A few days ago, I discovered that caterpillars were devouring my dill (Anethum gravelons L.) plant. I was thrilled. Not the normal reaction Iím sure, but then I am a Master Naturalist.
There were a total of 15 rather large yellow, green and black caterpillars on my plants.
A little research revealed that these beauties are the pupae of the Eastern Black Swallowtail, (Papilio polyxenes).
Most everyone knows the life cycle of the butterfly. The Eastern Black Swallowtail, which is a beautiful but common butterfly, will lay its pale yellow eggs on a plant in the Apiaceae (commonly known as the carrot, celery or parsley) family. The plants are chosen because the taste and smell discourage predators. In the case of the dill, the color of the plants also help camouflage the pupae. This particular caterpillar also has an interesting defense. When disturbed it will display an orange forked gland. This gland releases a stinky smell which helps protect them.
When the eggs first hatch, the larvae is black with a white saddle. The saddle contains uric acid which acts as an antioxidant to protect the larvae from toxins in their diet. In a mere seven to 10 days, the larvae will grow to 27,000 precent of its original size. It then finds a place to pupate (become a pupa/chrysalis). In another 10 days, the butterfly will emerge, and the cycle starts again. In the South, three generations of butterflies are common. The third generation will overwinter, which means the butterfly will remain in the chrysalis until the weather warms.
So, if you discover that your plants are infested with the caterpillars what should you do? You have several choices. You can sacrifice the plants and enjoy watching the process. If you do decide to sacrifice the plant, the chrysalis can be very hard to find. Nature is very good at protecting itself. Of course that is my choice, but what if you want the plant? To simply eliminate the larvae, just pick them off the plant. It is not necessary to use a pesticide.
Another option would be to move the pest to another unwanted host plant, either yours or someone who is willing to allow them to eat their plant. Another fun choice would be to move them indoors and raise them. You can make a simple enclosure using an old fish tank. Cover the top with a wire mesh, provide food for the hungry larvae, and add a few branches about the size of a pencil for the chrysalis to hang on. Sit back and enjoy your own nature show, until it is time to release the butterflies.
Do you think nature should be part of our everyday life, not just somewhere to go on the weekends? You are invited to attend our free, open-to-the-public, monthly program on the fourth Monday of the month at 7 pm at the First United Methodist Church, Waxahachie, TX. For more information on the Indian Trail Master Naturalist Chapter, contact the Texas A & M AgriLife Extension Service at 972-825-5175 or visit our website: http://txmn.org/indiantrail/.