Invasion of the Gulf Fritillary Butterflies

Gulf Fritillary butterfly

Late each summer these bright orange visitors colonize the coastal Carolinas from the south. Gulf Fritillary butterflies are essentially a tropical species that cannot survive sustained freezing weather in the egg, caterpillar, pupa (cocoon) or adult butterfly form.  This means those that don't migrate south of the "hard freeze line" in Florida or along the Gulf Coast during winter are killed and the species is forced to recolonize areas to the north the following summer.  Southeastern North Carolina experiences at least a few hard freezes each winter that virtually guarantees no winter-surviving Gulf Fritillaries locally.

I have a large hedge of Lantana bushes in my backyard -- probably the primary reason I see butterflies at all as their bright yellow, orange and red flowers attract many species of butterflies to their limitless nectar supplies.  Lantana's not a North American native but is one of the best nectar-producing plants I'm aware of, feeding many butterfly species, bees, and even hummingbirds.  Gulf Fritillaries have always been attracted to the Lantana and I've observed them feeding ("nectaring" in butterfly-speak) here from early August up through the short, cool days of November.

This is the first year I've grown passionflower vines in my yard.  I've picked two species to try -- both of which are very cold hardy and should survive our North Carolina winters:  Maypop (Passiflora incarnata) and Blue Passionflower. (Passiflora caerulea)  These two species both serve as the larval (caterpillar) host plants for Gulf Fritillary butterflies and this means these creatures now have even more reasons to call my backyard home!

Three Gulf Fritillary eggs on
a Maypop leaf

Gulf Fritillary butterfly laying an egg
on the tendril of a Maypop
passionflower vine

It didn't take but a couple of days after first spotting the Gulf Fritillaries this year before I started seeing eggs on the leaves and tendrils of the Maypop passionflower vines.  These eggs hatched within just a couple of days into tiny black and orange caterpillars which immediately began munching away on the the leaves.  I actually ended up with more eggs than I knew the small plants could support, so I "thinned" them down to half a dozen or so. . .

Young Gulf Fritillary caterpillar

. . . but obviously I missed a lot of eggs because within a week I found nearly two dozen caterpillars ravaging the Passionflower vines!  I thinned these down to about half a dozen caterpillars, leaving just the largest ones.  These should be the first ones to spin cocoons that obscure the amazing metamorphosis process -- finally resulting in the caterpillars turning into adult butterflies.

Several caterpillars...

As of today the largest caterpillars are nearly 1.5 inches long and they're still ravenously eating.