Invasive moth found in Michigan gets new name because of derogatory term

Moths were first discovered in Michigan in 1954

Spongy moth caterpillars have spiky hairs and a pattern of blue and red dots. You may find beads of frass (caterpillar droppings) under trees. (Michigan DNR)

An invasive moth species, whose population has been exploding in Michigan over the last couple of years, has a new name because its original name included a derogatory term.

The “Gypsy Moth” is now the “Spongy Moth,” the Entomological Society of America announced this week, the new common name for the Lymantria dispar moth.

The hairy, yellow-faced caterpillar with pairs of red and blue spots down its back was big news in 2021 when a population explosion in Michigan caused leaf loss in oaks and other trees in infested areas.

Spongy moth is now the approved common name in the ESA Common Names of Insects and Related Organisms List. The old name was removed from this list in July 2021 because it contained a derogatory term for Romani people. The move is part of the society’s Better Common Names Project.

“When an invasive species carries the name of a nation or culture, it’s easy to unintentionally associate that culture with the pest’s harmful effects,” said Joanne Foreman, invasive species communications coordinator with the Michigan Department of Natural Resources. “We anticipate additional common name changes for other invasive species to reduce these negative connotations.”

The name spongy moth — derived from the common name used in France and French-speaking Canada, “spongieuse” — refers to the moth’s egg mass, which has the color and texture of a sea sponge.

Related: 11 invasive species to watch out for in Michigan

Gypsy moths were first discovered in Michigan in 1954. By the 1980s and 1990s, large gypsy moth populations cycled through Michigan, defoliating up to a million acres in some years, said Scott Lint, DNR forest health specialist. (Learn more about gypsy moths here from MSU Extension)

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