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We’ve mostly focused on installing the orchard and vegetable gardens this year, but our gardens would only be marginally productive without some help from our resident pollinators.

 

Bombus melanopygus edwardsii (click any image to enlarge)

Some estimates suggest that bumble bees are believed to be responsible for the pollination of approximately 25% of crops in northern California.  Even after we add honeybees to the farm next spring, it will still be critical to encourage and support our native bee populations to help ensure that our gardens thrive year-round [1].

In early spring we were delighted to see hoards of native yellow-faced bumble bees (Bombus vosnesenskii) lurking in the lavender, and recently we sighted some native sweat bees on the Verbena and heirloom sunflowers in the gardens.

However, over the weekend we found this large and beautiful bumble bee lazily meandering around the Dotted Mint (Monarda lambada) in the herb garden, and thankfully she didn’t seem to mind the camera’s lens in the least.

 

Bombus melanopygus edwardsii approaches a Monarda lambada flower...

 

...in the hopes of finding some nectar

After some sleuthing, this female worker appears to be the edwardsii subspecies of Bombus melanopygus, also known as the Black-tip Bumble Bee [2,3].  She was a large bee, and not particularly fast moving.

Identifying her was a little challenging, but one distinguishing feature for this species is the black band running from side to side on the thorax, which is surrounded by yellow hairs.

 

Bombus melanopygus edwardsii has a black band, surrounded by yellow, on the thorax (ignore the pollen smudge running through the band)

The face of Bombus melanopygus edwardsii is light in coloration, similar to the yellow-faced bumble bee.

 

Bombus melanopygus edwardsii has a pale yellow face...

 

...very similar to the yellow-faced bumble bee (Bombus vosnesenskii) shown here

The abdomen is divided into 6 (female) or 7 (male) segments, called ‘terga’.  Tergites 2 and 3 provide important clues for identifying this subspecies, which are rufous red in the species B. melanopygus, but black in the subspecies B. melanopygus edwardsii.

 

The abdominal bands are black in this species

In addition to these black hairs, B. melanopygus edwardsii has thick yellow hairs on tergites 4 and 5, with a black tail tip.

 

As its common name suggests, B. melanopygus edwardsii has a black tail tip

Although the yellow-faced bumble bees seem to be the most prevalent here, we do occasionally see other species, but this is the first time we’ve been close enough with the camera to identify one of the other Bombus species lurking among our flowers.

 

Bombus melanopygus edwardsii

Bombus melanopygus edwardsii is native to western North America.  This subspecies reportedly nests both above ground, occasionally using old bird nests, and underground in small hollows and rodent burrows, and with an abundance of both on the property, we hope they find some suitable nesting habitat here.

 

Bombus melanopygus edwardsii

Honeybees usually come to mind as the most prevalent pollinators in most gardens, and as such many native pollinators are frequently overlooked. We’re now making an effort to pay closer attention to both the prevalence and diversity of our native pollinators here, and hope, through continued plantings of various native plant species over time, to encourage many more of our native bee species to visit our gardens.  I wonder who we’ll see next?

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[1] Native Bees are a Rich Natural Resource in Urban California Gardens (PDF)

[2] Guide to the Bombus of San Francisco (PDF)

[3] Discover Life Online Key to Bumble Bee Species