A Second Look Update--Bees

What are those bees doing?

I admit that as far as bees go, I have very limited knowledge. To me anything that buzzes and looks like it could sting is a bee. But as most of you know, not everything that looks like that is a bee. Some of them are wasps. And no matter how many times I try to learn the differences between the two, I don't remember for very long what they are. So here it goes again.

A papery, yellow jacket wasp's nest that I found
in the ground while I was weeding.
Yes, I did get stung.

Bees and wasps come from the same Order, Hymenoptera. After that, they differ in their Family, Genus, and Species. (Remember the taxonomy classifications for biology?) If you can get close enough to look at them, there are some physical differences. Bees are hairy and wasps are smooth. Bees usually have a fatter and rounder abdomen than wasps. And if the buzzing insect is chasing you, it's probably a wasp. Wasps are more aggressive than bees. Find a papery nest in the ground, it belongs to a wasp. Bees make waxy hives. All bees are social insects, but not all wasps are. Some are solitary. Bees eat nectar, but wasps usually eat other insects, unless of course you have a can of soda around. And the list goes on. There are over 20,000 different species of bees and over 100,000 different kinds of wasps, so if I'm playing the odds, wasp should be my first guess when I'm trying to identify one or the other.

Even though I refamiliarized myself with some basic bee and wasp knowledge, I was at a loss to explain what I saw about a month ago during a Second Look. I saw a smaller bee/wasp attach itself to the bottom of a different kind of bee/wasp. So it was time to go for help. The first place I turned was my bee expert--a friend who raises honey bees. I sent her pictures and asked her what was going on. She had no idea, so she sent them to her local county extension agent. The extension agent had no idea what was going on either so she sent them to an entomology professor she knew at large university. He didn't have a good answer, so he showed the pictures to all of his colleagues. And none of them could give a good explanation of what they saw. 

Smaller bee with larger ones to the side

Smaller bee attached to the bottom of larger bee

However, here is the information that they did provide for what they saw in the pictures above.

The responses I have gathered from my colleagues agree that this type of interaction with carpenter bees* is unusual. Bees sometimes get in territorial disputes, but this doesn't appear to be the case in the pic.  Everyone agrees that the bee on the carpenter bee is probably not doing any harm.  Based on what they could tell from the photo, and the host plant they are on, they believe the other bee is in the genus Osmia (e.g. blue orchard bee).  Why they are interacting like this is unclear. 

So I didn't get a definitive answer to my question, but I did learn a lot while looking for an answer. Now, lets see how long I can remember it. :)

*I called the big bees bumble bees in the original post, but they're not. They are carpenter bees as evidenced by their smooth abdomen. If they had been bumble bees, this area would have been hairy. Live and learn.

But Wait There's More:
--Did you know that male bees don't sting? The stinger is a modification of an ovipositer--an egg layer, so male bees have never had one to modify. This may be common knowledge for those of you in the know, but it was fascinating news to me.

--A good paint job is a good deterrent to the carpenter bees.


Sources:
http://www.diffen.com/difference/Bee_vs_Wasp

http://animals.pawnation.com/there-kind-bee-doesnt-sting-10377.html

http://www.everythingabout.net/articles/biology/animals/arthropods/insects/bees/

And some others that disappeared when my computer crashed. :(