Mating Valley Carpenter Bees

digger be mating?
Location: Superior, Az.
March 31, 2011 10:55 pm
Here is a photo I took today (March 31, 2011) in Superior, Az.
To me this looks like a digger bee mating with or riding around on a carpenter bee. They were connected the entire time they flew around the flowers in my yard.
Sexual dimorphism? What do you think?
Signature: T. Stone

Mating Valley Carpenter Bees

Dear T. Stone,
We are positively thrilled to receive your photograph that documents mating Valley Carpenter Bees,
Xylocopa varipuncta.  The species does exhibit pronounced sexual dimorphism.  The larger black female bee has a much longer lifespan because she must provision the nest with pollen and nectar.  The smaller golden male is quite territorial and aggressive, though he is incapable of stinging.  Females sting reluctantly.  Just yesterday, while working in the garden, we observed a male Valley Carpenter Bee defending his territory near the blossoming sweet peas.  The female Valley Carpenter Bees visit the sweet peas, stealing the nectar, an action described by BugGuide:  “Due to their large size, carpenter bees cannot enter tubelike blossoms such as sage, so they slit the base of corolla, a practice known as ‘stealing the nectar’ (without pollinating the flower). (UC, Davis)”  BugGuide also notes:  “Their eggs are the largest of all insect eggs. The Valley carpenter bee egg can be 15mm long. (UC, Davis)”

Update: April 2, 2011
Since Spring is in the air, we thought we would post this little excerpt from Daniel’s book, The Curious World of Bugs:  “One can’t help but be amused at the certain awkwardness that parents might encounter when using the proverbial bees to explain the facts of life to youngsters.  Most female honeybees are sterile workers that do not mate, the male drones are lazy freeloaders whose sole purpose is to fertilize the queen, and the queen loses her virginity to multiple partners in a short period of time in an insect orgy.  These are hardly the values that responsible parents would want to teach to their impressionable children.”
Ed. Note:  It should be noted that the above description is for the domestic Honey Bee.  Female Valley Carpenter Bees do not need to take multiple mates.  A single insemination is sufficient for her to produce her significantly smaller brood.

Question about Carpenter Bee nests
Male and female  valley carpenter bees
December 10, 2011 1:47 am
I live in highland park, CA.  And after very high winds here recently our tree in the backyard lost some large branches.  I started sawing the branches manually when I heard a distant buzzing sound and when I looked at the other end of the branch about a dozen male and female of these
bees had burrowed into this branch.  I’m wondering if their presence in the tree is killing the tree which helps us all breathe.   I dont want to harm them in any way. How can I gently have them depart the tree so that they may make their home elsewhere? Thank you kindly
Signature: Rey

Greetings Rey,
Our offices are in nearby Mt. Washington.  While we are not debating what you saw, we will challenge your interpretation of what you saw.  Valley Carpenter Bees are solitary bees.  After mating, the female excavates a tunnel in usually dead or dying wood, and then proceeds to construct a number of nursery chambers that each houses a solitary larva.  What you encountered is most likely a recently metamorphosed brood or broods that were uncovered when the tree was damaged.  These bees are not interested in returning to any nest, though a mated female may construct a new nest in the same tree.  Any Valley Carpenter Bee colony would have to be very extensive to kill a tree, however, weakened branches may snap in another wind storm if there is a significant amount of nest excavation.

Update:  March 16, 2014
We learned today that the Valley Carpenter Bee has the largest of all insect eggs that we know about.  According to BugGuide:  “18-26 mm (Largest bees in CA)  Their eggs are the largest of all insect eggs. The Valley carpenter bee egg can be 15mm long. (UC, Davis)”

Leave a Comment