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The Butterflies of Massachusetts

           43 Atlantis Fritillary    Speyeria atlantis  (W. H. Edwards, 1862)

Known in the 19^th century as the Mountain Silver-spot, the beautiful Atlantis Fritillary was locally common in western Massachusetts in the late 1980’s; today it appears to be in woeful decline.  Adapted to a northern climate and higher elevations, Atlantis is “trim and crisply marked” (Cech 2005), with a distinctive blue-gray eye.

Declines in both this species and Aphrodite Fritillary, and the extirpation of the Regal Fritillary, threaten to leave Massachusetts with only one fairly common larger fritillary, the Great Spangled Fritillary.

Photo: Mount Greylock, Mass. F. Model July 11, 2009

First described by W. H. Edwards in 1862, Atlantis Fritillary's original type locality was in the Catskill Mountains, at Hunter, Green Co., New York. (The type specimen and its label are in the Carnegie Museum; photos appear in Dunford 2005).

Thaddeus W. Harris had no specimens of Atlantis in his 1820-1850 Boston-area collection; only Aphrodite, Regal, and Great Spangled Fritillaries.  Prolific 19^th century collector F. H. Sprague did not find it in eastern Massachusetts in the late 1800’s.  By 1899 Scudder reports Massachusetts specimens only from the west:  Easthampton (Mt. Tom), South Hadley, Leverett and Deerfield (all F. H. Sprague), and Williamstown (S. H. Scudder) where it was “not uncommon” (Scudder 1899: 576).  At the turn of the century, then, Atlantis was known only in the Connecticut River valley and northern Berkshire County.  By 1917, it had also been found on Mt. Greylock and in New Lenox in Berkshire County (July 24 and 25, 1917, C. W. Johnson, specimens at Boston University). 

Interestingly, Atlantis may have ranged into northeastern Massachusetts in the 1920's, since it was reported from Lynn, Essex and Stoneham (Farquhar 1934). Collector C. V. Blackburn found it in Stoneham, but said it was "very rare" there, and A.H. Clark found it in a field in Essex on July 9, 1925. His two specimens preserved at Boston University do indeed appear to be Atlantis Fritillary. But overall in the state, Atlantis was uncommon throughout the twentieth century.

Regionally, high elevation is the key to this species’ distribution. A century ago, Scudder reported it “abundant” in the White Mountains of New Hampshire, and it is still easily found there today (see photos on MBC website).  In New York in the 1970’s, Shapiro (1974) reported it absent from “low, rolling country on the plateau,” but common in the Adirondacks and parts of the Catskills. Published maps (Cech 2005; Opler and Krizek 1984) show a disjunct between the eastern high-elevation New York/Pennsylvania populations and the western New York/Pennsylvania populations, and the comparatively isolated population in West Virginia.

Host Plants and Habitat

Atlantis Fritillary is characteristically a boreal species. Its preferred habitat is high-elevation cold stream and river valleys, where it utilizes both meadows and forest openings. It also uses northern bogs.  Scudder (1899: 376) reported that it preferred “sunny woodland nooks to open country.”

As with all fritillaries, the host plants are violets, although the precise species used in New England has not been determined. It may use several violet species. Shapiro (1974) reported it associated with V.  septentrionalis (Northern Blue Violet) in New York.  Scott (1986) mentions V. adunca (Sand-violet), V.   nephrophylla  (Northern Bog Violet), and V. canadensis (Canada or Tall White Violet). All these are found in Massachusetts, but septentrionalis is the most widespread (Sorrie and Somers 1999), and may be the most likely host here.

The Atlantis probably benefited from the clearing of land for pastures, haying and timbering in the 17^th and 18^th centuries (Table 1: 1600-1850), particularly at higher altitudes.  Fields that are mowed or grazed, but not plowed, provide fertile areas for the spread of violets of many species.  What has an adverse effect on violets, and therefore on fritillaries, is tillage – the plowing of land in order to grow crops.  Most species of violets are very slow to re-colonize disturbed areas, probably because they depend on ants for seed dispersal.

Violets are also among those species whose flowering time does not respond quickly to climate change, and whose abundance in our area may for that reason be declining (Willis et. al. 2008). 

Like other fritillaries, Atlantis needs some open areas for nectar sources.  A strong flier, it may travel quite far in search of nectar, but precise distances are unknown.

Relative Abundance and Trend Today

The 1986-90 Atlas found Atlantis Fritillary in only 20 out of 723 blocs, making it Uncommon (Table 5). The published account called it “locally common,” but this is misleading since it could refer to only one or two spots in western Massachusetts.  MBC sight records 2000-2007 rank Atlantis on the lower end of Uncommon, from a statewide perspective (Table 5).  It is less often seen than Aphrodite Fritillary, and is about on a par with Northern Pearly-Eye or Pepper-and-Salt Skipper in frequency of sightings.

Strong evidence of Atlantis Fritillary's drastic decline comes from an analysis of MBC data using list-length, rather than number of trip reports, as a proxy for effort (Breed et al. 2012). This study finds a statistically significant 82% decline in reports of Atlantis Fritillary 1992-2010.  Atlantis Fritillary and Aphrodite Fritillary (85% decline), are two of the three species with the greatest declines in detection probability over this period.

The same picture is shown by MBC 1992-2009 sightings adjusted by total trip reports through the 1990’s (Chart 43).  Since 2000 numbers seen per trip have been low but stable, and 2010, 2011, and 2012 continue the pattern.

 Chart 43: MBC Sightings per Total Trip Reports, 1992-2009

Additional statistics published in Massachusetts Butterflies season summaries also show that numbers seen per trip have declined in recent years:  91% in 2007, 91% in 2008, 70% in 2009, and 74% in 2010, compared to the average for prior years back to 1994 (Neilsen 2008, 2009, 2010, 2011).

The majority of reports of Atlantis Fritillary in the state come from the Central Berkshire and the Northern Berkshire NABA Counts. The results of these counts show the same sharp decline after 1999 as do the numbers for the state as a whole. Table 43 gives the raw numbers reported, and the numbers adjusted by party-hours of effort, from these two major Berkshire counts over the last 20 years.  The counts produced high numbers of Atlantis in many though not all years up to 1999, then show a fall-off since.  1994 was a particularly productive year in both areas.

Table 43: Atlantis Fritillary reported on Central and Northern Berkshire NABA Counts 1991-2011

* The Count was held, and the two other greater fritillaries were reported.

The Northern Berkshire count began in 1993, and includes Mt. Greylock. The Central Berkshire count has been held since 1986, and includes October Mountain State Forest.  The numbers of Atlantis seen in the 1980’s on the Central Berkshire count show that this species was also quite common in that area in those years: 1986 (60); 1987 (550); 1988 (70); and 1989 (366). (No Central Berkshire count data was reported for 1990. 1980’s data courtesy of G. Breed.)

State Distribution and Locations

While central Massachusetts is the stronghold for Aphrodite Fritillary, the northwestern part of the state is the stronghold for Atlantis (Map 43).  Atlantis was found in only 30 towns in MBC 1991-2009 records, compared to 93 for Aphrodite and 176 for Great Spangled Fritillary. (There are a total of 351 towns in the state.)  Map 43 shades all towns where there has been even one report of an Atlantis Fritillary.  Two new towns, not shown, were added in 2010, Monterey and New Marlborough, both in the southern Berkshires. 2011 and 2012 add no new towns.

 Map 43: MBC Sightings by Town, 1991-2009

NABA counts are well-distributed across the state, but by far the most Atlantis reports come from the Central and Northern Berkshire counts. The Southern Berkshire and Central Franklin Counts also frequently report Atlantis, but in fewer numbers. Atlantis is rare on the Northern Worcester and Blackstone Valley counts, and has never been reported from any counts further east.  And, the 1986-90 Atlas did not find any Atlantis east of the Connecticut River valley.

Atlantis is a strong flier, and strays can sometimes be found far from expected habitat.  Perhaps this is the explanation for those puzzling reports from Essex County in 1920’s, and for the few 1990’s reports in MBC records from the southeastern towns of  Milford (1, 1999), Holliston (1, 1998) and Charlton (1, 1997).   It should also be remembered that the potential for misidentification – confusion with Aphrodite or Great Spangled Fritillary-- is high.  However, in the cases of Ashburnham and Athol, both near the New Hampshire border in Worcester County, central Massachusetts, specimens were taken in the mid-1990’s, confirming the reports for these two towns.

Several towns and locations stand out as having been good areas, at least in the past, to see Atlantis Fritillary. The locations are October Mountain State Forest (Pittsfield/Washington), non-Count max. 143 on 7/12/1998, but 6 on 7/21/2010, T. Gagnon et al.; Cummington max 30 on 7/3/1999 T. Gagnon, recent numbers lower; Florida max 45 on 7/13/1994 D. Potter; Savoy max 100 on 7/13/1994, D. Potter; Monroe max 20 on 7/19/1998 D. Potter;  Mt. Greylock (New Ashford) recent non-Count max 24 on 7/4/2005 S. and R. Cloutier; and Windsor Moran WMA recent max 6 on 6/21/2002 M. Lynch and S. Carroll and Notchview TTOR max 8 on 7/10/2012.

COLLECTORS PLEASE NOTE:  Because of the evidence of decline in this species, collectors are requested not to collect specimens except as part of necessary scientific research under the auspices of an educational or scientific institution.

Broods and Flight Time

Atlantis Fritillaries are univoltine throughout their range. Their typical flight time in Massachusetts appears to be shorter than that of the Aphrodite and Great Spangled fritillaries, but MBC records may be missing the earliest part of the flight, since they are based heavily on the NABA counts.   According to MBC records, the flight in Massachusetts lasts from mid-June through mid-September (http://www.naba.org/chapters/nabambc/flight-dates-chart.asp). Their flight begins later and ends earlier than that of Great Spangled.  Like the Great Spangled and Aphrodite, Atlantis is most common during July.

In nine of the twenty years 1991-2010, the first Atlantis Fritillary was seen in the third week of June or earlier (6/22 or prior). These sightings are 6/16/2004 Mt. Greylock B. Benner; 6/17/2009 Peru B. Spencer; 6/18/2010 Cummington B. Spencer; 6/19/1998 Savoy D. Potter; 6/21/2002 Monroe/Savoy/Windsor M. Lynch and S. Carroll; 6/21/1996 Royalston D. Small; 6/21/1995 Peru D. Potter/ 6/22/2007 Cummington B. Spencer, and 6/22/1994 New Ashford T. Dodd.

Between 1993 and 2010, there are only three reports of Atlantis Fritillary flying into September. The three latest dates in MBC records are 9/20/1999 Milford R. Hildreth; 9/12/1994 Heath D. Potter; and 9/1/2009 Savoy T. Gagnon.

For this species, the flight dates reported by Scudder are applicable only to the White Mountains in New Hampshire and the Catskills in New York, and therefore comparisons with Massachusetts are not possible.

Outlook

Several recent authors expect that climate warming in the northeast will lead to a decline in Atlantis Fritillary (O’Donnell et al., Connecticut Atlas, p. 292; Leahy, MAS 1986-90 Massachusetts Atlas; Cech 2005, quoting R. Dirig for New York; Breed et al., 2012). In Connecticut, Atlantis is state-listed as a species of special concern, and ranked S1 or highly vulnerable by NatureServe (2011).  In this species, climate warming may cause withdrawal northward and movement to higher elevations. This and other species vulnerable to climate warming in Massachusetts are listed in Table 6. 

In the last twenty years, both Atlantis Fritillary and Aphrodite Fritillary have declined sharply in Massachusetts. The state has already lost one greater fritillary, the Regal Fritillary.  Atlantis Fritillary is therefore listed here as a Species of Conservation Concern.  It needs increased monitoring, further study, and perhaps legal protection.

As with the Great Spangled and Aphrodite fritillaries, habitat loss to resorts, golf courses, shopping malls, corporate headquarters and second homes could negatively affect Atlantis Fritillary.  As NatureServe (2011) points out, Speyeria fritillaries do not make use of violet populations in highly disturbed habitats, such as lawns and most city parks.  NatureServe advises that a viable “element occurrence” for any Speyeria fritillary will probably be at least 10 hectares, and that viable populations will need both wooded areas with violets and nearby open areas with adequate nectar sources. 

© Sharon Stichter 2011, 2012, 2013

page updated  3-3-2013

literature cited

Species of Conservation Concern

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