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Journal of the Lepidopterists' Society 45(3), 1991, 204-208
THE LARVA OF OMMATOSTOLA LINTNERI (NOCTUIDAE: AMPHIPYRINAE)
Kenneth A. Neil
Agriculture Canada, Research Station, Kentville, Nova Scotia B4N 1J5, Canada
ABSTRACT. The last instar of Ommatostola lintneri Grote is described and illustrated.
Additional key words: larval morphology, host plant, hypopharyngeal complex, mouthpart structures, chaetotaxy.
Ommatostola lintneri Grote (Noctuidae: Amphipyrinae) is characteristically a species of coastal sand barrens. Although O. lintneri can be common in such habitats, its distribution is limited to an area from Nova Scotia, including Sable Island (Ferguson 1954), south to Long Island, New York, and New Jersey (Forbes 1954).
Little is known about the larval stages of O. lintneri. Forbes (1954) provided a very brief description of a larva he presumed to be O. lintneri, but indicated no adult association. Tietz (1972) listed Arenaria sp. (Caryophyllaceae) as a food plant, but gave no references.
To aid recent ecological investigations on Sable Island, I was asked to rear and identify several species of noctuid larvae from this locality. The most common species collected was a large, light sand colored larva which fed on the roots and stems of Arenaria sp., several centimeters below the surface of the sand. Delays in shipping the material from Sable Island to mainland Nova Scotia resulted in most of the larvae dying. A single specimen collected 1-6 July 1986 was reared on Arenaria sp. and an adult O. lintneri emerged 29 August 1986.
The following is a description of the last instar larva of O. lintneri based on the specimens collected on Sable Island, Nova Scotia. All illustrations were drawn to scale with the aid of a Wild stereomicroscope and ocular grid system. The terminology and abbreviations used follow those proposed by Godfrey (1972).
Ommatostola lintneri Grote
Morphological description (Figs. 1 and 2). Head width 2.9-4.3 mm (N = 4). Total body length 32.0-32.75 mm (N = 3). Body widest anteriorly, tapering posteriorly. Head semi-prognathous. Head and body smooth. Prolegs present on abdominal segments, (Ab) 3 to 6 poorly developed, all equal in size. Crochets uniordinal,8-12 per third abdominal proleg, 10-11 per fourth, 9-12 per fifth, 10-11 per sixth. All setae simple. Coloration of living material: Head (Fig. 3) reddish brown with black ocellar band; base of antennal socket black. Body (Figs. 1 and 2) light sand brown, dorsal area slightly darker, no lines or markings present. Cervical shield shining yellow brown, posterior margin slightly darker. Anal shield much lighter, also shining yellow brown. Pinacula light brown, dorsal pinacula slightly larger than lateral and ventral pinacula. Head yellowish brown, markings
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1
2
Figs. 1 and 2. Ommatostola lintneri Grote larva (x5) 1, lateral view. 2, dorsal view.
2.0 mm
0.5 mm
Spinneret
Stipolar Seta
Proximomedial Region
Proximolateral Region
0.5mm
1.0 mm
01mm
Figs. 3-7, 9. Ommatostola lintneri Grote larval structures: 3, head, frontal view. 4, hypopharyngeal complex, left lateral view. 5, labial palpus, lateral view. 6, left mandible, oral surface. 7, left mandible, outer surface. 9, anal shield, dorsal view.
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Fig. 8. Ommatostola lintneri Grote: dorsal and lateral chaetotaxy of prothoracic (Tl), mesothoracic (T2), and abdominal segments (Abl-3, Ab6-10).
as in living material. Body light creamy brown. Cervical shield pale yellowish brown. Spiracles dark yellow brown, peritremes black. Head (Fig. 3): Cervical indentation deep; adfrontal sutures terminating at epicranial suture: epicranial suture length about % height of frons; frons higher than width at base. Adfrontal setae (AF) 2 and posterior head setae (P) 1 above apex of frons; anterior head puncture (Aa) below a straight line projected through posterior head puncture (Pa) and anterior head setae (A) 3. P-l below straight line through P-2 and AF-1; Aa equidistant from A-3 to A-2, A-l to A-3 forming obtuse angle at A-2. Lateral head setae (L) above or below juncture of adfrontal sutures. Distance between ocelli (Oc)-3 to Oc-4 about half that between Oc-1 to Oc-2 or Oc-2 to Oc-3. Ends of postgenae well separated. Mouth parts: Hypopharyngeal complex (Fig. 4). Spinneret long, thin, and tapering anteriorly, about twice the length of Lps-1 and Lps-2 and Lp-2. Labial palpus (Fig. 5) with Lps-1 about 6 times the length of Lp-1, about 7 times the length of Lps-2 and twice the length of Lp-2; Lps-2 slightly longer than Lp-1. Stipular setae less than xh the length of Lps-1, about twice the length of Lp-1 and over twice the length of Lps-2. Distal and proximal regions continuous, distal region above spinneret bare, remainder covered by long coarse spines, spines becoming shorter and thinner proximally. Mandible (Figs. 6 and 7): Outer setae approximate; inner surface with 3 distinct ridges, outer surface with 5 distinct teeth, 1st to 3rd well developed and angular, 4th to 5th blunt. Thorax: Prothoracic segment (T-l) (Fig. 8). Shield smooth and weakly sclerotized, subdorsal body setae (SD)-l and SD-2 on separate setae; seta SD-1 and lateral body seta (L)-2 fine, hairlike, with a thickened annulus at base; major axis of prothoracic spiracle passing anterior to SD-1 and SD-2 and posterior of body setae (SV)-l and SV-2; spiracle oval, height more than twice its width. T-2 to T-3 (Fig. 8). SD-1 fine, hairlike, a thickened sclerotized annulus at base. Tarsal claws with basal angles acute. Metathoracic coxae well separated. Abdomen: Dorsal and lateral chaetotaxy as in Fig. 8. Ab-1 with 2 SV setae; Ab-2 to Ab-6 with 3 SV setae; SV-1 to SV-2 setal insertions well separated. Ab-7 to Ab-8 with 1 SV seta; Ab-9. SD-1 fine and hairlike, with a thickened annulus at base. Ab-10: anal shield as in Fig. 9, dorsal margin flat, posterior margin entire; subanal setae well separated.
Material examined: Fifteen specimens: Sable Island, Nova Scotia. All larvae collected 1-6 July 1986 by Ms. Zoe Lucas, reared on Arenaria sp., and determined by K. A. Neil. One adult male emerged 29 August 1986. All specimens have been deposited in the Nova Scotia Museum, Halifax, Nova Scotia, Canada.
Discussion
Subterranean feeding is a character shared by other Amphipyrine genera, such as Apamea (some species) and Crymodes. The larva of Ommatostola lintneri can be distinguished from these taxa by the light sandy brown coloration and external morphology, especially by the
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SD-2 seta, which is separated from the cervical shield. According to Crumb (1956), this character is shared only with Archanara oblonga (Grt), which is easily separated from Ommatostola lintneri by its coloration.
Acknowledgements
I thank Zoe Lucas for supplying me with the larvae of O. lintneri described here and Arthur Lightfoot of Agriculture Canada, Kentville, for photographing the plates.
Literature Cited
Crumb, S. E. 1956. The larvae of the Phalaenidae. U.S. Dept. Agr. Tech. Bull. 1135:
356 pp. Ferguson, D. C. 1954. The Lepidoptera of Nova Scotia (Macrolepidoptera). N.S. Mus.
Sci. Bull. 33:214 pp. Forbes, W. T. M. 1954. Lepidoptera of New York and neighboring states. Cornell
Univ. Agr. Expt. Sta. Mem. 329. 433 pp. Godfrey, G. L. 1972. A review and reclassification of larvae of the subfamily Hadeninae
(Lepidoptera, Noctuidae) of America north of Mexico. U.S. Dept. Agr. Tech. Bull.
1450:265 pp. Tietz, H. W. 1972. An index to the described life histories, early stages, and hosts of
the Macrolepidoptera of the continental United States and Canada. 2 vols. A. C.
Allyn, Allyn Museum of Entomology, Sarasota, Florida. 1041 pp.
Received for publication 23 January 1990; revised and accepted 6 July 1991.