Noctuidae - Agaristinae

 

Male

Female

Color Photograph: Greg Dwyer, Creative Commons Attribution ShareAlike 2.5

 

Alypia octomaculata (Fabricius)

Sesia octomaculata Fabricius, 1775, Systema Entomolgiae, p. 830.

Phalaena Noctua albomaculata Stoll, 1782, Uitlandsche Kapllen, 4: 106, pl. 345, fig. C.

Zygaena bimaculata Gmelin, [1790], in Linnaeus, Systema Naturae, edition 13, 1(5): 2398.

Alypia octomaculalis Hübner, 1818, Zuträge Sammlung Exotischer Schmetterlinge, 1: 22.

Alypia quadriguttalis Hübner, 1818, Zuträge Sammlung Exotischer Schmetterlinge, 1: 22.

Alypia matuta H. Edwards, 1883, Papilio, 3: 33. NEW SYNONOMY

Diagnosis: Alypia octomaculata is one of the most familiar noctuids in the eastern United States and southeastern Canada. The forewing is black with two large, round, yellow-white patches, the more basal patch located in the middle of the anterior half of the median area, and the second patch placed just past the position of the postmedial line. The forewing also contains some metallic blue lines, although these lines are never distinctive and are seldom visible unless the light reflects off the wing in just the right way. At the base of the forewing this blue scaling radiates out from the base along the radial and anal veins to the top and bottom the more basal of the yellow forewing patches. The postmedial line is represented by a very vague blue line and occassionally a few blue scales are present between the outer yellow patch and the apex of the wing. The ventral forewing recapitulates the dorsal side except that the inner yellow patch is larger and the lower margin of the patch is confluent with the inner margin. The blue scaling of the dorsal surface is absent from the ventral side. The hindwing is black with a basal white patch separated by a black bar through the discal dot from an outer, smaller white patch. The basal white patch is isolated by a black band from the inner margin in females, but in males this black band is typically reduced to a fine black streak on the second anal vein, the white reaching the inner margin. The ventral surface of the hindwing mirrors the dorsal surface. A white line is present along the dorsal surface of the male abdomen, although the white is most apparent on abdominal segments one and seven. In many specimens it appears as if there are only white dots on these two segments. These white markings are absent in females. Wing length: (males New York) mean = 13.79 mm, standard deviation = 0.84 mm, n = 10; (females New York) mean = 15.06 mm, standard deviation = 0.81 mm, n = 10; (males Colorado) mean = 14.80 mm, standard deviation = 0.68 mm, n = 10.

Distribution: Alypia octomaculata is a wide-spread and common species in the eastern two-thirds of the United States and southeastern Canada. In the east the species occurs as far north as southern Maine, southern Quebec and southern Ontario. The dividing line between this species and langtoni appears to follow closely the distributions of their respective foodplants (Epilobium for langtoni and grape and virginia creeper for octomaculata). This species extends westward in the north as far as eastern North Dakota and southward from there to Colorado, New Mexico, and most of Texas except the southern tip of the state. Alypia octomaculata occurs throughout most of the rest of the eastern United States except for Florida. The distribution of octomaculata in the southeastern United States needs to be examined in more detail. Collections are scanty from this part of the country and in South Carolina and Georgia the relationship between octomaculata has not been satisfactorily resolved. The species is slightly sexually dimorphic. The male has a series of white or yellow-white spots on the dorsum of the abdomen. No white spots are found in the female. The white spots in the female hindwing are almost always smaller than in the males. In a few females the outer white spot is very small, almost disappearing in some specimens. The basal white patch in the male hindwing almost always has a black streak on the second anal vein, but ocassional specimens have this streak poorly developed or almost absent. The conspicuousness of the white or yellow-white markings on the dorsum of the male abdomen is also variable. The markings may be reduced to white spots on the first and seventh abdominal segments, or white scales may be found more generally on the other segments as well. Geographically specimens from Colorado, New Mexico, and the central Great Plains tend to have the white basal patches in the female hindwing as large and well developed as in the males. The white patch in the male hindwing lacks a black streak on the second anal vein usually found in the eastern populations. The Colorado-New Mexico population is slightly larger than their more easterly cousins. Finally the yellow-white markings on the male abdomen are, on average, more extensive and most commonly forming a continuous yellow-white line from the second to the seventh abdominal segments. A continous yellow-white line is almost never found in the eastern populations of octomaculata. If a subspecies concept is employed the name matuta is available for this population. The problematical populations of octomaculata or wittfeldii from coastal Georgia and South Carolina are discussed under wittfeldii.

Adults fly from April to July, appearing somewhat earlier in the more southerly parts of the species' range.

Identification Quality: Excellent

Larva: The larva is very striking. The dorsal three-fourths (down to seta L2) of each abdominal segment are white with approximately eight regular black bands circling each segment. The ventral fourth of the abdomen is black. The setae on both the abdominal and thoracic segments are located on prominent black pinacula. An elongate-ovate patch encloses the spiracle on each abdominal segment and stretches from seta SD1 dorsally to L2 ventrally. An orange patch also surrounds seta L3 on each of the proleg bearing abdominal segments. A large dorsal orange patch containing the D1 and D2 setae is found on abdominal segment 8 and oblong patches behind the D1 setae on abdominal segments one through three. A prominent white patch stretches from the L1 seta of segment 7 to the L2 seta of segment 8. The prothoracic shield is orange with very large black spots surrounding the seta contained in it. The head is off-white with black spots surrounding each of the setae.

The larva might be confused with either langtoni, disparata, or maccullochii. The larva of wittfeldii is unknown. The foodplants of langtoni and octomaculata appear to be mutually exclusive; langtoni on species of Epilobium (Onagaraceae) and octomaculata on species of the Vitaceae. The abdominal segments of octomaculata are primarily white, with thin, distinct vertical (dorsal to ventral) black lines. The black-brown lines of langtoni are much more irregular and not distinctly vertical. The dorsal surface of octomaculata is primarily white and crossed by the thin black-brown lines found on the lateral sides of the segments. The dorsal surface of langtoni has two large black-brown patches. The following differences are present between octomaculata and disparata. First the spiracular regions of abdominal segments one through seven lack the orange patches of both octomaculata and langtoni, although orange may be found in the ventral and lower lateral regions. A strong black band runs vertically through the D1, SD1, and spiracles on the mesothorax and metathorax and abomdinal segments 1 through 5. This dark line is much stronger than the other vertically running lines. This line, if present, in octomaculata, is not stronger than the other vertical lines. Alypia octomaculata does not appear to be sympatric with maccullochii anywhere. The species apparently utilize different foodplants (i.e. Epilobium in maccullochii versus species of the Vitaceae for octomaculata). The larva of maccullochii lacks the prominent white patch found on the lateral side of abdominal segments seven and eight found in octomaculata. The larva appear in late May and June, pupating in a weak earthern cocoon in August and overwintering as a pupa, the adult emerging in late spring of the following year.

Foodplants: Crumb (1956) lists grape [Vitis spp.] and Virigina Creeper [Parthenocissus quinquefolia], both members of the Vitaceae. Forbes (1960) also lists Japanese Ivy (Parthenocissus tricuspidae as a foodplant. Records on rose and barberry are probably incorrect or accidentals. Riley (1870) records the eight-spotted forester as a pest of commercial grape (although not stipulating which species). I have seen no recent records of the species being a serious pest of commercial grapes, either wine or table grapes. The adult and the larva and sometimes fairly abundant and are commonly seen around the ivy covering buildings such as the halls on college campuses.

 
Alypia octomaculata

 

Alypia octomaculata can be confused with three species found on the periphery of its distribution; langtoni, wittfeldii, and disparata. Alypia langtoni is a more northern species than octomaculata. The female of langtoni is easily separated from that of octomaculata by the presence of a single yellow patch in the hindwing. The female hindwing of octomaculata is basically the same as that of the male with a basal white patch separated by a black bridge from a smaller white patch in the outer half of the discal cell. The male of langtoni, however, can be difficult to distinguish from a male octomaculata. The following characters, however, will almost always separate the two species. The best character separating males of the two species is the presence of white rings around each of the basal antennal segments in langtoni and their absence in octomaculata. The character can sometimes be seen with the naked eye, but it is best to examine specimens under the microscope or with a hand lens. The ventral surface of the basal antennal segments of octomaculata may have white scales, but these white scales do not form white rings and are not visible on the dorsal surface of the antenna. The distal end of the second palpal segment has a ring of yellow hair-like scales in octomaculata. Yellow hair-like scales are present in langtoni, but are much less common and usually restricted to the inner side of the second and third segments. Both langtoni and octomaculata have a rows of yellow scales on the outer margins of the front of the head. This row of yellow hair-like scales is not as strong in langtoni as in octomaculata. In langtoni this row of yellow hair-like scales is two to three times longer than wide and the lower end of the row ends near the top of the frontal process. This row is four or five times longer than wide in octomaculata and the lower end usually curves slightly around the lower end of the frontal process. Wing maculation characters for separating males of langtoni and octomaculata are useful but less reliable. The two yellow forewing patches are usually (but not always) smaller in langtoni than octomaculata. The basal white hindwing patch of langtoni is typically smaller and more heavily streaked with black than it is in octomaculata.

Alypia disparata occurs in central and southern Texas on the southern border of the range of octomaculata. The elongate, pointed forewing of disparata should almost always separate this species from octomaculata. There are a number of other distinctive features that may be used to identify disparata. The palpi of disparata are completely brown-black. The palpi of octomaculata (as well as langtoni and wittfeldii) have a large patch of yellow scales on the lower third of the first palpal segment as well as a ring of yellow scales around the apex of the second segment. A patch of yellow scales is present on the anterior margin of the thorax formed by the yellow interior edges of the two patagia. This yellow patch in absent in disparata. The dorsal surface of the abdomen of octomaculata almost always has some white scaling, usually as a line running along the dorsal surface and ending is a white dot on the eighth tergum. The white scaling is variable in development in octomaculata, but is nearly always present. White scaling is always absent in disparata.

The differences and relationship between octomaculata and wittfeldii are discussed under wittfeldii.

Similar Species

Alypia langtoni

Alypia wittfieldii

Alypia disparata