Hi Gary. Yes, the butterfly females lay their eggs upon the host plants. Then, the caterpillars hatch and eat that certain plant until they are ready to pupate. Different species of butterflies use different host plants. So, if you include the host plantings along with great nectar feeding plants, the numbers of butterflies in your yard will increase. I am including a link from this site which will help you to know which plants the butterflies host on. And yes, it would makes sense to first educate yourself about which butterflies are in your area. BAMNA offers a regional checklist which you can use to narrow down to your county which butterflies have been reported in your area. As with most things, you can never say never, and a person might document a butterfly that has never been seen in their area before. I believe that Monarchs are the only butterflies that truly migrate each year. Hope that helps a bit. This is a great site for learning. Ask away. The great people here will help you with any question that you may have.
Angie

http://faq.gardenweb.com/faq/lists/butterfly/2004041551026161.html

http://www.butterfliesandmoths.org/checklists

I'm a total newbie, too,but there are some good books out there. One easy basic book is "The Butterfly Book" by Donald Stokes. It has lots of nice pictures and info about the most common species, plus info about best nectar plants and larval food plants. They may be the same or different. Good luck!
Liz

Butterflies do lay eggs on certain plants, and, usually, these plants are in the same family or order of plants, like question marks may use elms or nettles, both in the order Urticales. Gulf fritillaries use various passionvines, monarchs use various milkweeds, and pipevine swallowtails use various pipevines/Aristolochia. Some butterflies, like tiger swallowtails and variegated fritillaries, use a variety of plant families.

Some butterflies stay in the same area, while some, like monarchs and painted ladies, migrate. There is still a lot to be learned about this subject.

There is an FYI section on this forum that gives host plants for the various butterflies in North America. When this list was compiled, it only listed plants that members of this forum had actually witnessed being used, because there are butterfly host plant lists that list plants nobody on this forum has ever seen a butterfly use.

If you get into planting host and nectar plants, you'll really enjoy it! And you can ask all the questions you want to on this forum - we'll certainly help all we can!

Sherry

Not sure which zone you are referring to; it is unlikely to find a list of host plants per butterfly per hardiness zone, the zone used in the member headline of this forum. It is easy to find butterflies per state or county, a list of hostplants per butterfly, and then a region that plant grows.

Butterfly flight is quite purposeful, rather than random, because in a short lifespan they have to be fed and mate. It takes a significant storm to blow them out of their usual regions.

Plant lots and lots of Milkweed for the Monarch.
Painted Ladies and American Ladies are also found throughout North America and love thistles, Mallows, Everlasting and Pussytoes (Antennaria).
Black Swallowtails love Fennel, Dill and Parsley.
Zebra Swallowtails love Pawpaw trees.
Make sure to include a variety of native and naturalized (but not invasive) nectar plants to your region.
A tray of overripe bananas and mangoes will bring a host of butterflies that don't usually visit flowers.
A muddy, sunny spot in your garden will also be visited by "puddlers".
And most important, the use of pesticides is to be prohibited.
Bug and rodent/rabbit problems sooner or later attract a whole calvary of predators that come to clean house.