Moths of North Carolina
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5 NC Records

Samea multiplicalis (Guenée, 1854) - Salvinia Stem-borer Moth

Samea multiplicalis
Taxonomy
Superfamily: Pyraloidea Family: CrambidaeSubfamily: PyraustinaeTribe: SpilomeliniP3 Number: 80a1099 MONA Number: 5151.00
Identification
Field Guide Descriptions: Online Resources: MPG, BugGuide, iNaturalist, Google, BAMONA, GBIF, BOLDTechnical Description, Immature Stages: Center et al. (2002)                                                                                 
Adult Markings: This species is very similar to S. castellalis, with the ground color of the forewing being overlain with an array of nearly translucent, whitish patches. The patches are roughly arrayed in three bands, with the whitish patches either thinly margined basally and apically with black, or divided by a black line. The basal band has three or four very small whitish patches, while the median band has a squarish white patch below the costa that is followed by two or three additional patches inwardly. The subterminal band consists of a cluster of small white patches. The costa has four blackish spots in the subapical area, while the fringe is white with a row of evenly spaced blackish spots at the base. There is often a matching group of blackish spots along the termen. The hindwing has a large translucent area on the basal two-thirds, while the apical third of the wing is brown to reddish-brown. Wavy antemedial and postmedial lines are present within the basal two-third of the wing.

Samea castellalis is very similar to S. multiplicalis. It can be distinguished by the darkened area of the fringe midway along the margin (S. multiplicalis has a row of unfused, equally spaced spots along the termen), and by the pale and white spots in the forewing median area near the inner margin that are separated by a black line. In S. castellalis the spots are of equal size, while in S. multiplicalis, the more basal spot is noticeably larger than the other (see the S. castellalis account for details).
Wingspan: 16-20 mm (Beadle and Leckie, 2018).
Adult ID Requirements: Identifiable from good quality photos of unworn specimens.
Immatures and Development: The larvae feed on several species of aquatic plants, including Water Hyacinth, Water Lettuce, Carolina Mosquito-fern and Giant Salvinia. The following is based on the life cycle as described by Center et al. (2002). Females each lay about 150 eggs and typically place them singly on the host plants, with hatching occurring in about 4 days. The feeding mode varies depending on the host plant. Larvae may feed within a refugium made of silk and hairs of the host plant that is attached to the external leaf surface, or from galleries within the leaves (Water Lettuce). The refugium, when present, consists of a silk canopy stretched across the surface of the leaf and is periodically enlarged to reach fresh leaf material. The larger larvae feed on the buds of the plants, which often kills the growing apex. The larvae will also eat maturing Water Lettuce fruits and enclosed seeds. There are 5–7 instars, which require 15–16 days for development at 28 C when feeding on Water Lettuce or Salvinia, and 21–35 days at 26 C when feeding on Salvinia (Center et al., 2002).

Pupation occurs within a silken cocoon that is usually formed within the spongy portion of a Water Lettuce leaf, or among old leaves of Salvinia. The pupal stage last from 4-9 days and the time from egg to adult is 25-42 days in the laboratory. Center et al. (2002) noted that populations fluctuate markedly and can become exceedingly high during population peaks. Under certain conditions there can be massive destruction of Water Lettuce mats, but they often recover as the growing season progresses.
Distribution in North Carolina
Distribution: Samea multiplicalis was originally described from Brazil and is widely distributed throughout warmer regions of North and South America. In the U.S., this species is primarily found in the southeastern Coastal Plain from North Carolina southward to southern Florida, and westward to eastern and central Texas. Isolated records are also known from areas farther north, including Oklahoma, northern Virginia, Rhode Island, Ohio, New York and Ontario. As of 2023, we have only four site records for this species, with three in the Coastal Plain and one in the Piedmont.
County Map: Clicking on a county returns the records for the species in that county.
Flight Dates:
 High Mountains (HM) ≥ 4,000 ft.
 Low Mountains (LM) < 4,000 ft.
 Piedmont (Pd)
 Coastal Plain (CP)

Click on graph to enlarge
Flight Comments: Local populations are multivoltine in Florida, Louisiana, and Texas, with the adults flying year-round or nearly so. Populations farther north have relatively short flight periods. As of 2023, our records range from early-August through mid-October, with populations appearing to be univoltine.
Habitats and Life History
Habitats: Local populations are generally centered around sluggish aquatic habitats such as swamps, permanent ponds, lakes, marshes and canals that support aquatic vegetation.
Larval Host Plants: The larvae are moderately polyphagous and feed on aquatic plants (Knopf and Habeck, 1976; Center et al., 2002; Heppner, 2007; Robinson et al., 2010; Tewari and Johnson, 2011; Beadle and Leckie, 2018). The reported hosts include, Carolina Mosquito-fern (Azolla caroliniana), Feathered Mosquito-fern (A. pinnata), Water Lettuce (Pistia stratiotes), Pickerelweed (Pontederia cordata), Water Spangles (Salvinia minima), Giant Salvinia (S. molesta) and a duckweed (Spirodela sp.). Knopf and Habeck (1976) noted that the moths on rare occasion will also use Common Water-hyacinth (Oshuna crassipes). - View
Observation Methods: The adults are attracted to lights and the larvae can be found on floating aquatic plants.
Wikipedia
See also Habitat Account for General Herbaceous Ponds
Status in North Carolina
Natural Heritage Program Status:
Natural Heritage Program Ranks: GNR [S2S4]
State Protection: Has no legal protection, although permits are required to collect it on state parks and other public lands.
Comments: This species reaches the northern limit of its main range in North Carolina and is uncommon within the state. We need additional information on host use, distribution and abundance before we can accurately assess its conservation status.

 Photo Gallery for Samea multiplicalis - Salvinia Stem-borer Moth

Photos: 1

Recorded by: David L. Heavner on 2021-08-16
Chatham Co.
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