There's a whole host of pollinators other than domestic honey bees. Hover flies. Solitary bees such as sweat bees. Any given day as a look out at my orchard I see a odd assortment of insects working the early blossoms. (A more predictable crew of honey bees, bumblebees et al show up a little later, once the apples start to bloom.) As Villandry points out, this rag-tag crew may not be as effecient as honey bees, but for centuries native plants have been pollenated by indiginous bees and other insects. My early flowering plants such as Nanking Cherries never fail to produce some fruit, so someone is doing their job. My point is that any insect activity is a good thing. This colony collapse syndrome is a serious thing and may, in fact, shine a light on our over-dependence on one specific mode of pollenization. I've tried year after year to get a mason bee colony established here, but it still hasn't hit critical mass and I may abandon the effort. Like I said, if you have any insect activity, you're probably going to get some fruit set. Don

Your description doesn't ring any bells at all, which makes me wonder if you have a newly introduced pest that the "ag cops" should know about. Each county has an Agricultural Commissioner's office, which is responsible for watching for introduced pest species (they're the ones that set out japanese beetle monitoring traps, etc). You might want to call your local office and report it. Their job also includes helping homeowners with this sort of id and appropriate control measures, in case it turns out to be something common. Here is a link that might be useful: Ag Commissioners office

I can't tell for certain what she might be by the image, but the description fits that of one of the solitary wasps, perhaps the Cicada Killer wasp judging by how large you say it is. There are several species of solitary wasps, and many of them dig holes in the ground for nests. She will defend her territory vigorously, and can sting. Can't help you with the beetle without a picture, or a very good description.

Jennie, if it is dappled shade like I have under our big old oaks, lots of plants will do fine. Although I don't usually plant with seed, you can grow aquilegia (columbine), tiarella (foam flower), digitalis (foxglove-biennial,won't bloom first year), sweet woodruff, hosta (easier to buy the plant actually), hellebore (I haven't seen bees around mine, but I would think any flower would attract them), dicentra (bleeding heart-goes dormant in heat of summer). Anemones will bloom in the fall here in northern VA, but I am not sure how easy it is to plant them by seed. If you put in a few shrubs and then sow the perennials, you should have a wonderful garden by next year. If you want, you can also plant understory trees like dogwoods, serviceberries (shrub-like), etc. Also, check out the native plants site I've linked. You'll have the most success with plants that are adapted to your area. I hope it takes you to the part shade/shade plants that I searched for. You can narrow the search even more if you want. If you live in northern VA, a resource is Green Spring Gardens. Beautiful gardens and lots of knowledgeable people to help! Good luck. Here is a link that might be useful: natives