National Moth Week 2023 - The Gopher Tortoise Shell Moth
There is life after death, indeed. The gopher tortoise shell moth (Ceratophaga vicinella) is a species of moth that feeds on the keratin-rich shells of deceased gopher tortoises (Gopherus polyphemus), a keystone species in Florida.
Tineid moths are one of the least flashy lepidopterans- comprising a large family of 3,000 species. Their drab appearance is eclipsed by their highly unusual dietary preference- fungus and detritus. Many Tineids feed on keratin, a fibrous protein forming the main structural constituent of hair, feathers, hoofs, claws, horns, and even fingernails. Extraction of nutrients from keratin is difficult and not a popular food source in the animal kingdom. The genus Ceratophaga within the Tineids are the only moths that specialize on hardened, dry keratin.
The gopher tortoise shell moth is a fascinating cause for conservation. This species is only known to thrive on dead gopher shells- fewer tortoises mean fewer of this species, too. What’s more, these moths need dead gopher tortoise shells that are found upside down. Larvae are cream colored with brownish heads and can be found on forming a group of burrowing tubes. The ecosystem in which dead gophers are found also matters- sandy substrates that allow these moths to build burrowing tubes deep into the sand that extend into the shell. These tubes help anchor the keratin shell in place. Burrowing between shell and sand mitigates predation as well as dehydration.
Caterpillars gregariously subsist on the tortoise skute until they are ready to pupate- en masse. Predation determent is further enhanced with pupae being lined with feces and sand. For most observers, the only apparent presence of this species is a decomposing tortoise shell covered with a clump of sandy pupae casings. Adult moths serve only to mate and do not eat.
This species is in decline as the habitat and population of gopher tortoises has declined precipitously over the past century. As unique decomposers, the gopher tortoise shell moth helps recycle nutrients back into the ecosystem. The life cycle of the Gopher tortoise moth was only described in 2005 by Mark Deyrup and his research team. The species is unique to all of the Americas, with the remainder of its genus found primarily in Africa.
Come celebrate moth awareness week collaboratively with National Moth Week and Florida Native Plant Society. Like and share your own experiences with us.
Caterpillar image courtesy of Brandon Woo and Carol Wolf
Adult image courtesy of Carol Wolf
Caption provided by FNPS President, Mark Kateli
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