Sunday, August 7, 2016

To Each Her Own

Last week I had the pleasure of watching a female Gulf fritillary butterfly dance around the yard, looking for just the right place to lay her eggs. Gracefully she went from plant to plant, searching for the exact one that she needed. She landed many times, only to lift off again in just seconds when she realized it was the wrong one.

Gulf fritillary looking for nectar on Joe pye weed

Laying an egg (not much time to focus the camera!)
Finally, she found it. She found the passionvine (Passiflora lutea). That was the one she wanted. In a crazy, acrobatic move, she grabbed not a leaf, but a slender tendril (which is actually a modified leaf). She bent her body to it and laid a single, golden egg. Then she took another spin around the area, found another tendril, and laid another egg.

Left side: New egg  /  Right side: 2 days later

Passiflora lutea

How amazing is it that this small creature, just days out of her own chrysalis, knows just what to do? If she lays her eggs on any other plant, they will perish, unable to get any nourishment. Gulf fritillaries have evolved to eat only passionvine (Passiflora), just like monarch butterflies eat only milkweed (Asclepias).

There are several species of passionvine native to Georgia. The large purple one (P. incarnata) is probably the most familiar one. The one in my yard is much smaller, with a pale yellow flower. The vine is quite prolific, though, and it scrambles all over several shrubs. The fruits are small and dark blue, almost like an olive.

Since I saw where she laid the eggs (on my front porch, where the vine had sprawled), I was able to check on them with my hand lens. After a day, they started to darken, evidence of the growing caterpillar within. After 3 days, the first one hatched and climbed up the tendril to find a leaf. The tiny dark caterpillar was only visible because I was looking for it!

The first day it could only eat one side of the leaf, leaving a translucent hole like a tiny window. By the second day, it was making real holes but not big ones. Then another one hatched and crawled to its own leaf, bypassing the leaf occupied by the first one. How did it know to do that!

Two caterpillars, one still very tiny
I was nervous leaving them there. The plant was blooming and the flowers are apparently very popular with a medium-sized wasp. Wasps like to feed caterpillars to their young. I imagined these caterpillars falling prey to a wasp, so after a few days, I moved them to my caterpillar cage for protection. They were growing very well until I noticed that a few of them seemed to be dying. A friend said they might have a disease, so I removed them and cleaned the cage.

The remaining caterpillars are growing larger every day, occasionally pausing to transition to a new instar and shed their skin. Soon they will be attaching themselves to the upper part of the cage and developing a chrysalis in preparation for their final transformation.

Then the cycle will start again. In fact, these two were found in the garden several days ago, in the process of making more eggs.


  1. What a great photo of the golden egg being laid! So fascinating that you could follow its progress. The gulf fritillary is one of our favorites. We are amazed that the underside of the wing will look like a mirror, but in a photograph, you can see the "eye" and all the patterns!

  2. I am so proud of myself. I have a phobia about caterpillars. I go crazy if one gets on me. I had my husband cut down two catalapa trees when I found they get covered with worms that strip the leaves completely. My husband says I can see a worm a mile away and he can hear me a mile away when I see one. I say all of this to say this: I have a maypop vine. When I was little they grew everywhere and my daddy used to make little baskets or baby cradles out of them when the fruit was green. I found one growning in some sand on a creek bank and pulled it up. Didn 't think it would live, the root was so short. Put it in a pot and it covered the railing on my back porch. The blooms were so pretty and had a very nice smell. BUT one day a pretty golden orange butterfly kept flitting around it . And then little tiny spiked creatures appeared. OH my flesh crawled and I cringed having to use the steps. But I had read that the maypop was the only plant that the butterfly could use to lay her eggs and feed the larvae. So I am letting it stay. One of the worms has migrated to the porch and has made a cocoon. I am hoping that this will help me get over a fear that I have had since I was a kid. I think it started when I felt something on my neck and it was a tomato worm. And when I climbed to the top of a black walnut tree and grabbed a limb and felt something soft. I almost jumped out of the top of that tree. I really would like to overcome this fear.