Creature Feature: Rusty-patched Bumble Bee

In the garden, meadow, forest, apple orchard, and blueberry field, the bumble bees feed on nectar and collect pollen for the youth of their colony. In the process, they pollinate fruits and vegetables, giving more than they take.

For most people, the bumble bee does not instill the kind of fear as the honey bee, the yellowjacket, the wasp. Large and fuzzy, they are always seen and heard before they are felt, if they are felt at all. They only sting if pinched or threatened. And so they permit up-close observation. Most are striped black and yellow, some with a black smudge between the wings. Others have two orange stripes in the middle or toward the back end, or a belt of brown. But rare is the species with a specific bit of orange amid the yellow.

Last seen in Stockton Springs nearly a decade ago, the rusty patched bumble bee (Bombus affinis) is one of four bumble bees native to Maine that were once very common (the others being the American, the yellow-banded, and Ashton’s cuckoo bumble bee). Another 14 species live here, of some 46 in North America and 250 around the world.

Bees across the world have been on the decline, for reasons ranging from habitat loss to pollution to climate change. Honeybees get a lot of attention, although they are an immigrant species. The native rusty patched bumble bee ranges throughout the northeastern U.S., from North Dakota to Maine and south along the Applachian Mountains to Georgia. But the population has declined by more than 90 percent, prompting the federal government to officially list Bombus affinis as an endangered species in March 2017.

The rusty-patched prefers colder climates, as evidenced by its northerly and mountainous distribution. Drought or extended heat waves can wipe out a colony. But in terms of habitats and food sources, the rusty-patched is a generalist, living in a variety of landscapes including woods, marshes, farm fields, suburban parks, and gardens. This flexibility would seem to be a benefit, but it may instead be the source of the rusty-patched bumble bee’s downfall.