Butterflies

Butterflies and Skippers (PAPILIONOIDEA)

Butterflies and skippers constitute a Superfamily (Papilionoidea) in the Order Lepidoptera of the Class Insecta. The vast majority of this order (44 or 46 recognized superfamilies) are moths, which represent the basal portions of the phylogenetic tree. Butterflies are therefore, in a sense, nested within moths the way rabbits are nested within mammals. Butterflies (including skippers) and moths are generally distinguished only by anatomical features. In general, butterflies and skippers are diurnal fliers with clubbed antennae and, excepting most skippers, tend to have colorful wings, although many species of moths are also colorful and diurnal. The precise features used to discriminate families of Lepidoptera in our region are aptly treated in field guides (e.g. Covell, 2005). An exceptionally good and detailed discussion of life history, ecology, evolutionary history, fossil record, etc., appears in Scott (1986). An extensive list of plants which are the internet websites also contain useful caterpillar host plant information and faunistics.

Worldwide, there are an estimated 180,000 species of Lepidoptera, including about 14,750 species of butterflies. In North America there are an estimated 679 species of butterflies, 416 in the Superfamily Papilionoidea (true butterflies) and 263 in the Superfamily Hesperioidea (skippers) (Scott, 1986). Massachusetts has about 125 known species of butterflies. This compares to 82 species now known for Martha’s Vineyard. Only 19 species have been found on Nomans Land Island National Wildlife Refuge, a 628-acre satellite island off the southwest corner of Martha’s Vineyard which is part of the Town of Chilmark.

The butterflies of our region can in general be identified by sight under field conditions by skilled observers, and this list accordingly incorporates many sight records from recent decades. That said, documentation of rare species by photograph is desirable, and photos or specimens of any proposed additions to this list would be most welcome. As noted below, a few sight records of species not otherwise documented here, and for which confusion with other species is possible, have been excluded.

The most comprehensive study of the Lepidoptera of Martha’s Vineyard and Nantucket is that of Jones and Kimball (1943), cited as “LNMV” in the checklists included here. These authors reported 65 species of butterflies for the Vineyard and 53 from Nantucket. This study was also the first to discuss in any detail the zoogeographical affinities of the species found here. They concluded that the “number and variety of species present is rich and varied.” After comparison with the faunas of Maine’s Mt. Desert Island, Connecticut, Virginia, and central coastal New Jersey, they concluded that the Vineyard’s resident species have a southern bias as a group. They also emphasized that food plants determine the composition of the resident fauna and that the arrival of new food plants within historical times has allowed the colonization of new species, though in some cases a few butterfly species have not arrived even though their host plants are present, even abundant.

Notable changes in population size and distribution for certain species deserve comment. Pipevine Swallowtail (Battus philenor) apparently occurred reasonably often and even bred formerly (Jones and Kimball, 1943); today it is a rare visitor. Orange Sulphur (Colias eurytheme) was apparently a rare straggler to the island prior to 1930, around which time it became common to abundant and widespread; so it continues today, with a certain amount of annual variation following very severely cold winters. Little Yellow (Pyrisitia lisa) was “well distributed, sometimes far from rare” (Jones and Kimball, 1943) in the 1940s and occasionally bred; only two sightings have been recorded in the last 20 years, neither documented by a photograph or specimen. The Regal Fritillary (Speyeria idalia) was “frequent” in “Chilmark and Gay Head” in 1940 and moderately common in Chilmark until the 1960s (Jones and Kimball, 1943) but was extirpated from the island by 1987. Strangely, the five remnant populations of Regal Fritillaries prior to their extirpation from New England all occurred on the offshore islands: Martha’s Vineyard, Nantucket, Naushon, Noman’s Land, and Block Island.  These populations had all disappeared by 1992 (Goldstein, 1992a; Wagner et al., 1997).  The Silver-bordered Fritillary (Boloria selene) was widespread and moderately common in the 1940s (Jones and Kimball, 1943:30) but there are no recent reports at all. Mourning Cloak (Nymphalis antiopa) appears to have become more numerous and widespread than it was in the 1940s.

There are no convincing recent records for Eyed Brown (Satyrodes eurydice); it was reported by Jones and Kimball (1943), but that was before this species was taxonomically separated from Appalachian Brown (S. appalachia). It is possible that Eyed Brown did occur when there was much more grassy pasture habitat on the island in the 1850-1940 period than there is today, but lacking specimen evidence, we prefer to leave Eyed Brown off the list. There are a few sight records for Delaware Skipper (Atrytone logan) but no indication of an established population here; while this species could occur as a vagrant, it is not known for vagrancy, and the possibility of confusion with lightly marked Long Dash (Polites mystic) or Indian Skipper (Hesperia sassacus) makes documentation by a specimen or good photograph prudent for this species to be included here. There is also a 2001 sight record for Hickory Hairstreak (Satyrium caryaevorus); it is not accepted here because of the rarity on the Vineyard of its usual food plant and the range of variation that occurs in Banded Hairstreak (S. calanus). A specimen or diagnostic photograph seems called for to include S. caryaevorus here.

Several species have been added to the Vineyard checklist in recent years. An American Snout (Libytheana carinenta) was collected in Aquinnah in 2010, still the island’s only record for this unique butterfly. Giant Swallowtail (Papilio cresphontes) was first recorded here in 2012, in West Tisbury, and there have been a few subsequent records. This species appears to be extending its range in the Northeast and can be expected to be an increasingly common visitor. Giant Swallowtail appears unlikely to become established as a breeder here, however, because its presumed host plant in our region, common prickly ash (Zanthoxylum americanum), does not occur on the Vineyard. Red-banded Hairstreak (Calycopis cecrops), a southern species gradually expanding its range northward, was first documented on the Vineyard in 2016, in Edgartown; the species has been photographed with increasing regularly subsequently, with most records coming from Tisbury and West Tisbury. Zabulon Skipper (Lon zabulon), another species engaged in northward expansion, appears to be established here and can be expected to become increasingly common. The long-awaited first Vineyard record for Long-tailed Skipper (Urbanus proteus) came in 2023. Not yet recorded on the Vineyard but possible (one might even say overdue) is Ocola Skipper (Panoquina ocola), a late-season migrants from the South that has become quite regular in mainland Massachusetts (tantalizingly, there are Cape Cod records).

In addition to the references cited above, other useful publications are Opler and Krizek (1984), Opler (1992) and Glassberg (1999) for identification. Pyle (1992) is a good general handbook of information about butterflies.

Allan Keith; edited by Matt Pelikan,  December 20, 2023