On Jul 23, 2:27 pm, La Puce wrote:
On 23 Jul, 14:17, "Cat(h)" wrote:

Could it simply be that they just die when they're finished doing what
the Great Spaghetti Monster* put them on the planet to do?
*or other deity of your choice

Interesting cult you've got going there. This conjured up an image of
Uncle Marvo's lawn as a Waco scenario where all the bees held hands
and prayed and then died ... Maybe I'll get that tin foil hat now ;o)

But seriously, could it be that, around this time of year, bumble bees
are done with breeding, forageing, etc. and simply come to the end of
their natural life?
I read in this that the forager bumblebee's lifespan is about 4 to 7
weeks (depending on whether you include the larval stages).

http://www.bio-bee.com/english/bombus/live.htm

Cat(h)