Species Malacosoma americana - Eastern Tent Caterpillar Moth - Hodges#7701

7701

Eastern Tent Caterpillar (larva)

Malacosoma americana (Fabricius, 1793)

Bombyx americana Fabricius, 1793

The gender of Malacosoma is neuter, so adjectivic species names ending -a are considered wrong spellings.(1) Following the Code of Zoological Nomenclature, the correct combination would be Malacosoma americanum (Fabricius, 1793).

The 2018 Canada & AK Checklist uses original spelling for species-level names following the practice "... by most lepidopterists in leading catalogues and checklists, as discussed by Sommerer (2002) and formally adopted by the Societas Europaea Lepidopterologica."(2)(3) For further justification see Nieukerken et al. (2019).(4) - Steve Nanz - 10/29/2019

one of 6 species in this genus in North America common

wingspan 22-44 mm (5)

Caterpillar length to 57 mm (2¼ in) (6)

Adult: body and wings warm fawn brown; forewing with white AM and PM lines; median area sometimes white (5)

wings of male are darker and more brownish; wings of female are paler and more yellowish

Larva: distinguished by a solid cream/white line along the dorsum (middle of the back). Sides of the body are marked with blue, black, orange and white. Dark face.

Eastern and central US to the Rockies (6) and Canada from Nova Scotia to Alberta

Tents appear in early spring, and caterpillars are seen until early summer (7).

On Block Island, RI, adults fly throughout June and July, peaking in abundance in early July.(8)

larvae feed on leaves of many trees and shrubs but particularly members of the rose family such as apple, cherry, and crabapple (5)

Female deposits egg mass on twig where it overwinters (6).

Larvae emerge in spring and begin building their tent which they continue to expand as they grow.

Fully grown caterpillars eventually disperse and find a place to pupate.

1.group of larvae 2.Cocoon 3.Pupa 4.Adult female 5.Adult male

one generation per year; overwinters as an egg

A good overview of larval habits (shelter building, feeding, thermoregulation, anti-predator defense, trail making and recruitment) appears on this page by Terrence Fitzgerald.

Most of the hosts of this caterpillar have little value so it doesn't contribute to economic losses.(9)

A parasitoid that attacks this moth is Itoplectis conquisitor. This ichneumon is attracted by the scents from flowering plants in orchards, but only when nectar is available.(10)

Telemonus clisiocampanae, a wasp in the Scelionidae family, parasitizes the eggs(9)

Malacosoma disstria forewing has dark AM and PM lines. The median area is often darker than the remainder of the forewing.

Malacosoma californicum is slightly smaller but otherwise similar and probably indistinguishable from M. americanum in areas where their ranges overlap.

compare photos of all 3 species at CBIF

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Larva of Forest Tent Caterpillar (Malacosoma disstria) has a broken dorsal line forming keyhole or footprint shapes along its back, and generally more blue on its body, including the face. Larvae form silken mats where they congregate, not tents.

Fabricius, 1793. Ent. Syst. 3(1): 433

Stehr, F.W. & E.F. Cook 1968. A revision of the genus Malacosoma Hübner in North America (Lepidoptera: Lasiocampidae): systematics, biology. immatures, and parasites. Bulletin of the United States National Museum. 276: 1-321. (1)

Wagner, p.226 (11)

Moth Photographers Group

distribution in Canada list of provinces (CBIF)

FCPS.edu