal of native flower species which the bees depend on (Kevan, 2008).

Next time, we will be covering a species of bird from the genus Calidris.


References
BOMBUS SANDERSONI FRANKLIN, 1913 SANDERSON BUMBLE BEE 2014.

Endangered and Threatened Wildlife and Plants; Endangered Species Status for Franklin's Bumble Bee (Bombus franklini)2019, , Federal Information & News Dispatch, Inc, Washington.

Kevan, P.G. 2008. Bombus franklini . The IUCN Red List of Threatened Species 2008: e.T135295A4070259.

Picture reference
BOMBUS SANDERSONI FRANKLIN, 1913 SANDERSON BUMBLE BEE 2014. (male and female bee)
https://www.iucnredlist.org/species/135295/4070259 (bee in flower)