While watching a black swallowtail butterfly fly with some difficulty (and experiencing the awesomeness of holding the butterfly), my family and I thought that the butterfly may have recently emerged from the chrysalis. When everyone else went inside, I ran to check the dill.
The black swallowtail caterpillar eats fennel, parsley, and, when the other two are absent, dill. Ours are the opposite. Somehow my mom's consistent dill-growing and not fennel- or parsley-growing have reared a flock of swallowtails that not only prefer dill, but refuse to eat parsley. So, they eat dill.
I don't know about you, but that's incentive enough for me to plant a few herbs.
After I found 7 caterpillars on a dill plant, we immediately set about making homes for the little guys.
(The above photo was taken by my sister. For online safety reasons, we'll forget names.)
Black swallowtail caterpillars need dill and a stick (for the chrysalis). All the extra stuff is to make it more at home. Notice the brown carpet and roomy green sofas, as well as the— what's that the equivalent of? Chandelier? Christmas tree?
As you can see, we're very excited.
You can do this with pretty much any butterfly. Here are a few:
For more host plants, go to http://melanys.tripod.com/Feb.htm/. Oh, and if you need more persuading...
If there's one downside, it's that the mortality rate isn't perfect, but you have to remember that caterpillars die before adulthood in the wild too. Birds eat them, small mammals eat them, and snakes eat them, and some of them just die. By taking them in, none are eaten, but you can't get rid of the ones that just die. Still, if you take good care of them, then before the wings are dry enough to fly, you will hold a butterfly.