ABOUT BOM SPECIES LIST BUTTERFLY HISTORY PIONEER LEPIDOPTERISTS METHODS
The Butterflies of Massachusetts
72 Hoary Edge Achalarus lyciades (Geyer, 1832)
This distinctive skipper is uncommon in Massachusetts and may be in a downward phase. Hoary Edge is near the northern limit of its range here. It has not been reported historically or recently from Maine (MBS 2010), nor recently from Vermont, although there is at least one historic record there (VBS 2010; BMNA 2010). There are a few historic records from New Hampshire (BMNA 2010).
Scudder wrote that Hoary Edge was a “rare insect” in New England, confined to the southern portions of the region. “Uncommon” might have been a better characterization, because Hoary Edge had “occasionally occurred in abundance in New Haven and vicinity,” had been found in Plantsville and New Britain, Conn., and “two or three are taken every season near Springfield [Mass.]”. H. W. Parker caught a male on Mt. Holyoke on June 25, 1874, the first to be found in the Amherst area (Parker 1874), and F.H. Sprague took one the last of July, 1878, in North Leverett (Sprague 1879). Thus, it may have been moving up the Connecticut River valley at this time. Scudder also reports it from the vicinity of Boston, where single specimens had been taken at rare intervals in such places as Waltham, Winchester, and Wollaston (now in Quincy). Scudder even reports three or four specimens from Milford, N.H., a location not far from Nashua in the Merrimack River valley (1889: 1421).
Photo: Great Blue Hill, Canton, Mass., E. Nielsen, June 29, 2008
John Abbot in Georgia was the first to figure this species, saying that it “Feeds upon the Beggars lice (so called from the seeds sticking to people’s Clothes).” He showed the caterpillar feeding on a species of Desmodium (Calhoun 2006; but see also Scudder 1889: 1422). With the clearing for agriculture in New England between 1600 and 1850, Hoary Edge may have increased in this region, or arrived here at that time (Table 1), although there is little actual evidence. It’s open-area legume host plants undoubtedly increased.
By 1934, Farquhar was able to list specimens from several additional towns around Boston: Stoneham (C.V. Blackburn, collector), Sherborn (E. J. Smith, coll.), Melrose (R. W. Harris, coll.), Middlesex Fells (C. A. Frost, coll.), and Medford (J. H. Rogers, coll.), widening the circle of locations from which Hoary Edge was known.
Hoary Edge seems to have been increasing during the 1960’s and 1970’s, when it was extensively reported in the Lepidopterists’ Society Season Summaries. The main reporting locations were still in eastern Massachusetts and the lower Connecticut River valley. Increasing urbanization and perhaps attendant warming in those areas may have been facilitating an increase in this species (Table 2). Charles D. Oliver observed three in Belmont in July 1965. Edward M. Peters captured one male on July 15, 1971 in Carlisle, but said that while Silver-spotted Skipper was quite common there, Hoary Edge was not.
In 1973 J. Levy and R. Robbins found several Hoary Edge June 12 through July 4 at Medford's Middlesex Fells reservation, a location from which this skipper had been known from the 1930s. And Patrick Carey of South Hadley submitted an extensive report covering the Springfield area. He collected a Hoary Edge “at the base of the hill [Cedar Knob, Holyoke], out of the woods, visiting flowers, in late June.” In 1972 N. Franks collected a Hoary Edge in Wellesley on July 19, and in 1974 William D. Winter collected a Hoary Edge in Sherborn on July 22. Both these specimens are now in the Harvard Museum of Comparative Zoology.
The 1974 and 1975 seasons saw Hoary Edge particularly well reported, with notes from R. Robbins calling it “high and expanding” in 1974 and “common” in 1975. Darryl Willis, reporting for the Holliston-Framingham (Middlesex Co.) area, found Hoary Edge “becoming common, noted ovipositing on tick trefoils” in 1974. Willis did most of his collecting in what is now referred to as the Sherborn power line area. He found a total of 72 species there, and once (July 4, 1975) took specimens of 48 species there in one day! The power line remains a productive habitat today, and was much frequented by MBC members 1990-2010.
Willis reported A. lyciades “still not uncommon” late May to late July, 1975, noting that “Apparently, this species is well-established. It will be interesting to see if it can weather the severe winter of 75-76” (letter to Paul Grey, 2/4/76; Lep. Soc. Seas. Sum. and Correspondence, 1959-1976). Apparently it did, since Deane Bowers found it at Montague June 20, 1976 (Lep Soc Seas. Sum. 1976). This was the northernmost report in Massachusetts at that time.
Host Plants and Habitat
Hoary Edge’s caterpillar host plants are mainly various tick-trefoils, especially Showy Tick-trefoil (Desmodium canadense), which is quite common in our area, but also bush clovers (Lespedeza spp.) and other legumes. Scudder (1889:1422) gives a good description of the caterpillar’s way of using Desmodium, stitching together two nearby leaves toward the top of the plant, then leaving the nest and moving downward as it needs to make use of larger leaves.
During the 1980’s Massachusetts Atlas period, Tom Dodd observed Hoary Edge ovipositing on Panicled Tick-trefoil (D. paniculatum) and Round-headed Bush Clover (Lespedeza capitata). Additional evidence as to New England host plants comes from the 1995-99 Connecticut Atlas, whose field workers found Hoary Edge eggs or caterpillars in the wild on Tick-trefoils (Desmodium spp.), bush clovers (Lespedeza spp.), Wild Indigo (Baptisia tinctoria), and Groundnut (Apios americana) (O’Donnell et al, 2005).
Showy Tick-trefoil is found in every county in Massachusetts, including the Cape and Islands. In addition there are 11 other tick-trefoils in the state, some also widely distributed (Sorrie and Somers, 1999; Magee and Ahles, 1999).
Hoary Edge prefers dry, upland areas, open dry sandy woodlands, and woodland edges. But it ranges widely in search of nectar; nineteenth century collectors like Scudder found it on butterfly weed and garden phlox; today we find it on common milkweed and dogbane. It often basks on exposed soil, defending its territory.
Relative Abundance Today
MBC records 2000-2007 rank Hoary Edge toward the lower end of “Uncommon,” about on a par with Southern Cloudywing and Sleepy Duskywing (Table 5). It contrasts with Silver-spotted Skipper, which is “Common.” The 1986-90 MAS Atlas also ranked Hoary Edge as Uncommon, having found it in only 28 out of the 723 atlas blocs searched. MBC records show it in 52 towns out of a possible 315.
Hoary Edge may have been expanding in the 1960's and 1970's, but it appears to be declining today. MBC sightings per total trips (Chart 72) indicate a sharp decline in the relative abundance of Hoary Edge over the last 19 years. There was a decline in sightings from 1992 to 1996, then an increase 1996-1999, and fairly steady decline thereafter. 1999 was a banner year for all spread-wing skippers, including Silver-spotted, Juvenal’s and Horace’s Duskywings, and Sleepy Duskwing, as well as Hoary Edge. That year 50 Hoary Edge were reported on the Truro (Outer Cape) NABA Count (the only MBC report from Cape Cod in 19 years), and 25 at Fruitlands Museum in Harvard, Mass. It has not been reported from either of these locations again, despite searches.
Chart 72: MBC Sightings per Total Trip Reports, 1992-2009
A slightly different calculation using the same data also indicates recent decline in Hoary Edge sightings. In 2007, 2008, and 2009, the average number of Horace’s per trip report decreased 32%, 57%, and 82% relative to the average for the preceding years back to 1994. The number of reports of this species, and the maximum number reported, were also down in 2008 and 2009 relative to prior years (Nielsen, Season Summary, MB 2008-2010, No. 30, 32, 34).
State Distribution and Locations
Map 72: MBC Sightings by Town, 1991- 2010
The 1980s Atlas had found Hoary Edge “in a swath from northeast to south central Massachusetts with no records from western, north central, most of southeastern Massachusetts, or Cape Ann, though many of the areas where it was unrecorded were well covered during the Atlas.” Thus, the skipper had been found in some of the more highly developed areas of the state, but was apparently absent from the southeast coastal plain, and Cape and the islands.
The picture presented by MBC data is similar, except that Hoary Edge is now reported from much further north up the Connecticut River valley (notably Montague area), from more towns in central Massachusetts (notably Worcester and Princeton), and from Carver (Myles Standish SF) in southeastern Massachusetts .
In the upper Connecticut River valley, there are now Hoary Edge records from Montague (1993, 1, M. Fairbrother; 2000, M. Mello), Greenfield (1995, 2, M. Fairbrother), Gill (1999, 2, Butterfly Institute), and Leominster (2008, 1, R. Hopping), as well as Bowers' 1976 report. In addition, the skipper has been found in small numbers (1 – 7) every year from 1999 to 2009 (11 years running) on the Montague-based Central Franklin County NABA Count.
In the northeast (Essex County), MBC records add Boxford and Newbury to the Atlas reports from Andover, North Andover and Newburyport. These are the northernmost reports for New England at this time. Oddly, there are still no reports from Cape Ann, despite searches throughout the period by D. Savich and C. Tibbits.
Hoary Edge is still not found in Berkshire County, nor on Martha’s Vineyard or Nantucket: neither BMNA (2010), the 1986-90 Atlas, nor the 1991-2009 MBC records have any reports from these areas. The only MBC report from the southeast (Plymouth and Bristol Counties) comes from Myles Standish SF, and the only Barnstable County report is of 50 on the Truro NABA Count in the boom year 1999. Mello and Hansen (2004) do not mention Hoary Edge as occurring on the Cape.
The July NABA Counts usually catch this species if it is present. Hoary Edge has never been reported from any of the three long-running Berkshire Counts, nor from either the Vineyard or the Bristol County Counts. By contrast, it is regularly reported from the Blackstone Valley Count (max 18 in 7/14/2001), from the Foxboro, Lower Pioneer, Central Franklin, and Northern Worcester Counts, and a few times from the Concord Count.
Hoary Edge is usually seen in small numbers at any one site, with no more than 5 reported from any one location. One exception was the boom year of 1999 (Chart 72), when 12 were reported in Sudbury on 6/20/99 (R. Walton), 25 at Fruitlands Museum in Harvard on 6/30/99 (J. Choiniere), and an unusual 50 reported from the Truro (Outer Cape) NABA Count on 7/17/99. 2001 was also a good year for Hoary Edge, with 10 reported from Broad Meadow Brook Sanctuary in Worcester (G. Howe, 7/1/2001), and 9 from the Rt. 169 power line in Charlton (R. Hildreth, 7/2/ 2001).
Other sites with notable and recurring sighting numbers are Horn Pond Mountain in Woburn (max. 7 ,7/12/2002, A. McGinnis); Dauphinaise Park in Grafton (max. 3, 6/29/2002, D. Price et al.); Great Blue Hill in Canton (max. 6, 7/8/2006, M. Champagne and E. Nielsen), and Mary Cummings Park in Burlington (max. 3 on 7/4/2007, E. Nielsen).
Broods and Flight Time
According to the MBC flight chart, based on 1993-2008 sight data, Hoary Edge flies from the first week of June through the first week in August; peak flight time is the third week in June through the third week of July ( http://www.naba.org/chapters/nabambc/flight-dates-chart.asp).
Scudder (1889: 1422) reported the earliest appearance of Hoary Edge as “rarely before the first of June about Boston,” so that today’s first flight time does not seem to differ very much. South of Massachusetts, in Connecticut, the flight time begins in the latter half of May, as Scudder also noted (O’Donnell et al., 2005).
The earliest sight reports in 19 years of MBC records are 6/5/2004, Milford power line, B., R. and M. Walker; 6/6/2009 Westborough, S. Moore and B. Volkle; 6/7/2001 (8 seen) Charlton Rt. 169 power line R. Hildreth; 6/9/1991 Worcester T. Dodd; and 6/9/2002 Sunderland, T. Gagnon. Aside from these five years, the other 14 first sightings were between 6/10 and 6/25. There is no noticeable tendency toward earlier first sightings.
In the 19 years 1991-2009 the latest sightings have been 8 August 1991 Woburn R. Walton (Atlas report); 5 August 2000 Norfolk B. Bowker; and 3 August 2003 Canton Great Blue Hill E. Nielsen. Scudder (1899: 1422) had indicated that Hoary Edge flew “until about the middle of July; but all July specimens are invariably worn and battered.” The mid-July date accords with today’s peak flight time, but the small number of recent MBC observations in August do seem to indicate some extension of the flight period compared to a century ago.
Current and historical sources indicate that Hoary Edge has only one brood in Massachusetts, and thus far there is no evidence of a partial second brood. Opler and Krizek (1984:203) indicate that only in the deep South is this species fully bivoltine; Allen (1997) reports a partial second brood in West Virginia in warmer areas at lower elevations.
Hoary Edge is multiphageous, using several very common weedy host plants, but has not adopted an aggressively spreading host as has the Silver-spotted Skipper. Also unlike Silver-spotted, there is no evidence of a second brood. The fact that Hoary Edge is strongly univoltine in this climate limits its abundance here. It is probably limited both by cold winter temperatures and by the length of the warm season.
Climate warming could lead to some increase in numbers in Massachusetts, but Hoary Edge may not become common. Its recent downward slide suggests the need for more careful field searches and monitoring of known occurrences. It’s present NatureServe rank of S4 here may not be warranted.
© Sharon Stichter 2010, 2011
page updated 11-16-2011
ABOUT BOM SPECIES LIST BUTTERFLY HISTORY PIONEER LEPIDOPTERISTS METHODS