Valley Carpenter Bees: A Local Mass Die Off

Valley Carpenter Bees: A Local Mass Die Off

Over the course of the last few weeks, I have been dismayed to find more than a half dozen dead female Valley Carpenter Bees, Xylocopa varipuncta, in both the backyard and the front yard.  I don’t think the dog is responsible for their deaths because I also found one on the ground at K’s house across the street last week. Plus, the dog doesn’t hunt bees out front, nor have I ever seen him go after these, just honey bees.

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I like having Valley Carpenter bees around the yard.  We have a fuzzy male that guards his territory between the veggie garden and the micro orchard of fruit trees when there are flowers around, ready and waiting for a lady bee or two to show up.  He kind of paces, well buzzes, back and forth, scanning the flowers for the lovely black female bees.  They are great native pollinators, don’t make hives, and are very docile, rarely ever reported as stinging. The honey orange colored males can’t sting and with the shiny black females, “You would pretty much have to grab one in your hand to get them to sting you or try damaging their nest to provoke them into stinging,” according to one entomologist at  According to U. C. Davis, Department of Entomology, they are the teddy bears of the bee world. More information can be found in one of my favorite insect book, Insects of the Los Angeles Basin, by Charles L. Hogue. *

Valley carpenter male bee Teddy bear
A honey yellow colored male Valley Carpenter Bee, protecting his territory in the backyard

In all the years I have lived here, I have never found any of these bees dead before mid May, 2012, let alone a bunch of them.  Initially, when I found the first one, I wasn’t too concerned and figured she died of natural causes.  By the time I found the third in a week, I was guessing it was maybe mites that got to them in their nest.  A couple of days ago, I found one on the ground that wasn’t dead, but it was clear she was ill, barely crawling around. I picked her up and put her on some of the Lantana flowers.  She died within the hour.  Now the count is up to 7, and that is just to ones I found, so there is probably many more dead bees.  I think my daughter, B, was the first to realize what might actually be going on…”Maybe someone is killing them, mom.”  As an organic gardener, it didn’t even dawn on me that someone would want them dead!  But I bet B is right.

Carpenter bees like to drill holes into wood to make their nests, including man made structures like fence posts, eves, decks, or siding.  Their drilling is not normally enough to cause structural damage, but it can look unsightly.  My friend, C, at the end of the block has a cute old fashion mail box on a wooden post with a few of their nests chewed into it, but she doesn’t mind the bees or the holes, instead pointing them out to the kids on the block as the female bee comes and goes.

what made the hole in fence post it was made by bee
Photo from Flickr of Carpenter Bee Damage on wood. Can be found at by Toby Alter

Not everyone is like me, nor my friend, enjoying having these bees around.  I guess they do look kind of scary, being so large, and loudly buzzing as they fly by.  I have one neighbor that has pretty much ripped out every plant on his property, cemented in the majority of the backyard and at least half the front yard is his effort, according to him, “to get rid of the bees in his yard.”  I was shocked when he first told me this years ago. 

Although I don’t know if the dead bees are coming from his property, someone locally, upset about the bees drilling holes in wood on their property, might be spraying the bees or their nests with wasp killer or other insecticide.  It makes me sad. If you have any other ideas what else could be killing these docile teddy bear bees, I would like to know.

If carpenter bees are a problem, better solutions include:

  • Fill wood cracks and surfaces so they are less attractive.
  • Paint or stain bare surfaces and prevent weathering. That way the surfaces are not attacked by bees.
  • Any unoccupied holes can be stuffed with steel wool or caulk to reduce the likehood of reuse.
  • Wait until the bees have emerged before filling the tunnels.
  • Provide wood or other areas that are okay for the carpenter bees to nest in. We made Carpenter Bee houses!
Male Valley carpenter bee
The lonely male carpenter bee still hanging around

8 thoughts on “Valley Carpenter Bees: A Local Mass Die Off

  1. I came across this post while trying to see if maybe the bees moved slower during some sort of post food hibernation process. I have two dying at my mom’s house. They’ve lived in her porch railing for years and now they are definitely sick and have been barely moving for days. Her railing is pressure treated with chemicals. Could it be that they finally ingested enough of the chemicals to kill them?

  2. My question is. Are the Bee homes you made working at attracting bees? I find the size hole that my bees make are 3/8 ” . Let me know how your homes are working if you get time.

    1. An update on the bee houses…no tenants to date. We have moved the houses around to a few different places and currently they aren’t up hanging. However, they were lots of healthy valley carpenter bees around last year. I didn’t find any dead ones in the yard. I have yet to see any this year, but it is still early. But we do have lots of honey bee activity in the yard.

  3. Bee and let Bee. Folks that harm any critter out of ignorance and fear are damaged. I swatted one of these carpenter bees down last spring while building a small shed on a secluded side of my home and my dog ate it. Then i started thinking. Maybe i invaded his privacy. I have several azaelas and thirty two camelia bushes in my back yard that have been steadily declining in blooms. Inspired. I decided to check out the bees role in my environment. I was amazed at the carpenter bees ability to manage my yard. I am building a bee home for them now.

  4. After a major rain storm this month, we have had a male Carpenter bee in our back yard twice. The significance of this appearance is that we are located in the Rio Grande valley just north of Albuquerque. Haven’t seen a female.

  5. Interesting point about a tenting maybe causing it. I had not considered that. I haven’t seen a tent on any houses on the other blocks in the track in the last month, but that doesn’t mean there weren’t any.

    As far as Vikane and plants, I am thinking it would probably depend on how far the veggie plants are from the house. Ask the company that will be doing the fumigation; they are probably the most informed on the health risks with the chemicals they use and the effects on food producing plants. Or call cooperative extension. They might have a good answer for you. Generally Vikane fumes go up when the tent comes off, not horizontally. But plants can get damaged within a few feet of the house as the tent is removed, especially if the soil is bone dry. Some plants are more sensitive than others.

    Like you, we saw termite droppings for a quite while before finally deciding to fumigate. We put it off until January when most of the plants weren’t producing and a lot were dormant. The company we used said a few months wouldn’t make a huge difference in the amount of damage the termites did. The owner made sure the workmen were super careful of my garden. We made sure to water really deeply for a number of days before hand. The Clivia and mother in laws tounge plants were the only plants that suffered some damage, mainly because they were near the crawl space air vents in the foundation. The apple trees were right up against the garage, but on the outside of the tents, and they made it okay, but again, everything was dormant with no fruit.

  6. I have these around my house, though I have never seen the male. Wild looking! I wonder if anyone who uses RoundUp or “the usual” pesticides could be causing it, as the wind carries a lot of things. Was there a house tented in your area recently?

    Speaking of that…I am told I need to tent my house for termites. Does anyone know if there is any danger to vegetable gardens from the fumes? I find myself hesitating to have it done, even as I watch the pile of sawdust grow on my hard wood floor!

I would love to know what you think about this.

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