I see wild bee colonies all the time in New Mexico and some built a colony in my apartment wall in Arizona. These bees are serious... in fact, they kill several people every year.

I see lots of articles on bee decline, often blaming pesticides, but they don't seem to have affected wild bees (from my informal survey anyway). These wild bees are very similar to honey bees... I doubt an untrained person could tell the difference. I wonder why the decline in one and not the other? It seems pesticides would affect them both. My guess it has to with genetics and/or cultural techniques. I see mites mentioned sometimes as suspect.