The Zestos Skipper

* Contributed by David L. Lysinger
The Butterflies of the West Indies and South Florida, Plate 26 Figure 11, by Smith, Miller and Miller, Oxford University Press
The Butterflies of the West Indies and South Florida, Plate 26 Figure 11, by Smith, Miller and Miller, Oxford University Press

Once upon a time, the Florida Keys were predominantly covered with tropical hardwood hammock–a plant association of broadleaf hardwood trees that is the northern extension of flora occurring on neighboring Caribbean islands, like Cuba and Hispaniola. This fascinating ecosystem is home to birds, trees and butterflies unique to South Florida and the Florida Keys. Sadly, only remnants of this once glorious forest remain today.

A rather plain looking but very special butterfly, the Zestos Skipper, Epargyreis zestos, was, until recently, one of the rarest denizens of this ever-vanishing tropical forest system. The Key West Botanical Garden (KWBG), located on Stock Island, very near Key West, is believed to have been one of, if not the last of, the strongholds for this butterfly in North America.

Florida Hammock Milkpea Galactia striata On Key Largo  Photo by David L Lysinger
Florida Hammock Milkpea
Galactia striata
On Key Largo
Photo by David L Lysinger

As hardwood hammock was gradually lost to development and anti-mosquito spraying increased, the Zestos began to lose ground. This butterfly was formerly found on the southern Florida mainland and on the upper Florida Keys, but there have been no recent reliable sightings from those areas. Sightings of the Zestos at the KWBG became rarer and more sporadic until it was not seen at all after January 2004. Most thoughtful observers consider it extirpated from South Florida at this point. Some butterfly caterpillars, and the Zestos Skipper’s caterpillars seems to be a perfect example, are tied directly to one host plant. The Zestos’ plant is a small seldom noticed understory vine in the Pea Family, Florida Hammock Milkpea, Galactia striata. Without this Milkpea for the voracious caterpillars of this butterfly to feed on, there is no Zestos Skipper. To support and maintain the Zestos Skipper’s survival at the KWBG, it would have been crucial to bolster the garden’s population of Florida Hammock Milkpea and to plant it in newer areas, as the garden has continued to expand. Without a concerted restoration effort with all the costs and complications of securing appropriate breeding stock, it may be too late for the Zestos on Stock Island. However, in its work towards becoming a major attraction in “paradise”… and who knows, perhaps someday a national treasure…, the KWBG may be able to fend off extirpations in the future, using the lessons of the Zestos Skipper.