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The Butterflies of Massachusetts
46 Harris’ Checkerspot Chlosyne harrisii (Scudder, 1864)
History Host Plants and Habitat Relative Abundance Today State Distribution and Locations Broods/Flight Time Outlook
Samuel Scudder named this small bright butterfly in honor of Thaddeus W. Harris, who died in 1856. The species was known to Harris from one puzzling specimen from Sutton, in central Massachusetts. Scudder conclusively defined it as a new species.
By 1889 Scudder knew of records from only five Massachusetts locations (West Roxbury, Malden, Sutton, Princeton, and Springfield), a fact which suggests that Harris’ was not common. Scudder describes it as more common north of this state and at higher elevations, and belonging “more strictly to the Canadian than the Alleghenian fauna;” and not known south of Massachusetts (1889: 680).
Today, Massachusetts appears to be again the southern limit of Harris' Checkerspot, and the species may be withdrawing northward due to climate change. This species has not been found at all in Connecticut since the end of the 1995-99 Connecticut Butterfly Atlas; it is now listed as "Threatened" there. If Harris' Checkerspot is indeed gone from Connecticut, Massachusetts is the new southern limit. And, recent searches in southeastern Massachusetts have failed to find Harris' Checkerspot, although it was there in 1988.
Photo: Newbury, Mass. Martin Burns WMA, T. Whelan, June 19, 2006
Early museum specimens from Massachusetts are not plentiful. In the Harvard Museum of Comparative Zoology (MCZ) there are six specimens from Malden dated June 23, 1883, and one from Wollaston June 19, 1878, all by veteran collector F. H. Sprague. There is also a surprising specimen from Mt Tom, collected by Scudder and dated 1831, which is not mentioned in Scudder’s writings. At Boston University (BU) there is a June 14, 1908 specimen from Framingham, collected by C.A. Frost (as well as a 1909 specimen from Danbury, CT). W. T. M. Forbes mentions finding Harris' in the Worcester area, its stronghold today, as early as 1909 (Forbes 1909). From the 1920’s and 1930's there are MCZ and BU specimens from Weston (mostly bred, but larvae presumably collected nearby; C. J. Paine), and from Winchendon, Tyngsboro and Groton.
Farquhar (1934) lists a few eastern and central Massachusetts localities—Framingham, Princeton, Salem, Saugus, and Stoneham – and one Connecticut River valley location, Springfield. He says that Harris’ is “rare south of Massachusetts.” At the Yale Peabody Museum, there are several 1960’s specimens from West Acton by C. G. Oliver, and some from 1981 from larvae collected in the vicinity of Sturbridge by L. F. Gall. There is a 1970’s report from Holliston-Framingham (LSSS 1974).
Overall, prior to the 1986-90 MAS Atlas, evidence of Harris’s abundance or distribution in Massachusetts was decidedly spotty. There were no reports from west of “the valley,” and none from south of Boston. The Atlas confirmed that this species was rare in those regions.
Compared to pre-settlement times, the agricultural clearing initiated during the colonial era in New England may have increased wet meadow habitat for Harris’ Checkerspot (Table 1). However, the later loss of wet meadows to more intensive agriculture and to non-agricultural development, combined with the very local nature of this species, has probably resulted in some decline in its numbers since 1900 (Table 2).
Recently, the 1995-99 Connecticut Butterfly Atlas found only two Harris’ Checkerspots during intensive surveys, compared to 49 pre-Atlas records from 16 towns (O'Donnell et. al. 2007). And, the species has not been found at all since the Atlas. As a result, its status in that state was changed to S1 or “critically imperiled” (NatureServe 2010); its state rank is Threatened. Wagner (2007: 203) suggests that introduced biological control agents, such as parasitic wasps and flies, and also loss of wet meadow habitat and aerial pesticide applications, may be responsible for the disappearance of both the Harris' Checkerspot and its congener the Silvery Checkerspot (Chlosyne nycteis) from that state. The RINHS checklist for Rhode Island (Pavulaan and Gregg 2007) lists Harris’ as “status unknown,” but it is probably not present there.
Harris’ Checkerspot should be on a “watch list” for Massachusetts. We include it here as a Species of Conservation Concern. If Harris’ is indeed lost from Connecticut, Massachusetts could be next. Our current NatureServ ranking is S3, or “vulnerable.”
Host Plants and Habitat
Harris’ Checkerspot is a quintessential northern “wet meadow” butterfly. We have four such wet meadow denizens in our state, the others being Baltimore Checkerspot, Silver-bordered Fritillary, and Bronze Copper. All of these are uncommon and face loss of habitat from agriculture, development, and natural succession. They may be at further risk because of food plant specialization and/or lack of adaptability to warmer temperatures. Harris’ and the Bronze Copper are the least common.
Harris’ sole larval food plant is Doellingeria (formerly Aster) umbellatus, a tall native late-blooming composite which grows in the seasonally wet areas between strict uplands and constantly wet areas. At the continental level, the range of D. umbellatus is much wider and extends further south than that of the associated butterfly. In this state, while D. umbellatus may be found in every county (Magee and Ahles: Map 2346), the range of the butterfly is similarly not as wide as that of the food plant. Although NaturServe scientists assert optimistically that the species “is likely to colonize most good stands of its common foodplant,” in fact, Harris’ seems to require quite dense stands of Doellingeria, with females choosing only the largest plants on which to oviposit. Young larvae often denude this plant after hatching. Harris’s has only one generation a year, and the mortality of the young larvae is high, many succumbing to predators and starvation as they move away from the birth plant in search of new aster stems. Further high levels of mortality occur during winter diapause (Dethier 1959; Williams 2002). Williams estimates that it may take 500 caterpillars to produce one flying adult the next season.
Dispersal ability is critical to species such as Harris’ Checkerspot, which depend upon habitats that are subject to succession. While Doellingeria itself is a good colonizer of newly opened moist areas, Harris’ Checkerspot appears to be only a moderately active disperser (Williams, 2002), although more research needs to be done. Individual colonies tend to be small; to persist, they need to be part of a larger meta-population, so that if some patches of habitat succumb to succession, other habitats will be available nearby. Small populations at a large distance from other colonies may easily die out.
The challenge that land managers face in preserving colonies of wet meadow butterflies like Harris’ Checkerspot is that mowing must at some point be done, sometimes even annually, but it must be coordinated with the butterfly’s life cycle. Mowing should not be done until late fall, after the larvae have finished feeding and settled down into the leaf litter to overwinter. Mowing height should not be less than 6 inches.
Relative Abundance and Trend Today
The Massachusetts Atlas found Harris’ in only 24 out of the 723 blocks covered; J. Choiniere aptly termed it “uncommon and local” in his Atlas account. MBC records also rank Harris’ as “Uncommon” (Table 5). Compared to our other wet meadow species, it is seen less frequently than the Baltimore Checkerspot or the Silver-bordered Fritillary, but more frequently than Bronze Copper.
As the MBC data in Charts 46a and 46b indicate, Harris’ Checkerspot is probably now declining in Massachusetts. Supportive, or perhaps even better evidence, comes from the list-length analysis of MBC data by G. Breed et al. (2012). Breed found a statistically significant 66% decline in detectibility of Harris' Checkerspot over the 1992-2010 period. This puts Harris' Checkerspot among the fastest-declining species in the state.
Chart 46a: MBC Sightings per Total Trip Reports, 1992-2009
Chart 46b: Average Number of Butterflies per Report of Harris’ Checkerspot, 1992-2009
In Charts 46a and 46b, 1992 may be an atypical year since a very small number of trip reports (less than half the number in 1993) produced surprisingly high numbers of butterflies. Even so, the 1993-2008 trend, in which the number of trips is more comparable, still shows a significant downward slide for this species.
The results for 1992 and 1993 reflect very good numbers reported from the Holden radio tower site and the Worcester Broad Meadow Brook colony; both, but especially Holden, appear to have declined over time.
Statistics published in the MBC Massachusetts Butterflies season summaries show the same pattern of steady decline: the average number of Harris’ Checkerspot seen on a trip was down 38% in 2007, 81% in 2008, 61% in 2009, and 86% in 2010, compared to the average for preceding years back to 1994 (Nielsen 2008, 2009, 2010, 2011).
State Distribution and Locations
In the MAS Atlas, the majority of records were from central Massachusetts, with a scattering from northeast of Boston (Essex County). There were only two western Massachusetts records, in the towns of Washington (Berkshire County) and Monroe (western Franklin County), and none in the Connecticut River valley. MBC sightings records (Map 46) add more colony locations, but generally confirm the concentration of this species in central Massachusetts.
There are no MBC reports from southern Bristol County, and the single 1988 Atlas report from New Bedford could not be relocated in 2011. Searches should continue, but if Harris' Checkerspot cannot now be found in southeastern Massachusetts, then it has undergone a range contraction within the state.
Map 46: MBC Sightings by Town, 1992-2009
Harris’ Checkerspot was reported from only 37 towns 1992-2009, compared to 91 for Silver-bordered Fritillary and 74 for Baltimore Checkerspot.
In western Massachusetts, Harris’ has been reported from Sheffield (NABA Count), Stockbridge, North Adams (NABA Count), Florida, Savoy, Rowe, Heath, Plainfield, Windsor, and Shelburne; and in “the valley” from Amherst and East Longmeadow. Still, Harris’ is uncommon in “the valley,” and is surprisingly scarce further west. The western reports are few and of quite low numbers. The greatest concentrations of Harris’ Checkerspot remain in central Massachusetts.
In southeastern Massachusetts, the 1986-90 Atlas had one record: New Bedford (Bristol County) (6-15-1988, 2, M. Mello). MBC records have Bristol County reports only from Easton (6/16/1995, 50, B. Cassie), a town which is much further north. The New Bedford (Acushnet White Cedar Swamp) area was not been checked after 1988 (M. Mello, pers. comm.), but was visited on 6/8/2011 by S. and J. Stichter, who did not find any evidence of Harris' Checkerspot or its host plant. Mello and Hansen (2004) do not report Harris’ for Cape Cod. In sum, Harris’ Checkerspot may well be gone from the southeast coastal plain of Massachusetts, and is absent from the Cape and islands.
In Essex County, the MAS Atlas had reports from Ipswich, Lynnfield and North Andover. MBC records also report the North Andover colony (at Weir Hill TTOR), and add small colonies in Newbury (Martin Burns WMA) and Groveland (Crane Pond WMA). The Atlas reports from Ipswich, Lynnfield, and especially from Boston West Roxbury Highland Park, all need to be re-confirmed, since the species may well have retreated from these areas in the last twenty years.
Locations from which Harris’ Checkerspot has been recently reported in good numbers include Easton max 50 on 6/16/2005 B. Cassie; Groveland Crane Pond WMA max 6 on 7/3/2003 S. Stichter; Hubbardston Barre Falls Dam SP max 37 on 6/19/1999 T. and C. Dodd, recent max 11 on 6/23/2005 D. Price, E. Barry, J. Mullen; Lancaster Ballard Hill Recreation Area max 10 on 6/15/2004 T. Murray; Milford Rt. 85 power line max 13 on 6/8/2001 R. Hildreth; Newbury Martin Burns WMA max 22 on 6/28/2003 S. Stichter and D. Savich; North Andover Weir Hill TTOR max 21 on 6/6/2009 H. Hoople; Petersham North Common Meadow TTOR max 22 6/26/2005 E. Nielsen; Princeton Wachusett Meadow WS max 24 on 7/1/2007 Northern Worcester NABA Count; Royalston Tully Dam max 10 on 6/26/2005 C. Kamp, and Worcester Broad Meadow Brook WS max 44 on 6/12/2004 B., R., and M. Walker.
At MassAudubon’s Broad Meadow Brook WS in Worcester, Harris’ Checkerspot occurs in two areas along a power line. Since 1991, yearly counts ranging from 2 to 44 adult butterflies were made. Beginning in 2005, MassAudubon and the utility company supplemented spot herbiciding with mowing of a large part of the Harris’ habitat, since shrubs were encroaching. Results in 2006 and 2007, with high counts of 29 and 19 adults respectively, indicated that the butterfly population survived this mowing (Gach 2008). A biennial November mowing regime was then followed, and the area was mowed again in 2007 and 2009. Counts of spring post-diapause larvae, flying adults, and fall larval webs indicate that the population is persisting. However, 2010 was a very poor year for Harris’ at all monitored locations, and no June adults were seen at Broad Meadow Brook in 2010, although 2 larval webs were discovered late in the fall, and a few adults appeared in 2011 (M. Gach, pers. comm).
At the Trustees of Reservations’ Weir Hill property in North Andover, a wet meadow containing both Harris’ Checkerspot and Baltimore Checkerspot is mowed annually in late fall. The Galerucella beetle has been released to control purple loosestrife (Hopping 2009). The yearly high counts since 2004 at this site have been 20 on 6/10/2004 S. and J. Stichter; 15 on 6/11/2008 H. Hoople; 21 on 6/6/2009 H. Hoople; and 3 on 7/4/2010 H. Hoople. The numbers indicate a healthy colony. Although the year 2010 was a late and poor year for Harris’ at this and most other known locations, 5-7 adults were flying on 6/8/2011.
At North Common Meadow TTOR in Petersham, yearly high counts indicate some decline since 2004, but a bounce-back in 2011. The high counts were 16 on 6/15/2004 R. and S. Cloutier; 22 on 6/26/2005 E. Nielsen; 1 on 7/5/2006 R. and S. Cloutier; 8 on 6/12/2007 F. Model; 6 on 6/28/2008; no report 2009; 6 on 6/8/2010 B. Zaremba; but 12 adults reported 6/9/2011 by G. Breed.
The situation at WTAG radio towers in Holden is a sad example of what can happen to a Harris’ colony through butterfly-unfriendly mowing practices (Stichter, 2008). This large colony was discovered by Tom Dodd in the early 1990’s, and was visited almost yearly for many years. High counts were
30 16 June 1991 T Dodd
162 20 June 1992 T Dodd
178 19 June 1993 T Dodd
65 18 June 1994 T Dodd
200 18 June 1995 T Dodd
92 15 June 1996 T Dodd/C Asselin
37 13 June 1999 T Dodd/C Asselin
20 10 June 2002 T Moore
At first the field was mowed once in late fall “whenever they got around to it;” later, management became more intensive and mowing was done at the wrong times. The numbers of Harris’ Checkerspots plummeted. From 2002 through 2010 there were no reports, but in 2011 two larvae were discovered, indicating that the species persists but in much diminished numbers.
Broods and Flight Times
According to 1992-2008 MBC records, Harris’ Checkerspot has a short flight period, with nearly all sightings taking place in June or the first week of July (http://www.naba.org/chapters/nabambc/flight-dates-chart.asp). It has only one brood each year. Peak flight time is the last three weeks of June. It is not usually found on the NABA July Counts, unless these are held quite early in July.
Scudder (1889:681-2) wrote that the univoltine Harris’ “appears on the wing about the middle of June, continues to emerge until the end of the first week in July and flies until the first of August.” Unless Scudder’s dates are based on northern New England sites, today’s first sighting dates for the adult butterfly seem considerably earlier, and the flight also ends considerably earlier.
The Atlas earliest sighting date was 1 June 1991, Worcester, T. Dodd. MBC records have four first sightings in May, and several the first week of June: 25 May 1998, Savoy, D. Potter; 26 May 2000, Broad Meadow Brook Worcester, G. Howe; 29 May 2006, Newbury, S. Moore and B. Volkle; 2 June 2007, Milford power line, B. Walker; 4 June 1999 Amherst, D. Case; 5 June 1993, Milford power line, R. Hildreth; 5 June 1995 Easton, B. Cassie; 5 June 2001, Broad Meadow Brook Worcester, G. Howe, 5 June 2004 Milford power line, B. Walker.
The Atlas latest flight date was 15 July; MBC has no records later than this; the two latest are 14 July 1996, Princeton, T. Dodd, and 11 July 2008, Sherborn, B. Bowker. Scudder’s assertion that it flies until August may have been based on observations further north.
Harris’ Checkerspot is univoltine, is dependent on a single host plant (monophageous), experiences high larval mortality, and apparently does not disperse great distances. These facts alone go far toward explaining its relative scarcity. Add to that its limited northern distribution in eastern North America and probable vulnerability to climate warming (Table 6), and a picture emerges of a relatively fragile species.
At the southern edges of its continental range, in Tennesee, West Virginia, Maryland and New Jersey, Harris’ is ranked by NatureServe (2010) as S2 or “imperiled.” Its fragility is not confined to southern states; John Shuey recently remarked for Indiana that “...no one has seen Chlosyne harrisii in Indiana in decades; it may well be extirpated despite its S2 ranking....(Shuey 2008).”
As noted above, Harris' Checkerspot may be gone from Connecticut, where it is now ranked S1 or "critically imperilled." This example to our south should spur Massachusetts to do more to locate and conserve colonies of this species.
© Sharon Stichter 2011, 2012
page updated 1-11-2013
Species of Conservation Concern
ABOUT BOM SPECIES LIST BUTTERFLY HISTORY PIONEER LEPIDOPTERISTS METHODS