Critically Imperiled Elfins Disappearing from the Forest

     

        

 Article and Photos by Bill Berthet Ixia Chapter

Frosted Elfin Panhandle area

Heart pounding, intoxicated with adrenaline, kneeling in a field of swaying 2-3 foot high wiregrass (Aristida stricta) I was trying to follow the fast, low erratic flight of a small brown butterfly. As it finally landed several feet off the ground on a curved section of wiregrass I was able to observe, photograph, and ID this butterfly as the frosted elfin (Callophrys irus Godart, 1824) Florida ssp. arsace (Boisduval & LeConte 1835) FNAI S1 (critically imperiled). I looked up into the clear blue sky with a fist pump yelling “YES!,Thank you mother nature for this moment!”. 

Dusky Roadside-Skipper 
nectaring on shiny blueberry 
(Vaccinum myrsinites)

Treasure hunting comes in many forms. A minute later I spotted two tiny dark butterflies whirling and darting around several feet off the ground finally landing, “Excellent” a pair of Dusky Roadside-Skippers (Amblyscirtes alternata) Florida Natural Areas Inventory S2 (imperiled).

Historically the frosted elfin has been documented from Ontario, Canada to Northern Florida (being the Southernmost extent of this butterflies range), from N. Carolina west to Wisconsin and Texas, for a total of 32 out of 50 states plus Washington D.C. and Ontario, Canada. The NatureServe classification is G3 (globally vulnerable)

Frosted Elfin larvae feeding on
Sundial Lupine 

The larvae feed on sundial lupine (Lupinus perennis) wild indigo (Baptisia tinctoria) blue false indigo (B. australis) and sometimes rattlebox (Crotalaria sagittalis). In Florida the larvae feed solely on L. perennis growing in 19 counties.

Historically this hairstreak had vouchered records from 17 counties in Florida. Recent records show this butterfly is only found in Clay, Franklin, Leon, Liberty, Nassau, and Okaloosa Counties at five localities. Locality records from Leon, Franklin, and Liberty Counties are within Apalachicola National Forest.

Frosted Elfin Nassau Co.

Frosted elfins, measuring a little over an inch, are hairstreaks in the Family Lycaenidae with hindwing tails, appear drab brown-grey with an olive iridescence, and are univoltine, having one brood of offspring per year. 

Sundial Lupine with Polyphemus cocoon 

In general adults are found near their larval host plants. They prefer shady areas where there is sundial lupine, yet this lupine is much more common in sunnier areas. Greater success in viewing adults is achieved on sunny days, minimal to no wind, and after 12:00 P.M. Males are territorial, often perching (sometimes moving its hindwings forward and backward in a wingsawing motion) on vegetation close to host-plant patches, and engage in vertical aerial combat flights. 

In Florida the adults fly during the months of February-April. In Nassau Co. I have observed adults nectaring on sundial lupine, shiny blueberry (Vaccinium myrsinites) and hawthorn (Crataegus sp.) but also use huckleberry (Gaylussacia sp.)

The fragile status of this butterfly in Florida can be found in frequently disturbed habitats such as oak-pine barrens, oak savannahs, upland pine or sandhill that share an open understory and a heterogeneous mix of open and closed canopy and edges that are managed by periodic fire (but not annual burns) where this butterflies larval host plant, sundial lupine (Lupinus perennis ssp.gracilis) is found. Non-woody plants would include wiregrass (A. stricta) gopherweed (Baptisia lanceolata) wooly pawpaw (Asimina incana) pinewoods milkweed (Asclepias humistrata) and shiny blueberry (V.myrsinites)

Open canopy Frosted Elfin habitat

Closed canopy Frosted Elfin habitat

Frosted Elfin eggs
on Sundial Lupine 

In Northern Florida the emergence of C. irus adults is strongly timed to coordinate with new host resources provided by its sole host plant L. perennis ssp. gracilis with a preference towards larger plants with increased depth of litter/duff around the plant, and the lack of feeding presence from other organisms.  One to seven eggs are laid on new leaf growth, on a joint between two leaflets, the growing flower stalk, or an opening on mature flowers. 

Larvae feed on leaves, stem, flowers, and early seed pods taking 4-6 weeks before pupating. Final instar larvae are usually found at the base of the plant and have a dorsal nectary organ that attract Ants of various species. Pupae are found in the leaf litter or soil near the base of the host plant. Some study has indicated that perhaps up to 25% of larvae pupate below the surface up to 1.20 inches in depth. This allows C. irus the possibility to survive seasonal burns that would kill other species.

Frosted Elfin larvae with ants 

Frosted Elfin eggs 

Sundial Lupine Seed Pod

Frosted Elfin Pupa 

Frosted elfins are thought to be extirpated from Ontario, Maine, Illinois, and Washington D.C., with populations declining through the rest of its range. Frosted’s are rated as S1 critically imperiled, or S2 imperiled in 20 of the 32 states it has been documented to inhabit. (table 1-2 Natureserve 2013)

Many factors are contributing to the decline of frosted elfins, including, habitat loss, direct mortality, land development, fire or disturbance suppression, local extinction of larval host plants, and browsing of flower heads by white-tailed deer.

Fire can have many positive effects on an ecosystem, including releasing nutrients that were previously locked up in inaccessible tissues in dead wood, litter, and duff, to live vegetation, animal matter and reduced fuel loads. Studies have shown that frosted elfin mortality from fire is significant. It is critical for land managers to understand fire tolerance for both the economically important and the rare, imperiled, or endangered species that need the habitat managed correctly. The timing and extent of prescribed fire is an important factor in the management of C. irus populations in sandhill pine and turkey oak forests. Some suggestions to improve fire as a habitat management tool for Frosted elfin habitat include designating portions of managed areas to be left unburned, better timing and extent of burn, using a longer fire return interval (not burning every year or two) the use of other types of management such as light grazing, mowing. or mechanical cutting.

The frosted elfin habitat in Nassau Co. is around 55 acres, and, I have observed the eggs, larvae, and adults from 2008-2013. After numerous trips during the years 2014 to 2016  I have not observed any adults, and have checked over 600 L. perennis host plants for eggs, larvae, or any kind of feeding activity , but none were observed. Too many prescribed burns over this 9 year period may have resulted in this critically endangered butterfly becoming extierpated from this site.

Comment from Matt Thom: It is such a challenge to try and find these butterflies, even when you know they should be there! I hope that it has been a matter of timing, that you missed the window for when they are active. Hopefully it isn’t because of the land management there. Could be just the ephemeral nature of butterfly populations; they can just disappear so fast with no real understanding of what caused it. If they are gone from this location, I’m glad I had the priviledge to study this population and document it’s particular unique characteristics.

References

Matthew D. Thom:  The Ecology and conservation of Callophrys irus Godart: The Role of Fire and Microhabitat 2013

Mathew D. Thom, Personal Communication

Dean K. Jue, Personal Communication

Atlas of Florida Plants Institute for Systematic Botany