The Convict Caterpillar

One August, these unknown critters were thoroughly devouring every part of my spider lilies, actually leading to pure devastation. I have only two small established groupings. Did I know what they were?

Well, they weren’t worms; worms don’t have legs. So that leaves caterpillars or grubs. Grubs are usually rather plain, white, or dull-white, so these are probably caterpillars. They are definitely colorful: black with white bands with orange head and rear.

From a web search, these pests were identified as convict caterpillars, larvae of the Spanish Moth, Xanthopastis regnatrix. The Spanish moth adults have a furry black shoulder atop colorful rosy-pink forewings with orange & black splotches; a black body and gray underwings. Wings have scaly texture such as butterflies. It is a worker of the night and is attracted to gardens with white or light-colored flowers and perhaps those of fragrance. Lights in urban areas could present a problem for night shift moths. Populations of butterflies’ world species (17,500 species) are definitely outnumbered by moth’s world species (160,000 species). Moths do count!

It is common to find the Spanish moth in the southern states, especially Florida, and on to Texas, northward along the Atlantic Coast to New York, and inland as far north as Kentucky and Arkansas. 

The favorite foods of the Spanish moth larvae are Amaryllidaceae, Iridaceae, and Liliaceae. All of which were on-site, but the plant selected was the spider lily, Hymenocallis caroliniana. In general, moths are a diverse & important part of our ecosystem. They are pollinators as they drink the plant’s nectar. Although, some moths do not eat. They are food for birds, bats, frogs, etc. Some larvae (caterpillars) are food to various animals, even humans. Because of the importance of moths, they could be similar to “the canary in the coal mine” by giving a heads up to changes in our climate and ecosystem. Critters always go where the food supply is.

Source: Brenda Johnson-McCracken County Extension Master Gardener

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About krjack4

Extension Agent for Horticulture Serving home gardeners and Green Industry professionals, including commercial fruit & vegetable producers. Advisor to: Christian County Master Gardener Association; Downtown Hopkinsville Farmers Market.