A Guide to Identifying California’s Black Bumble Bee Species

As a longtime resident of California I’ve always been fascinated by the diversity of bumble bees buzzing around my garden. While the large fuzzy black and yellow bumble bees are familiar to most, California is actually home to several species of predominantly black bumble bees that are lesser known but just as important.

In this article, I’ll showcase some of California’s native black bumble bee species and provide tips on identifying them. As community scientists work to track bumble bee populations through efforts like the California Bumble Bee Atlas, being able to recognize these different bees is essential

Why Focus on Black Bumble Bees

There are over 1,600 species of bees native to California, yet some black bumble bees seem to fly under the radar compared to their more vibrant yellow counterparts. However, even less common bees play vital ecological roles. Understanding California’s native black bumble bee species enables us to support them.

Like most bees bumble bees act as essential pollinators of crops and wild plants. As bumble bees forage for nectar and pollen, they distribute pollen between flowers and ensure the plants can reproduce and bear fruit. Declining bumble bee numbers can put plants and the animals that depend on them at risk.

Several bumble bee species have declining populations in California, including the western bumble bee, Franklin’s bumble bee, and Crotch’s bumble bee. Protecting all bee species maintains biodiversity and healthy ecosystems.

Distinguishing Traits of Bumble Bees

Before identifying specific black bumble bee species, it helps to note some key traits of bumble bees in general:

• Large, hairy, round bodies with black, yellow, orange, red, and white color bands
• Short, stubby wings that produce a lower-pitched buzz compared to other bees
• Pollen baskets (corbicula) on hind legs to carry pollen back to the colony
• Nest in small cavities like abandoned rodent burrows, compost piles, under rocks, etc.
• Annual colonies initiated by a single queen; workers (females) and males live only through summer/fall

Common California Black Bumble Bee Species

Now, let’s explore some of the native black bumble bees you may see buzzing around California and how to identify them:

Black Tail Bumble Bee

The black tail bumble bee (Bombus melanopygus) is one of the most commonly seen black bumble bees in California. As its name indicates, it has a black abdomen but its thorax is covered in yellow hairs. Its wings are transparent with a slight yellow tint.

Nevada Bumble Bee

The Nevada bumble bee (Bombus nevadensis) has black hairs all over its body except for a patch of yellow on the front of its thorax. Its wings are clear with small black lines across them.

Hunt’s Bumble Bee

Hunt’s bumble bee (Bombus huntii) is primarily black but has some bright white hairs mingled on its thorax and the front of its abdomen. It has clear wings with distinct black venation.

Crater Lake Bumble Bee

The Crater Lake bumble bee (Bombus suckleyi) is mostly black but can be identified by the band of yellow hairs on the front half of its thorax. Its wings have yellowish venation at the base that transitions to black at the tips.

Western Bumble Bee

The western bumble bee (Bombus occidentalis) is solid black on its abdomen and thorax. Its wings have a slightly rose tint with distinct black venation throughout.

Locating Black Bumble Bee Nests

Keep an eye out for black bumble bee nests in these spots:

• Underground in abandoned rodent nests or under tufts of grass
• In old bird nests or cavities in trees, fallen logs, rocks, etc.
• Under man-made structures like sheds, porches, or window shutters
• In compost piles or piles of yard clippings

Supporting Black Bumble Bees in Your Garden

Here are some tips to make your garden or yard more welcoming to black bumble bees:

• Plant native wildflowers and flowering herbs they can forage on through spring, summer, and fall.
• Leave fallen leaves, brush piles, and unmowed areas to provide nesting habitat.
• Avoid pesticides that could be toxic to bees.
• Put out shallow dishes of water for drinking and maybe even mud for nest building.
• Build bee boxes or nests out of untreated, non-toxic wood.
• Report bumble bee sightings to programs like the California Bumble Bee Atlas to help conserve them.

Part of respecting nature is recognizing that even more obscure species have value. Familiarizing yourself with California’s native black bumble bees gives you a chance to learn from them and ensure these fascinating creatures—not just the brightly colored ones—continue thriving for generations.