ABOUT BOM SPECIES LIST BUTTERFLY HISTORY PIONEER LEPIDOPTERISTS METHODS
The Butterflies of Massachusetts
91 Indian Skipper Hesperia sassacus Harris, 1862
Thaddeus W. Harris named this skipper after the last important chief of the large Pequot nation based in Connecticut. The English attacked and decimated the Pequots in 1636; Sassacus escaped with a small group of Pequots, but was later killed by the Mohawks in 1637.
The “Sassacus Skipper” (along with Leonard’s and Hobomok) is one of the upland grass skippers which Scudder and Harris described as very common in Massachusetts in the 1860’s, but which are not so today (Table A). These skippers probably increased here after 1600 with the expansion of agriculture (Table 1), but have for some reason declined in abundance since the late 1800’s--- in contrast to the Peck’s, Least, and Dun Skippers, which Scudder also described as common, and which remain fairly common today (Table 2). All of the species which have declined are single brooded, that is, they have not adapted to a longer growing season by having two broods, and thus have only one chance a year to increase their numbers---whereas the other three are multi-brooded. This is a significant factor in assessing the future outlook for these species.
Photo: Athol, Mass., F. Model, May 25, 2010
The Indian, Hobomok and Leonard’s are open upland skippers because of the grasses which are their larval host plants, but they also need nectar sources which are often in nearby wetland areas. The other uncommon Massachusetts skippers in this “upland” category are Cobweb, which Scudder described as “not abundant” in his day, Dusted, which to Scudder was “known from but a few localities” and Crossline, for which Scudder had ten specimens, and which was probably uncommon (Table A). Four of these six skippers (all except Dusted and Crossline) are “seasonally targeted” (Cech 2005), that is, they are univoltine, and their range does not presently extend into the U.S. southeastern coastal plain. This characteristic limits their adaptability to climate warming.
Indian Skipper has a fairly small range, flying in the northeastern states, around the Great Lakes and north into Canada, but west only to Saskatchewan and Minnesota, and south of Pennsylvania only in the interior mountains (BMNA 2010; Opler and Krizek 1984). There is no southeastern coastal range south of New Jersey.
Harris described Indian Skipper in 1862 from a female specimen “which was taken in Cambridge in the month of June” (1862: 315). The present location of this specimen is unknown (Miller and Brown 1981:37). Scudder described the male in the same year. Scudder is able to list specimens from quite a number of locations. and says that in the vicinity of Boston, Indian Skipper was “ very common in such localities as Malden, Winchester, Prospect Hill and Turkey Hill, Milton, and Walpole,” as well as being found in Andover, in Springfield and Williamstown, and on Cape Cod (1889: 1644). F. H. Sprague took a long series of specimens at Wollaston (Quincy) in June 1878, and says that the date of its first appearance there that year was May 22 (Psyche 1879). Maynard (1886) says “This is one of the most common Skippers. Occurs in June on the margins of woodlands...”
Indian Skipper may have continued to be fairly easy to find through the 1930s, because Farquhar (1934) is able to list specimens from eight additional locations: Stoneham, Marblehead and Lawrence in the east, Princeton, Phillipston, Framingham, Worcester, and Gilbertville (near Quabbin Reservoir) in central Massachusetts, and Mt. Holyoke and Amherst in “the valley.” (The Framingham specimen, 4 June 1904 C. A. Frost, is at BU; the Stoneham specimen, 2 June 1930, C. V. Blackburn, is at Yale. ) However, Indian Skipper was not found on either Martha's Vineyard or Nantucket at this time (Jones and Kimball 1943).
In the 1950's and 1960's, Indian Skipper was found around Acton, and in Littleton, Belmont, Wellesley and Waltham (specimens at Yale Peabody Museum, mostly C. G. Oliver). D. W. Winter found Indian Skipper in Millis and Westwood in the 1970's, and E. M. Peters found it on 26 May 1971 in Carlisle ((specimens at Harvard MCZ; Lep.Soc.Seas.Sum and Corrsp., 1959-1981). Indian Skipper does not appear to be as common in this period as it was in Scudder’s time (Table 2).
Host Plants and Habitat
Little Bluestem (Schizachyrium scoparius), Panicum spp, and Festuca spp. (rubra and obtusa). are the most definite and frequently-reported host grasses, with other species likely (Scott 1986; Opler and Krizek 1984). All these are native grasses in Massachusetts. The larvae will accept Kentucky Bluegrass in the lab. The Connecticut Atlas raised Indian Skipper on Little Bluestem, Kentucky Bluegrass (Poa pratensis), and other Poa species. Indian is apparently not as restricted to Little Bluestem as are the “Little Bluestem Trio” of Cobweb, Leonard’s and Dusted. For example, R. Godefroi reported Indian Skipper ovipositing on Agrostis spp. in Medford, Massachusetts in June 1987 (Lep Soc. Seas. Sum. 1987). Being multiphageous could signal adaptability, but research is needed to confirm the precise grass species in use in our area.
Indian Skipper’s habitat is usually described as “dry, often rocky or sandy grassy fields, right of ways, burn scars, meadows and openings in wooded areas.” Most characteristically, it is “a species of dry, generally wooded, usually hilly, countryside found with patches of native grasses, but often on disturbed areas” (NatureServe 2010). Walton, in the 1986-90 MAS Atlas, mentions “old fields, abandoned pastures, forest clearings, and powerline cuts.”
Indian Skipper can also be found in wet meadows, nectaring along with other meadow skippers such as Long Dash and Peck’s (Cech 2005; Layberry 1998).
Of the six dry land skippers in Table A, Indian and Hobomok are more likely to be found associated with forest openings or edges than are the other species.
Relative Abundance Today
Our three Hesperia skippers ---Indian, Cobweb and Leonard’s--- are all about equally Uncommon in Massachusetts today, as measured by MBC sightings 2000-2007, and they were all similarly ranked during the Atlas years ( Table 5). Of the six “dry meadow skippers" in Table A, Hobomok and Dusted are somewhat more common.
MBC sightings of Indian Skipper 1992-2009 (Chart 91) show a downward trend 1995 through 2009. There are fluctuations every few years. The high reading for 1995 is due to two reports of especially large numbers (82, 65), at Middlesex Fells Reservation, Medford, in what may have been a local population explosion. Other instances of high local populations are in the records, although no other reports from single locations exceed 50. Excluding the two high 1995 reports would reduce, but not eliminate, the downward trend.
Chart 91: MBC Sightings per Total Trip Reports 1992-2009
State Distribution and Locations
Map 91: MBC Sightings by Town, 1992-2009
Indian Skipper has been found in 89 towns 1992-2009, according to MBC records. Cobweb Skipper, in these years, has been reported from only 54 towns.
Indian Skipper seems always to have been most easily found in the eastern and central three-quarters of the state, and is less common in the Berkshires and on the coastal plain. The Atlas found it apparently absent from large portions of southeastern Massachusetts, including Cape Cod and the Islands. There were also no Atlas records from southern Berkshire County, and very few from the central part of the state.
MBC data fill in many gaps in the distribution across the state, compared to the Atlas, particularly in the central areas north, south and west of Worcester. There are still very few reports from Berkshire County (only Egremont, New Marlborough, and Williamstown, and it has not been found on any of the Berkshire NABA Counts). There are also no reports from many southeastern towns, particularly the Taunton River drainage area and Westport/Dartmouth.
Indian Skipper is not common on Cape Cod, according to MBC records, but has been reported from Crane WMA in Falmouth, as well as Truro and Scusset State Beach in Sandwich. Mello and others did find at least 35 in several fields at Crane WMA on 6/28/1998 during a survey for rare lepidoptera (Mello et. al, 1999). However, Mello and Hansen (2004: 61) remark that overall Indian Skipper appears to be less common than Cobweb on Cape Cod.
On Martha’s Vineyard, Indian Skipper is now clearly present, in contrast to earlier reports. (The 1986-90 Atlas, and Jones and Kimball in the 1940's, had not found it.) Indeed, the Vineyard appears to be a haven for all three uncommon Hesperia Skippers -- Indian, Cobweb, and Leonard’s. The Vineyard checklist ranks Indian as “Uncommon” (Pelikan, 2002), but there are numerous MBC reports, for example, Tisbury Meadow, max. 31, 6/16/2003 M. Pelikan; Tisbury Vineyard Haven max. 29, 6/1/2002, M. Pelikan; and Oak Bluffs Farm Pond, max. 7, 6/15/2003 M. Pelikan. There are still no reports of Indian Skipper from Nantucket. Indian was also not found on recent surveys of the Elizabeth Islands or the Boston Harbor Islands (Mello 1998, 2003).
Except for a few locations with short-term population build-ups, Indian Skipper is not usually found in large concentrations, but rather in small numbers. One particular hotspot, Middlesex Fells Reservation in Medford/Stoneham/Winchester, warrants revisiting. D. F. Schweitzer documented Indian Skipper there in June 1987 (specimens at Yale), and a high of 82 was reported there on 6/4/1995 by B. Malcolm, but there have been no more recent reports.
Localities with particularly high numbers or consistent reports are
Canton Great Blue Hill max. 4, 6/13/2004, E. Nielsen; Chelmsford, max. 11, 6/2/1999, C. Dodd; Deerfield, max. 8, 6/4/1996, D. Potter; Foxborough, many reports, max. 7 on 5/31/1993, B Cassie;; Holliston Brentwood CA, max. 8 on 5/31/2009, B. Bowker; Hubbardston MDC property, max. 11 on 6/2/2001 D. Small; Hubbardston Barre Falls Dam max 6 on 6/6/1999 T Dodd and C Dodd; Lexington, max. 15, 6/11/1997, M. Pelikan; Monson, Norcross WS, max. 4 on 6/13/2006, J. Ohop and E. Barry; Northampton Florence, max. 141 on 5/30/2011 T. Gagnon; Plymouth Myles Standish SF, max. 9 on 5/23/2009 MBC T Murray; Royalston, max. 8, 6/16/2003, C. Kamp; Sherborn power line, max. 5 on 6/13/2004 E. Nielsen; Uxbridge West Hill Dam, max. 8 on 5/31/1999, T and C Dodd; West Boylston Gate 36, max. 8 on 6/17/2001, M. Lynch and S. Carroll; West Tisbury Nat's Farm, 18 on 6/4/2010 M. Pelikan; Worcester Broad Meadow Brook WS, max. 4 on 6/5/2001, G. Howe.
Broods and Flight Time
As noted, Indian Skipper is univoltine---probably obligate univoltine. It flies early, from the third week in May to mid-July, with the largest numbers seen from the last week in May through the third week in June (http://www.naba.org/chapters/nabambc/flight-dates-chart.asp).
Scudder wrote that the earliest Indian Skippers were seen “during the last week in May, the female scarcely later than the male” (1889: 1645). In four of the 19 years of MBC data (1991-2009), there have been first sightings prior to May 23—earlier than Scudder’s date. The MBC first sightings prior to 5/23 are 5/17/2000 Sherborn, R. Hildreth; 5/20/2008 Petersham North Common Meadow TTOR, R. and S. Cloutier; 5/21/2009 Northampton Florence T. Gagnon; and 5/22/1999 Uxbridge West Hill Dam, T. and C. Dodd. The Atlas earliest date was also a bit earlier than Scudder’ timing: 5/20/1986 Medford D. Schweitzer. So there may be a slight tendency toward earlier emergences, but in 13 of the 19 years 1991-2009, Indian Skipper has first been seen remarkably regularly during the last week of May.
In 2012 the second earliest sighting in MBC records was recorded: 5/19 at Chelmsford power line, B. Bowker.
The July NABA Counts sometimes pick up the latest-flying Indian Skippers. Late dates in MBC records are 7/13/2003 North Essex NABA Count (Martin Burns WMA); 7/11/2008 Newbury Old Town Hill TTOR S. and J. Stichter; 7/9/2000 Princeton (Northern Worcester NABA Count) T. and C. Dodd; 7/7/1996 Foxborough NABA Count; 7/6/1997 Foxborough NABA Count, 7/3/1992 Foxborough, B. Cassie, and 7/1/2006 Mt Greylock M. Lynch and S. Carroll. As can be seen, late dates for small numbers of Indian Skippers now extend to mid-July, beyond the Atlas late date of 6/28/88. But Scudder had also noted that “sometimes battered individuals may be found until the middle of July (1889: 1645)”
Overall, there is no strong evidence of a tendency toward earlier or later flight dates since the turn of the century.
The outlook is not rosy for this species. Indian Skipper should be considered a Species of Conservation Concern in Massachusetts. Indian Skipper’s lack of a southern low-elevation range and cold-adapted univoltine life style both suggest that it may be adversely affected in Massachusetts by climate warming (Table 6).
The 1990-95 Connecticut Atlas did not find strong evidence of a decline of Indian Skipper in that state, but there were only 40 project records found compared to 72 pre-project, suggesting some decline. The species is ranked S3S4 there and S4 in Rhode Island and Massachusetts (NatureServe 2010), but these ranking may need to be re-visited. Around the southern and western edges of its small range, for example in Tennessee (S1), Illinois (S2), Indiana (S2), and Saskatchewan (S1), Indian Skipper is presently most threatened.
Indian Skipper should benefit from preservation of the same kinds of inland dry grassy habitats that are needed by Cobweb, Leonard’s, Crossline and Dusted Skippers. It probably uses several species of grass within these habitats, and research is needed to pinpoint which grass species are the local hosts. Though not rare in our state, this is one species which needs monitoring. Proactive measures should be taken to prevent decline at known sites.
© Sharon Stichter 2010, 2011, 2012
page updated 9-9-2012
ABOUT BOM SPECIES LIST BUTTERFLY HISTORY PIONEER LEPIDOPTERISTS METHODS