The
Red Admiral, Vanessa atalanta, is a common and cosmopolitan
Holarctic butterfly of the family Nymphalidae. It inhabits North
America from central Canada through the Mexican highlands to
Guatemala (Opler, 1992). Typical habitat is rich, moist bottomland
woods containing larval host plants such as stinging nettle
(Urtica dioica) and false nettle (Boehmeria
cylindrica). V. atalanta is typically found in sunlit
forest openings or margins (Opler and Krizek, 1984), often in or near
stream courses; in moist fields, in city parks, and on ridge tops
(Opler, 1992). The dorsal side of the wings is dark brown to black.
The forewing has small white apical spots and a prominent red-orange
median band, and the hindwing has a red-orange marginal band. V.
atalanta's wing span varies from 58 to 76 mm (Opler, 1992); the
male forewing length ranges from 2.6 to 3.3 cm (mean = 3.1 cm).
Females are slightly larger than males: forewing length ranges from
2.9 to 3.5 cm (mean = 3.2 cm) (Opler and Krizek, 1984). Although
V. atalanta shows little morphological variation over its
geographic range, it has distinct summer and winter forms. The summer
form is larger and brighter, with an interrupted forewing band,
whereas the winter form is smaller and duller in color (Opler and
Krizek, 1984). V. atalanta is double-brooded throughout most
of its range (Opler and Krizek, 1984). It is single-brooded in the
northernmost United States and Canada, and triple-brooded in the
southern states. In Iowa, V. atalanta is active from mid to
late April to late September or early October. V. atalanta is
seasonally migratory (Opler and Krizek, 1984; Opler, 1992). It
probably cannot survive colder winters in the northern part of its
range (Opler, 1992), although Shapiro (1974) reports that adults
hibernate successfully as far north as New York. It overwinters in
the southern states, including south Texas (Opler, 1992) and Florida
(Swanson, 1979; Swanson and Monge-Nájera, 2000).Photo by Kirsten Mortensen, Rochester, New York, taken on the morning of July 9, 2004. The butterfly was sunning itself in a garden where some daisies and echinacea were in bloom.
The
Painted Lady, Vanessa cardui, is the most widely distributed
butterfly in the world (Opler and Krizek, 1984; Scott, 1986). It is
found throughout Europe, Asia, Africa, North America, and Central
America. It is not a permanent resident in the eastern United States,
but quasi-periodically migrates there from the deserts of the
southwestern U.S. and northern Mexico (Opler and Krizek, 1984). These
migrations are sporadic and often enormous, and often follow rainy
periods in these deserts. Scott (1986) recognizes two subspecies:
V. cardui cardui is found throughout North America south to
Venezuela and throughout the Bahamas and Antilles; throughout Eurasia
including India and Ceylon, and Africa including Madagascar. The
other, V. c. kershawi, occurs in Australia and New Zealand and
strays into Fiji. Hawaiian V. cardui adults are intermediate
between the two subspecies, and both forms can develop from the eggs
of a single female (Scott, 1986). According to Opler and Krizek
(1984), V. cardui prefers open areas, including old fields,
vacant lots, and gardens. I have found that in Iowa, V. cardui
prefers more open areas such as prairies and fields, whereas V.
atalanta prefers forest margins and parklike areas with more
trees. Painted Lady larvae feed on a wide variety of host plants of
the families Compositae (especially thistles), Boraginaceae,
Malvaceae (especially the hollyhock Althaea), common mallow
(Malva neglecta), and a number of legumes (Opler and Krizek,
1984) including Iowa soybeans (Scott, 1986) The dorsal side of the
wings is orange-patterned. On the underside of the hindwing are five
small submarginal eyespots. Females are generally larger than males.
Male forewing length ranges from 2.5 to 3.3 cm (mean = 3.0 cm);
female forewing length ranges from 3.0 to 3.4 cm (mean = 3.2 cm)
(Opler and Krizek, 1984). V. cardui, like V. atalanta,
has distinct summer and winter forms. The summer form is larger and
brighter and has blue pupils in the submarginal spots on the dorsal
hind wing (Opler and Krizek, 1984). The winter form has entirely
black wing spots. The number of broods in any one place may vary from
year to year because it is not a permanent resident in most of the
U.S. (Opler and Krizek, 1984).
The
American Lady, Vanessa virginiensis, inhabits North America
from southern Canada through the entire United States, as well as the
mountains of Central America, Colombia, and the Galapagos Islands
(Opler, 1992). Typical habitat includes open areas with low
vegetation, such as meadows, floodplains, vacant lots, and beach
dunes (Opler and Krizek, 1984; Opler, 1992). The larvae, unlike those
of the Painted Lady, feed on a comparatively limited range of
foodplants. The preferred food sources are plants of the everlasting
tribe of the Compositae, such as sweet everlasting (Graphalium
obtusifolium), pearly everlasting (Anaphalis
margaritacea), and plantain-leaved pussytoes (Antennaria
plantaginifolia); they also feed occasionally on burdock
(Arctium), wormwood (Artemisia), and ironweed
(Vernonia) (Opler and Krizek 1984; Scott 1986). The dorsal
side of the wings is orange-patterned, and a small white spot in the
center of the cubital cell of the forewing is a distinguishing
characteristic of this species. The American Lady can be most readily
distinguished from the Painted Lady by the two large, black-ringed
blue eyespots on the underside of the hindwing (Painted Ladies
instead have five small submarginal eyespots). V.
virginiensis' wing span varies from 53 to 67 mm (Opler, 1992);
the male forewing length ranges from 2.4 to 3.0 cm (mean = 2.7 cm).
Females are very slightly larger than males: forewing length ranges
from 2.4 to 3.1 cm (mean = 2.8 cm) (Opler and Krizek 1984). As do
V. atalanta and V. cardui, V. virginiensis has distinct
summer and winter forms. The summer form is larger and more brightly
colored, whereas the winter form is smaller and paler, with reduced
black markings (Opler and Krizek 1984). The number of broods varies
from two in the northern part of its range to three or four in the
southern U.S. Adults occur in every month in Mississippi and Florida,
but it is uncertain whether or not they are reproductive there during
the winter (Opler and Krizek 1984). Scott (1986) describes V.
virginiensis as being "somewhat migratory." A northward migration
was observed in Iowa and southern Ontario in spring
2001.
Whether or not adults can survive cold
winters is not clearly documented (Opler 1992). Because V.
virginiensis may not be able to overwinter in the northernmost
states (Opler and Krizek 1984), migrants may need to recolonize much
of the eastern U.S. each year (Opler 1992).
The
West Coast Lady, Vanessa annabella, unlike the previous three
species, is limited to western North America. It most commonly occurs
in a region between the West Coast and a north-south line through
eastern Colorado. It typically inhabits open areas, and occurs at
various levels in the mountains, from the Upper Sonoran to the
Canadian zones (Scott 1986). The larvae prefer to feed on plants of
the families Malvaceae (including hollyhock) and Urticaceae,
including the nettle species Urtica dioica and U.
urens) (Scott 1986). The dorsal side of the wings somewhat
resembles that of the Painted Lady, with two distinguishing
differences. The postmedian bar on the forewing of V.
annabella is orange, rather than white as for V. cardui,
and the tip of the forewing is more angled than that of the Painted
Lady.