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Rare Invertebrates

By Phillip deMaynadier and Beth Swartz
MDIF&W Wildlife Biologists, Bangor

The Wildlife Division of the Maine Department of Inland Fisheries & Wildlife is responsible for the conservation of the full diversity of Maine’s wildlife. Maine is home to 18 species of frogs, toads and salamanders (amphibians), 16 species of turtles and snakes (reptiles), and over 15,000 species of terrestrial and freshwater invertebrates, from beetles and butterflies to mayflies and mussels, to name just a few. Coordinating survey, research and conservation priorities for such a diverse suite of organisms is a challenge! One of the Division’s highest priorities is to address the protection and recovery needs of the large number of reptiles and invertebrates currently represented on the state’s official list of Endangered and Threatened species (21 of 45 species). Some state endangered invertebrates, such as the Katahdin Arctic Butterfly, are endemics – found nowhere else in the world but Maine.

Rare Dragonflies

Insects in the order Odonata, damselflies and dragonflies, are a significant and conspicuous component of Maine’s wildlife diversity. Presently, 158 species have been documented in the state, comprising nearly 36% of the total North American fauna. Several of Maine’s odonate species are of national and global conservation concern. In 1997, at MDIFW’s request, the Legislature designated the ringed boghaunter dragonfly (Williamsonia lintneri) as Endangered, and the pygmy snaketail dragonfly (Ophiogomphus howei) as Threatened. MDIFW currently lists an additional 25 odonates as species of Special Concern. While several odonates are highly sensitive to freshwater habitat degradation and experiencing declines nationwide, baseline information for the group has been lacking in Maine, until recently.

In 1998, MDIFW received a grant from the Outdoor Heritage Fund to initiate the Maine Damselfly and Dragonfly Survey (MDDS). MDDS is a multi-year, citizen scientist atlasing initiative designed to improve our knowledge of the distribution, status, and habitat relationships of damselflies and dragonflies statewide. In addition to engaging over 200 of Maine’s non-game wildlife constituents and raising public awareness of invertebrate conservation, the MDDS has helped the Department more accurately assess the status of rare, threatened, and endangered odonates. To our knowledge, the MDDS is among the first completely state-sponsored dragonfly atlasing projects of its kind in North America and has received considerable notoriety (see web site below). Having recently completed its sixth and final field season, the survey’s results have far exceeded expectations and are best summarized by the following:

  1. Public Outreach and Involvement:

    Volunteer participation statewide: >200
    Volunteers trained in MDDS seminars: 95
    Newsletter issues published (“Mainensis”): 4
    Major press articles covering the MDDS project: 5
    Web site hits (http://mdds.umf.maine.edu/~odonata/) >20,000
  2. Scientific Contributions:

    Total records submitted (% increase over 1999 baseline): 17,264 (229%)
    New Rare, Threatened, and Endangered species records: 297
    New state species records: 10
    New U.S. species records (Quebec Emerald & Canada Whiteface): 2
    Scientific publications completed or in progress: 5

With the volunteer atlasing component of the MDDS project coming to closure, MDIFW has recently contracted Paul M. Brunelle, an accomplished odonate expert and graphic design artist from Nova Scotia, to assist with authoring and designing the project’s capstone product: An Atlas and Conservation Assessment of Acadia’s Damselfly and Dragonfly Fauna. Populated largely with data contributed by MDDS volunteers, this atlas will serve as the first authoritative publication on the distribution and natural history of odonates from Maine and the Canadian Maritime Provinces. Funding for this work comes from Loon Conservation Plate, Chickadee Check-off funds, U.S. Fish and Wildlife Service, U.S. Environmental Protection Agency, and the Maine Outdoor Heritage Fund.

Rare Butterflies

Hessel’s Hairstreak, Clayton’s Copper, Purple Lesser Fritillary, and Crowberry Blue are just some of the state’s rarest butterflies that are both colorful in name and on the wing, if you are fortunate enough to see one. In an effort to improve our knowledge of the status and habitat preferences of these and other rare butterflies MDIFW is actively studying the group during statewide regional surveys. Attractive, conspicuous, and ecologically important, butterflies have garnered increasing attention from scientists and the general public. By documenting the distribution and status of the state’s butterfly fauna MDIFW hopes to improve its understanding of the group and prioritize conservation efforts towards those species most vulnerable to state extinction.

Further supporting this goal, MDIFW received a grant from the Outdoor Heritage Fund in 2002 to contract a professional lepidopterist, Dr. Reginald Webster from New Brunswick, to help assemble a comprehensive assessment of the state’s butterfly fauna. Drawing from published literature and specimen records located in museums and amateur collections throughout the Northeast, Reggie assembled the first baseline atlas and database of Maine’s butterfly fauna – an essential step toward conservation and management of the group by MDIFW and cooperators. The baseline atlas project compiled nearly 9,000 records and added 11 previously undocumented butterflies to the state list, which now stands at 115 species. Of special note is the relatively high proportion (~20%) of Maine butterflies and skippers that are extirpated (5 species) or state-listed as Endangered, Threatened, or Special Concern (18 species), a pattern consistent with global trends elsewhere for the group. Unfortunately, additional endangered and threatened butterfly listings are imminent as a result of the state’s recent assessment efforts. Contact MDIFW to receive an updated checklist of the butterflies of Maine (phillip.demaynadier@maine.gov) or visit http://www.maine.gov/ifw/wildlife/wildlife.htm to download a pdf copy of Maine’s first baseline butterfly atlas.

Finally, a statewide butterfly survey is currently on-going. Sponsored by MDIFW, in partnership with the University of Maine at Farmington (Dr. Ron Butler), Colby College (Dr. Herb Wilson), and Dr. Reginald Webster of New Brunswick, the Maine Butterfly Survey (MBS) is a 5-year, statewide, volunteer survey effort. Following in the tradition of previously successful state-sponsored wildlife atlasing projects, including most recently the Maine Damselfly and Dragonfly Survey, data generated from the MBS will come primarily from citizen scientists. The survey will help fill information gaps identified during the baseline assessment (above) on butterfly distribution, flight seasons, and habitat relationships for one of the state’s most popular insect groups. Training workshops for new MBS volunteers are currently being scheduled; check the MBS web site for further details or contact the volunteer coordinator, Dr. Herb Wilson, at whwilson@colby.edu (207-859-5739).

Funding for this work comes from Loon Conservation Plate, Chickadee Check-off funds, The Nature Conservancy, Maine Dept. of Conservation, the Maine State Museum, U.S. Fish and Wildlife Service, and the Maine Outdoor Heritage Fund.

Clayton’s Copper Butterfly

The Clayton’s copper (Lycaena dorcas claytoni) is a small, orange-brown butterfly known only from a handful of sites in Maine and western New Brunswick. In Maine, most of our occurrences are centered in a ten square mile area around Lee and Springfield in northeastern Penobscot County. Three sites in northern Piscataquis County and two in Aroostook County have also been documented. Only one site, Dwinal Pond flowage in Lee and Winn, is known to support a large population (thousands) of Clayton’s copper. This butterfly is believed to be an isolated subspecies of the more widely distributed Dorcas copper (Lycaena dorcas), which is found across much of northern and western North America.

Clayton’s copper is found only in association with its single larval host plant, the shrubby cinquefoil (Pentaphylloides floribunda). This uncommon shrub requires limestone soils and has a scattered distribution throughout Maine. Although not considered rare, it occurs in few stands large enough to support viable Clayton’s copper populations. In Maine, shrubby cinquefoil typically occurs along the edge of calcareous wetlands (i.e. rich in calcium carbonate or limestone), which are also uncommon in Maine. It can also be found in old fields, but these stands are typically short-lived as a result of forest succession. All of the currently known occurrences for Clayton’s copper are circumneutral fens and bogs, or streamside shrublands and meadows.

Clayton’s copper butterflies take one year to complete their life cycle. In late July and August, when shrubby cinquefoil is blooming, females lay their eggs singly on the underside of cinquefoil leaves. Leaves and eggs drop to the ground in autumn, and the eggs overwinter. The pale green larvae hatch in spring and crawl back up the plant to feed on its leaves. After the larvae molt and pupate in early summer, adult butterflies emerge during July and August to start the cycle over again. Throughout the flight period, Clayton’s copper remains local to its cinquefoil stands, where the abundant yellow flowers provide its primary nectar source.

Clayton’s copper is listed as “endangered” in Maine because of the extremely limited number, size, and distribution of its populations; the limited availability of its habitat, and its near-endemic status in Maine. Forest succession, impoundments, and dewatering of wetlands for irrigation are currently the most serious threats to this butterfly and its habitat. In addition, the longterm viability of such small, isolated populations is uncertain. In 2006, several grants were awarded MDIFW and the University of Maine to investigate two key questions about this rare butterfly. Beginning in 2007, Emily Knurek – a graduate student at UMO – developed and is implementing a survey protocol to estimate the size of Maine’s Clayton’s copper populations. Having a baseline population estimate is critical to assessing a species’ true status and recovery potential, as well as establishing management goals and monitoring population trends. Emily will also investigate the butterfly’s taxonomic status. While most lepidopterists accept the subspecific status of Clayton’s copper, others doubt its validity – especially since the taxonomic distinction between Clayton’s and Dorcas Copper has never been quantified. Only detailed morphological and genetic analyses will determine if Clayton's Copper is a true subspecies, thus confirming and further increasing its conservation significance in Maine.

Funding for this work comes from the U.S. Fish & Wildlife Service, State Wildlife Grant Program, Maine Chapter of The Nature Conservancy, American Philosophical Society, Maine Outdoor Heritage Fund (Maine’s conservation lottery ticket), Conservation Plate (“Loon Plate”) revenues, and “Chickadee Checkoff” contributions on the State income tax form. Thank you!

Roaring Brook Mayfly

In 1939, T.H. Frison climbed Mt. Katahdin and unknowingly made a discovery that would one day puzzle the experts. Frison, a well-known Illinois entomologist, was collecting mayflies and stoneflies as he and his family hiked to Chimney Pond on a late summer day. Several years later, one of those mayfly specimens would be described as a new species. Aptly named in memory of its collector, Epeorus frisoni went largely unnoticed for another half century. But in the early 1990s, MDIFW biologists began updating Maine’s Endangered Species List and, for the first time ever, were considering the status of invertebrates. Mayflies were a well-studied group of insects, yet here was a species that had never been found anywhere else in the world since its discovery on Mt. Katahdin in 1939. This long history of a single occurrence, despite extensive collections and surveys of mayflies throughout Maine and North America, ultimately led to Epeorus frisoni being listed as endangered in Maine in 1997.

Unofficially dubbed the “Roaring Brook mayfly”, this little insect remained a big mystery to MDIFW biologists now responsible for ensuring its conservation. Nothing was known about its life history, habitat requirements, or conservation needs. Its current status and distribution on Katahdin were also unknown, since no one had looked for it there since its original collection at “Roaring Brooks”. To complicate matters, the species’ taxonomic validity had come under question. Its similarity to a closely related species had led at least one mayfly expert to suggest that the original specimen might be just a variant form of a more common Epeorus species found in Maine.

Without additional taxonomic study and an assessment of the species’ current status at Roaring Brook, MDIFW could not even begin to understand or address the mayfly’s conservation needs. If the same animal could be collected again, a mayfly expert might be able to determine if the original species description was accurate. If Epeorus frisoni was not a valid species, it certainly did not belong on the State’s Endangered Species List. However, if it was a valid species, Frison’s namesake would endure as one of the rarest mayflies in the world.

Recently, with special permission from Baxter State Park, MDIFW surveyed Roaring Brook and two of its tributaries to collect specimens of the Epeorus species that occur there. With the expert help of Dr. Steven Burian, a mayfly taxonomist from Southern Connecticut State University, MDIFW was able to confirm that some of the specimens collected from the two tributaries of Roaring Brook matched the specimen collected by Frison in 1939. By comparing them to other species of Epeorus found in Maine, we were also able to confirm that Epeorus frisoni was indeed a distinct and valid species!

Since then, Dr. Burian has also located a specimen of E. frisoni in a recent collection from Vermont. While it now appears the Roaring Brook Mayfly is not endemic just to Katahdin or to Maine, its status as a “narrow endemic” (i.e., having an extremely limited distribution) is very rare, and E. frisoni is the only mayfly known to be endemic to New England. Its single occurrence in Maine also continues to support the species’ listing status as state-endangered – allowing MDIFW to confidently advance an investigation of the mayfly’s life history and conservation needs. The more we learn, the more effectively MDIFW can survey for new occurrences statewide and further investigate the species’ rarity.

In 2005-2006, MDIFW continued surveys for the Roaring Brook Mayfly as part of ongoing ecoregional surveys for rare species. While high-elevation, headwater streams are not a common habitat type in the targeted Eastern Lowlands and Aroostook Hills and Lowlands ecoregions, streams on several of the highest peaks were sampled. No Epeorus frisoni were found. In 2007, MDIFW began surveys in the Western and Central Mountains ecoregions – two areas of the state that hold the greatest promise of finding new occurrences of this rare mayfly.

Funding for this work comes from the Maine Outdoor Heritage Fund (Maine’s conservation lottery ticket), “Loon Plate” revenues, and “Chickadee Check-off” contributions on the State income tax form. Thank you!


Region A - Southwestern Maine
Region B - Central Maine - Photos from the field!
Region C - Downeast - Photos from the field!
Region D - Western Mountains - Photos from the field!
Region E - Moosehead Region - Photos from the field!
Region F - Penobscot Valley Region - Photos from the field!
Region G - Aroostook County - Photos from the field!