I don't know about gulf frits in particular, but sometimes insects just go a little crazy and start laying eggs in random places. Last year, for example, I found a tiger moth laying eggs on the pavement in the middle of an apartment building. Nowhere near even a single plant. I also saw a moth whose name isn't coming to me laying eggs in a lone potted hibiscus in a back yard. When I looked up the moth, I saw that hibiscus isn't even in the family of any of their host plants.

I don't know why they do that (parasites? mutations? insecticide poisoning? damage from smacking into things?), but I raised the eggs of the first moth on the concrete. Many of them died for various reasons, but I think two or three managed to reach adulthood, so a) the eggs aren't necessarily infertile and b) the eggs themselves may not be damaged or poisoned.

Thanks, Radbat. I was wondering if I was the only one to see this.

I remembered this thread...this afternoon I watched 2 Gulf Fritillaty butterflies dancing around my fence. THEN I remembered that when I was cleaning off my fence, I found 2 volunteer passion vines. One is really growing well. Now I'm wondering if they were laying eggs? I looked on the orange tree today and saw 5 more GST eggs. I left them were they were. It was hard to do...
Kristi