Jessica Morgan McAtee
Every fall, when we return to Florida from our Oregon summers, I am thrilled to see the first Zebra Longwing (Heliconius charithonia) butterfly. It brings back all of the nostalgia of my sunny childhood, peachy pink sunsets and humid November nights. And never gets old.
Unlike Oregon, and most other states, we can raise butterflies in south Florida 12 months out of the year. That means Zebra Longwings are year-round residents. They can have several broods throughout the year and in any month you may be lucky enough to find tiny yellow eggs on their host plant.
They lay those eggs, which remind me of tiny cobs of corn, exclusively on Passion Vines, but they are able to lay on many (not all) species of the plant. They do very well on our native Passiflora suberosa, which pops up in gardens like a weed and makes small black fruits which contain seeds. This species doesn't make a showy flower. However, they will also use several hybrids of Passiflora spp. with magnificent blooms, particularly ones with white and lavender flowers, not red ones. This Byron Beauty is one of many that I grow to raise them on.
When the caterpillars emerge from their eggs, they are tiny and yellow. Soon they appear white with black (harmless to humans) spines and this is how they look throughout all of their instars. They will eat all parts of the passion vine plant, leaves, stems and buds.
It is not uncommon for them to defoliate the plant like a hungry army. It can be stressful for a butterfly gardener to try to keep them all fed, similar to how it can be when raising Monarchs.
Once they get too big for their skin, they will molt. At first, the new spines are soft and clear, but once the new exoskeleton hardens, the spines will be stiff and black. You can see the discarded molt behind this caterpillar.
The last molt reveals a brown chrysalis with metallic markings and tiny spines. It looks like a dead leaf and is often found right on the passion vine that fed it. If you touch a chrysalis, it can wriggle around. This is a defense mechanism.
Zebra Longwing males can sense when an adult female is about to emerge from her chrysalis. Sometimes several males will compete for the same female. They will fly around her and land on the pupa. Eventually one male will pierce her chrysalis and mate with her before she even emerges. Pupal mating is not practiced by all kinds of butterflies, so it is interesting to observe the Zebras in action.
This neo-tropical insect can live up to nine months in its winged form, which is a long time for a butterfly. Like other butterflies, they will drink nectar from a variety of plants. Another unusual fact is that they will also collect pollen on their proboscis, in addition to their liquid nectar diet. It is believed that the protein in the pollen contributes to their extra-long life. If you look closely, you can sometimes see yellow pollen on their faces. This female emerged while connected to her partner and he obviously had a big meal just prior to hooking up.
One of their favorite nectar flowers is the firebush. With the simple combination of the correct passion vine and a firebush, you are likely to see this very popular Floridian in your Florida garden.
If you geek out on bugs, learn more about Florida butterflies from my gardening books.