Char, that's for all butterflies. Some lay fewer eggs, some lay more. The largest butterfly in the world, the Queen Alexandria Birdwing, which is very endangered, was found to carry an average of 23 eggs, I believe. But the caterpillars host on a type of Pipevine that grows on the other side of the world, so I am assuming they have a certain amount of toxicity. But normally, insects lay hundreds of eggs because there are so many things acting against them.
Black Swallowtails normally lay a lot of eggs, but then again, most of the things they eat aren't toxic. Well, some of their native host plants are (like Water Hemlock), but the herbs we grow obviously aren't. I refer to them as herb-stuffed caterpillars. Birds tend to feed on them pretty hard.
I grow Rue since it can host both the Giant ST and the Black ST. I got my first eggs of the season today and they were Black ST eggs. Surprisingly, I could only find five eggs on about nine plants. That's really low. Usually, I would expect more like thirty eggs. At least. I'm lucky that my grocery store sells organic parsley and dill that I can feed the cats so I don't run out of food.
