Field Frame Friday: Caterpillars, Masters of Disguise!

Like many caterpillars in the family Papilionidae, spicebush swallowtails (Papilio troilus) are masters of deception. Young caterpillars mimic bird poop, while older caterpillars scare predators off with intimidating fake eyes (aka “eyespots”). During the day, they rest inside carefully constructed leaf rolls. The one you see above was made on one of its host-plants: sassafras (Sassafras albidum). Making these structures is a labor of love – leaf rolls take many layers of sticky silk and several hours to complete. Their leafy homes likely serve multiple purposes, perhaps protecting larvae from inclement weather, hungry birds, or roving parasitoids. They may even make eyespots more startling to any predators that peek inside!

[Photo and caption by Elizabeth Postema]

Hossie, T. J. & Sherratt, T. N. (2012). Eyespots interact with body colour to protect caterpillar-like prey from avian predators. Animal Behaviour, 84, 167–173.

Murakami, M. (1999). Effect of avian predation on survival of leaf-rolling. lepidopterous larvae. Population Ecology, 41, 135–138.

[Edited by Maggie Creamer]

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