Question about bees and their love affair with our shed

[Julie]

I hope this qualifies as a wildlife topic!

There are two smallish bumblebees guarding the entrance to our shed- black bums and fuzzy yellow/ no stripes at the front end. They're not aggressive but they are assertive and watchful, and it's now almost impossible to get into the shed without the smaller of the two flying right at me no matter how gently I approach. The instant I back off, it slips back in under the door and resumes marching back and forth just inside the entrance. Occasionally it looks as though it's scraping up the wood in a very wasp-like manner.

What is going on here? Are they nesting under the shed? (I heard some species like this kind of space, and the shed is wooden, elderly, and mounted on a solid interlocking paver foundation.) If they are, do I need to abandon the shed for the season? Kinda hard as it has all my gardening tools in it.

In no way do I want to spray Raid or do anything like that, but I cannot get into my shed without feeling pretty certain I'm going to risk a sting to the neck or face.

And while I'm throwing myself on your collective knowledge here, do an of you know where to find a good book or online source that will help us identify the many bees and wasp species frequenting our collection of native plants? Apparently our plantings have been very successful on the insect front because I've never seen such a range of flying creatures.

[BetCrooks]

If the bees are large, bumblebee size, they are probably Carpenter Bees. If so, they nest in the wood, specifically in a piece of wood where they can burrow in from the underside and then excavate their long tunnel to put the egg/s in.

Male Carpenter Bees do often defend a territory. They are trying to keep other Carpenter Bees away, not you specifically. They can be rather scary though, as they will hover at eye level inches away from you. My suspicion is that they see a reflection of themselves in our eyes.

Interestingly, male bees cannot sting. The stinger (which only females have) is a modification of the ovipositor. So the threatening male Carpenter Bees are harmless. Even the females are very rarely known to sting. (Honeybees, remember, are almost all females, except for the occasional drone. That's why we think all bees can sting.)

Personally I just swish at them irritably with my hat or hand and walk on by.

Now if they are smaller and have an oblong body, not a sort of round body, they might be wasps. Wasps can be nasty and sting hard and often. So I'd suggest looking up photos of carpenter bees before  you swat at them!

[Julie]

Thank you! I now have my shed back. Such smart people on this board...

Definitely carpenter bees now that I know what to look for. Is the smaller, pollen-laden one the female? I am only ever seeing two-- are there just two per excavation?

Funny that the male is so defensive about a large creature approaching the area, if he's more focused on other bees; even if he is not actually in the shed when I open the door, he immediately swoops in.

[BetCrooks]

If there aren't many suitable boards for nesting sites then you might only have one pair. If there are a lot gradually you will end up with quite a few bees. We had sun awnings supported on a series of 15 foot long cedar beams. We had to take down the whole structure because the number of bees got too high to be acceptable after a few years. The woodpeckers were also ripping the beams apart to get at the eggs and bees. But the untreated cedar with the thick vertical surfaces were ideal for them. Hopefully your shed has fewer opportunities.