Rusty Patched Bumblebee

Rusty Patched Bumblebees, or Bombus affinis, are a type of bumblebee. They used to be found from Ontario all the way south to Georgia and west to North Dakota, but since 2003 they have declined from 87% of their former range and are now mostly only found in Ontario. Even in Ontario they are facing extinction. Bumblebees, unlike other bees, are large, fuzzy, and carry pollen in baskets on their legs. Though female bumblebees can sting, they are pretty gentle and rarely do so unless forced to. They are, like most bumblebees, yellow and black, but their name comes from the males and worker’s rusty colored patch on the second segment of their abdomen. Rusty patched bumblebees perform a behavior called ‘nectar-robbing’, which is when they bite a hole on the outside of a flower and suck nectar with its tongue. This leaves a mark on the flower, which can help scientists know where these bumblebees live. Bumblebees in general grab the pollen producing structure and vibrate their wings, which dislodges pollen, in a process called ‘buzz pollination’. Rusty patched bumblebees live in colonies. In colonies there is one queen and many female workers. These bumblebees are between one and two centimeters long, and queens are on the larger end of this spectrum and workers at the smaller.

Recently, only a handful of specimens of rusty patched bumblebees have been found, and mostly in Ontario. Although the reason for their quick decline is not known, there are many suspected causes including pesticides, disease, habitat loss, habitat change, and possibly climate change. Pesticides often kill a lot of bees, and disease is spread from bumblebees that are used to pollinate plants in the commercial bumblebee industry. Habitat loss and habitat alteration is also a reason for their decline because it threatens their food supply. Agriculture and urban development threaten rusty patched bumblebees because it damages the flowers that produce their food and their nest sites. Livestock may also hurt habitat by removing food sources, altering vegetation and disturbing nest sites. The fragmentation of rusty patched bumblebees’ habitats diminishes populations, making inbreeding more common. Inbreeding leads to decreased genetic diversity. It’s not well documented or understood, but it is possible that parasites and climate change also adversely affect the rusty patched bumblebee. Because of all this, rusty patched bumblebees are listed as critically endangered on the IUCN red list.