I assume that you don't mean gypsy moths and tent caterpillar, lol.

1. Prunus serotina/wild black cherry - tiger swallowtails, red-spotted purples and MANY moths, including cecropias
2. Sassafras albidum/sassafras - Spicebush swallowtails, promethea moths, and tulip tree beauties
2. Ptelea trifoliata/hops tree - giant swallowtails and tiger swallowtails
3. Salix spp./willows - Viceroys, red-spotted purples, mourning cloaks, and many moths
4. Ulmus spp./elms - question marks, commas
5. Diospyros virginiana/persimmon - regal moths, luna moths and many more
6. Liquidambar styraciflua/sweetgum - regal moths, luna moths, and many more
7. Liriodendron tulipifera/tulip tree - tulip tree moth, sweetbay silkmoth, tiger swallowtails, and others

That's a good start!

Sherry

I've read that oak is a hostplant for for more lepidoptera species than anything else. But I would never plant an oak because I'm used to them eliminating their lower branches. If I cannot reach any leaves on a tree, the tree is of little use to me.

If you want a tree that will provide you eggs/cats, I recommend wafer ash/Ptelea trifoliata.

If you want food for a variety of moth cats, sweetgum is my favorite.

If you want food for all giant silk moths cats, the search I did some years back found that wild black cherry and staghorn sumac covered everybody.

The trees I have planted in my yard for pillars:
tulip tree
wafer ash
shagbark hickory
paper birch
wild black cherry
black willow
pawpaw
chokecherry
sweetgum
staghorn sumac

My sassafras is still in a pot.

To continue Sherry's very good list.......

8. Texas ash [supports Io, waved sphinx, others]

Avoid black willow as it can become invasive. Plant a weeping or globe willow instead.

I have ash, sweetgum, and box elder maple volunteers everywhere so black willow volunteers would just be joining the club. The black willow I have is the "Webb" variety which is supposed to top out at 20' to 25' tall. I did not want something which would get huge.

I appreciate this as well. I need to plant some more trees and was also wanting to gear them to cats. I couldn't figure out why I had so many tiger swallowtails in the yard, until I saw they used birch, so I assume this applies to my river birch as well??? I keep looking for cats now, but they are probably too high up anyway.

To build on the lists given (which were very good)...
As KC said, Oak is used by quite a few bugs. I checked out HOSTS and red oak has 287 records. However most oaks get over 60 feet tall. Too big for my yard. I am curious about trying dwarf chinkapin oak (Quercus prinoides). It is supposed to only get around 20 ft tall. It is the only oak that suckers and is supposed to form more of a thicket. In addition, the nuts are supposed to be tasty to both wildlife and people. Sounds like a wonder oak!
-Elisabeth

@rhizo-No, I am DEFINITELY NOT talking about those insects! LOL.

A few questions. A few people mentioned some birch species, but can anyone comment on which birches have the best resistance to bronze birch borer and birch leafminer?? I've heard that these insects can cause problems for these trees and this warrants concern.

Finally, this isn't really a question but I found this PDF file online. It lists quite a few different species and their host plants. I hope it helps out a few people.

Also, can anyone comment on Wafer Ash's resistance to emerald ash borer?? These insects are becoming all to common in my area and I'd like to know what the odds of my trees being attacked are.

http://cincinnatibirds.com/wildones/HOST%20PLANTS-MOTHS.pdf

Wafer ash is just the common name for Ptelea trifoliata, which is a hardy member of the Rutacea/citrus family - the emerald ash borers won't bother it. Giant swallowtails use members of the citrus family exclusively, and tiger swallowtails use it occasionally, at least Ptelea trifoliata, that one member of the family.
My wafer ash/P. trifoliatas never reach true tree size, stay bush size, so you might plant them with that in mind.
Sherry

Oaks and willows seem to be enjoyed by many insects. Willow supports Io and will feed big poplar sphinx, but also will draw tiger swallowtails, tentacled prominant and Viceroy to name a few. If the cats look like dried bird droppings, they will be Viceroy. If they look like fresh, wet bird poop, they will be young tigers.