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ESA Petition filed to protect the Florida intertidal firefly (Micronaspis floridana)

By Richard Joyce on 28. March 2023
Richard Joyce

The Xerces Society has submitted a petition for the listing of the Florida intertidal firefly (Micronaspis floridana) under the federal Endangered Species Act

The Florida intertidal firefly, also known by the common names mangrove firefly and fiddler crab firefly, is a habitat specialist found only in the mangroves and salt marshes of coastal Florida and the Bahamas. Belonging to a tropical branch of the firefly family tree, this species is the only member of its genus in the United States. Adult Florida intertidal fireflies have a distinctive appearance, with a mostly transparent head shield, large eyes, and wide pale borders on dark wing covers.  After nightfall, adults fly low over coastal vegetation and flash a greenish yellow light every 1.5 to 4 seconds.


Sites mapped on coastal Florida and the Bahamas
This tropical beetle is only found in the mangroves and salt marshes of coastal Florida and the Bahamas. 


The larvae, which evoke caterpillars wearing suits of armor,  glow in the dark while searching for snails to eat near the high tide line. Both adults and larvae are active year-round in southern Florida, with highest abundance in the spring.


Florida intertidal firefly larva crawling on some rocks
Important players in the coastal ecosystem, Florida intertidal fireflies roam the upper intertidal zone feeding on snails. (Photo: Ted MacRae, iNaturalist, CC BY-NC.)


The Florida intertidal firefly was assessed as Endangered by the IUCN Red List of Threatened Species, a non-regulatory designation distinct from the Federal ESA. Its threats include habitat loss and degradation due to coastal development, light pollution, pesticides, sea level rise, and introduced nematodes. While it occurs within some conservation lands, there are no species-specific measures being taken to protect it. ESA listing and designation of critical habitat will prevent the extinction of this unique firefly.


Micronaspis floridana firefly in petri dish
With its large round eyes and transparent pronotum (the widened plate covering the head and thorax in fireflies), the Florida intertidal firefly is a charming insect. (photo: Richard Joyce.)


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Richard joined Xerces as an endangered species conservation biologist in 2022. He coordinates many aspects of the Firefly Atlas project, collaborates with researchers, land managers, and community scientists, and compiles and creates tools and resources that drive firefly conservation efforts.

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