As I was doing my fall cleanup in the garden, I was surprised to find an unexpected fall visitor: an early stage Black swallowtail caterpillar munching on an Italian flat parsley leaf.
I knew parsley, along with dill, are host plants for Black swallowtail butterflies. But I hadn’t seen any swallowtail caterpillars on my dill or parsley plants all year.
Until this week.
Which is odd timing for a caterpillar in our area. It’s mid-fall in southeast Michigan and most butterflies have left our area, migrating south to warmer areas.
We usually have a hard fall frost by now, but not this year.
Like many other places, our weather this fall has been warmer than normal. And I’ve had some extended growing season for plants like zinnias, parsley, lettuce, cosmos, and dill.
About Black Swallowtail Caterpillars
I learned the Black swallowtail caterpillar has five instars (stages) which last three to four weeks. From what I discovered, the caterpillar I found is in one of the early instars.
As the caterpillar gets older, it changes to a green color with black bands of yellow spots before it forms a chrysalis.
Given the larval (caterpillar) stage can take “…10 to 30 days depending on temperature and type of host plant” and we’ll have much colder temperatures the second week of November, I suspect the caterpillar won’t make it through the fall.
