In spite of my best efforts, Gulf fritillary caterpillars have pretty well destroyed my native passion flower vines.
I apologize for posting this completely-unrelated-to-the-post link, but I thought you'd like it:
A gorgeous shot of a Common Kingfisher, from boston.com's "Big Picture" blog. ( http://www.boston.com/bigpicture/ ) Enjoy!
I have that same problem, Jim, and I don't want to dust the vine for fear of killing the honeybees that visit the remaining flowers. My passionflower vine also participates in shading the air conditioning unit on the back of my house, so I really rather resent it when the caterpillars destroy it. The vine recovers from the caterpillar onslaught each year, but looks terrible in the interim.
I would recommend using some other type of vine for shading or decoration. The Gulf Fritillary is abundant and widespread. I see individuals in Houston and in Atlanta. Passiflora is the host plant, so if you have Passifloras, you will have Gulf Frit. caterpillars. They are such a joy to see wafting by on their broad wings that I consider it a privilege to have any plant around that attracts them.Passifloras are not without defenses: they have nectaries that attract ants which provide defense in exchange for sugary sap. I have watched female Gulf Fritillaries in Houston lay their eggs on grass stems near Passifloras; it would appear this is a stratagem to give the eggs a chance to hatch without an ant attack. After hatching, the caterpillars move to the Passiflora.
Oooooooh, I love that photo! So beautiful!