Researchers issue warning as harmful creatures spread across US territory: 'They can cause huge devastation'

The very hungry caterpillar plaguing Hawai'i isn't a beloved children's book protagonist — it's a voracious invasive species threatening the islands' economy and ecosystems.

What's happening?

Native to Southeast Asia, the ramie moth caterpillar is invasive in Hawai'i, and it appears to be spreading. The insects first showed up in the state in Maui in 2019 before moving to Hawai'i Island and Oahu. 

The Hawai'i Department of Land and Natural Resources noted that the caterpillar has also been detected in Kauai, Hawaii News Now reported. 

Why are ramie moth caterpillars concerning?

These invasive insects have huge appetites and can wipe out the leaves of native māmaki plants. In addition to being culturally significant to Native Hawaiians, māmaki forms an integral part of the local economy, as its leaves can be used to make tea.

Invasive species can damage ecosystems by outcompeting native species for resources, such as food and habitat. Ramie moth caterpillars also threaten the survival of Hawai'i's Kamehameha butterfly, which feeds on māmaki.

Ramie moth caterpillars are especially concerning because their populations can increase rapidly. Michelle Au, a graduate research assistant at the University of Hawai'i's College of Tropical Agriculture and Human Resilience, told Hawaii News Now that a single female can lay 100 to 200 eggs.

"They can cause huge devastation," she told the outlet.

What's being done about invasive species in Hawai'i?

Fortunately, birds have discovered that ramie moth caterpillars make a tasty treat, and their predation has prevented the insects from staging a full takeover on the islands, Au said.

Still, the state's Invasive Species Council encourages people to learn to identify the ramie moth caterpillar and report any sightings on the islands. It also suggests that people monitor their māmaki plants for extensive damage, which could indicate the presence of caterpillars.

Regardless of where you live, you can help stave off the threat of invasive species and strengthen your neighborhood's ecosystem by filling your lawn with native plants. 

Rewilding your yard can provide food and habitat for other native organisms, from pollinators to birds and reptiles.

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