Now that it's the beginning of November, you can find quite a few Gulf fritillary caterpillars on the Maypop (Passiflora incarnata). Coincidentally or not, a couple of years ago in 2023, we photographed these critters on November 5th! How's that for consistency? This year, chilly, autumnal weather seems to be on the verge of freezing the Maypop vine, so hopefully the little caterpillars enjoy the green foliage while they can.
You can find the Gulf fritillary caterpillars on the prosperous Maypop vine, growing around the trunk of the deceased red cedar, near the Fitness Center. If you want to study the caterpillars, you will need to turn over some leaves―this one sits on top just for the photoshoot.
The other caterpillars were hidden under the leaves.
A couple of caterpillars were briefly relocated for a closer examination.
Examining the whole vine reveals the different sizes of caterpillars. As they grow, they molt, shedding their skin and becoming larger. These developmental periods between moltings are called instars (that's Latin for image, likeness, or kind).
The large caterpillar is more than an inch in length, while the tiny caterpillar is more than ¼ of an inch. That little fella is likely a newborn!
How long does it take the Gulf fritillary caterpillars to mature? The answer is about a month, with two or three weeks growing in the caterpillar stage and another week or two developing in the chrysalis.
Gulf fritillary butterflies (Agraulis vanillae) are abundant in the arboretum this month. How many Gulf fritillaries do you spy in this photo?
Here we see one fritillary sitting still and another one on the move.
The inside of the wings contains a gorgeous pattern reminiscent of stained-glass.
A second look at the crispy leaves reveals a fritillary!
This fritillary is in the weeds. We see some passionflower (Passiflora lutea). Do you know which vine is the passionflower? Passionflower is its larval food.
To see our previous posts on the beautiful Gulf fritillary:
Since we have been studying the caterpillar of the giant swallowtail (Papilio cresphontes), we might as well look at another interesting caterpillar, this time an arboretum favorite. The Gulf fritillary has appeared on the arboretum blog more than once (here and here). Summertime brings an abundance of yellow passionflower (Passiflora lutea) to the arboretum and every summer the fritillary comes back to enjoy it.
Here we see the Gulf fritillary eating a leaf of the yellow passionflower. Currently, this is the only species of passionflower in the arboretum collection. We ought to make it a priority to plant purple passionflower (Passiflora incarnata) in the spring.
We briefly removed the caterpillar from its vine so that we could take a measurement. At the moment, it's less than an inch long.
It's small, but looks scary! Aren't those spikes marvelous? Never fear; it's all for show. Presumably this is to dissuade any would-be predators. This type of defense color pattern is a different tactic than the one exhibited by the caterpillar of the giant swallowtail.
By contrast, the caterpillar of the giant swallowtail is inconspicuous: it both blends in with its environment and looks like something you want to avoid eating or even touching: a waste product.
If you stop to examine the passionflower vines (Passiflora spp.) at this point in the season, you may be lucky enough to spot a fritillary caterpillar. These little fellows look fearsome, but the spikes are all for show.
This caterpillar is happily munching away on Passiflora lutea.
Here we can see two caterpillars, separated by instar (the stage of development), age, and size. The tiny bloke hatched not very long ago, while the bigger specimen is close to metamorphosis.
How many caterpillars can you spot in this clump of passionflower vine?
