Question
Hello Jim,

I am located in SE Massachusetts. We are in the midst of a
caterpillar invasion (forest, tent, gypsy you name em' we got
em')... but we have a tree on our property that seems to have
attracted lots more attention than just from the caterpillars.

The tree in question is a large oak, not sure which type, but I
could find out if necessary... doesn't have many leaves left. I
have noticed over the last week there were what looked like
white caterpillar egg masses on the trunk, but I suppose it could
be sap? There are a lot of wasps/bees (they have black bodies
with white striping on the end of the abdomen) that are
particularly interested in these masses. There are also some
butterflies that are attracted to this tree's bark (dark brown with
some blue and orange spotting... they are not moths) Today
(about a week into this observation) there were lots of carpenter
ants, and flies... Also noticed a hummingbird moth! There are
also very small flies (think they are flies) that congregate around
the masses.

The bark of the tree is darker about a foot off the ground to
about eight feet up the tree. There are small pieces of bark
missing... but the tree itself looks OK. There are a few dead
branches up in the canopy.... and as I mentioned before, the
moth caterpillars have really devestated the canopy.

What is attracting all these bugs? Sorry for the vague
descriptions, but there are so many wasps/bees at least 30
around the tree it is hard to get a close look at anything out
there. They appear to be fighting with each other over the
masses. I tried to find idnetification on them, but so far have
had no luck. The butterflies just seem to be sitting on the tree....
but there are usually at least 4-6 of them. The hummingbird
moths showed up today, and there were two of them.

Is this tree dying? Are the bee/wasps finding something they
want to eat??? What about all the other critters? It's definitely
weird! This in the only tree on our property with this much
activity.

Thank You!

Answer
I am not really sure about all this--some of the bee/wasp seem to be attacking the egg masses of the caterpillars. If only the leaves have been eaten then it is not likely the trre will die. Since this is complicated and should be looked at on the ground I recommend that you call the Mass. State Forestry Agency and ask one of their Foresters to come take a look. Here is their web link to their contact page. You can call the one closest OR call the Forest Health person at their headquarters  Charles M. Burnham,
Program Supervisor - Forest Health
http://www.mass.gov/dcr/stewardship/forestry/contact.htm