Wednesday, September 17, 2014

Bumblebee Poster

We have created a poster of Bumblebees of Thurston County, Washington.  Four of the best BBee photos of each species, two each male and female, that Nancy has taken over the past few years make up the poster.  This poster is very regionally biased and may not match bees seen in other areas. Folk in other regions are encouraged to do something similar.  It has been a mostly enjoyable effort putting the photos into a poster, and small compared to the time spent by Nancy in the field.

The poster is now a feature of our Bumblebees page, along with some other information.

Omitted are common names.  There are common names out there, but they can be confusing in a different way and we generally either adopt our own or abbreviate the scientific name, like "Vos" for Bombus vosnesenskii.  

Bumblebee i.d. is not always easy nor certain.  The only certainty is that the more one watches the more one sees.  
Here are some hints on telling gender.   
Males are different in appearance and habit in several ways.   
1) Pollen basket.  If the bumblebee has a blob of pollen on the hind leg, the bee is female.  Even if not laden with pollen, the female hind femur is wider.  The males may have pollen on his body, but it is haphazard.   
2) Flower habits.  Males spend much more time drinking nectar and less time gathering pollen -- only enough to feed themselves.  Some flowers may draw mostly male bees, because they only produce nectar, or mostly female because they mostly produce pollen.  Some flowers draw everyone.   
3) Timing.  Males show up at the end of a nest cycle, never in early spring.  First a few queens show up preparing the new nest, then the female workers, then the males and the new queens.   
4) Appearance.  Males have longer antenna and a longer body, an extra segment each.  They typically have more yellow, although it may be a little or a lot more depending on the species.   
5) Sting.  Only females can sting, (and they can sting more than once, the stinger is unbarbed).  If you are very confident, you can test gender by hand-collecting a male.  If you get stung it was not a male.

Nancy Partlow photo credit
 B. californicus (fervidus) female
Nancy Partlow photo credit
 Bombus californicus (fervidus) male

Nancy Partlow photo credit
 B. vosnesensikii male
Janet Partlow, photo credit
 B. vosnesenskii female

Now as we head into fall, field study slows hugely with most bumblebees closing camp and dying or (if new queens) headed to ground until spring.  Mid-September and we have seen a few fat new queen vos, laden with fluids and calories, and a few workers of a couple of tenacious fall species are still out there.  In the meantime, over the next few months we will sort through photos and observations and work on both this and other pages about our native pollinators.


Additional resources

Bumble Bees of North America,  Paul Williams et al, 2014

Bumblebees of the Western United States,  Jonathon Koch et al, 2012 (PDF available)

Xerces Society bumblebee i.d.
Xerces Society,

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