Amorbia emigratella

Status

NATIVE

PORT INTERCEPT | DOMESTIC SURVEY

Taxonomy

Amorbia emigratella Busck (Tortricidae: Tortricinae: Sparganothini)

Common names: Mexican leafroller

NOTE: What is currently considered Amorbia emigratella likely represents three species (based on COI barcodes). Only specimens from Central Mexico and Hawaii are “true” A. emigratella. The other two entities might represent undescribed, cryptic species.

Adult Recognition

FWL: 8.0–11.0 mm (males); 11.5–12.0 mm (females)

Adults are pale yellow to brown and may be variably mottled with dark brown. Most individuals have a well defined costal spot that is a remnant of the median fascia. Abdominal segments 2–6 have a median dorsal pit and ocelli are absent. Males lack a forewing costal fold.

Male genitalia are characterized by a long, thin uncus; large, setose socii; and large, membranous valvae. Female genitalia are characterized by a sterigma with well-developed lateral lobes and a band-like signum on the wall of the corpus bursae.

Larval Morphology

The following account is summarized from MacKay (1962a)MacKay (1962a):
MacKay, M. R. 1962a. Larvae of the North American Tortricinae (Lepidoptera: Tortricidae). Canadian Entomologist, Supplement 28: 1-182. and Powell and Brown (2012)Powell and Brown (2012):
Powell, J. A., Brown, J. W. 2012. Tortricoidea, Tortricidae (part): Tortricinae (part): Sparganothini and Atteriini. In: Hodges, R. W. (ed.). The Moths of North America, fascicle 8.1. Wedge Entomological Research Foundation, Washington, D.C., 230 pp..

Mature larva approximately 25 mm in length; width of head 2.0–2.1 mm; head brownish yellow; prothoracic shield yellow with dark lateral band; body yellow-green to green; SV group on A1, 2, 7, 8, 9 numbering 3:3:3:2:2.

For more information on Amorbia larvae, including a more detailed account of chaetotaxy, please consult the fact sheet and keys on LepIntercept.

Similar Species

Few other North American tortricids are similar in size or appearance to Amorbia, and this is one of the few tortricid genera in which the adults lack ocelli. The three Amorbia species treated on this site can be separated by the combination of two characters: forewing color and number of median dorsal pits on the abdomen. Amorbia humerosana is gray, oftentimes with a brownish band on the inner margin and has a single median dorsal pit on the second abdominal segment. Both A. emigratella and A. cuneanum are yellow-orange or yellow-brown, but A. cuneanum has a median dorsal pit on segment 2 whereas A. emigratella has median dorsal pits on segments 2–6.

The lateral bands on the prothoracic shield can be used to distinguish late instar Amorbia larvae from those of many other tortricids. These characters can be used to separate late instar larvae of A. emigratella and Epiphyas postvittana from Hawaii, as both occur on similar host plants. Early instars lack the distinctive dark bands, and morphological identification of early instar larvae may be difficult or impossible.

Distribution

Amorbia emigratella is distributed across the southern United States and Central America. It has been accidentally introduced to all major Hawaiian Islands.

Biology

The following account is summarized from Phillips-Rodríguez and Powell (2007)Phillips-Rodríguez and Powell (2007):
Phillips-Rodríguez, E., Powell, J. A. 2007. Phylogenetic relationships, systematics, and biology of the species of Amorbia Clemens (Lepidoptera: Tortricidae: Sparganothini). Zootaxa. 1670: 1-109. and Powell and Brown (2012)Powell and Brown (2012):
Powell, J. A., Brown, J. W. 2012. Tortricoidea, Tortricidae (part): Tortricinae (part): Sparganothini and Atteriini. In: Hodges, R. W. (ed.). The Moths of North America, fascicle 8.1. Wedge Entomological Research Foundation, Washington, D.C., 230 pp..

Eggs are laid in masses of 65–120 eggs on the upper surface of leaves. Females cover the egg mass with a whitish coating. Larvae feed within a shelter constructed of webbed leaves or leaves webbed to fruit; they may also feed within flower heads or buds. Larvae complete 4-5 instars and pupation occurs in the larval shelter. Adults eclose in approximately 10 days.

Amorbia emigratella has been recorded from plants in more than 25 families, many of which include economically important crops or threatened/endangered species (in Hawaii).

Plant Associations

View full screen host table here

Links

Additional photos and distribution map in North America available at Moth Photographers Group.