Gymnandrosoma trachycerus Forbes (Tortricidae: Olethreutinae: Grapholitini)
FWL: 8.3–9.6 mm (males); 8.0–11.2 mm (females)
Head dark brown, terminal segment of labial palpus white; thorax brown with a median transverse white and reddish-brown band; male without sex scale tuft on hind tibia; ground color of forewing brown, median fasciae darker, costal patch of median fascia white, reddish brown, or pale reddish brown, postmedian spot present, white; hindwing brown.
Male genitalia are characterized by uncus, socii absent; distally-swollen valvae with two to five short, stout spines on the lateral margin, and a slender, pistol-shaped phallus. Female genitalia are characterized by simple, narrow papillae anales; a scobinate patch near the junction of the corpus bursae and ductus bursae extending to nearly signa; ductus bursae without a spiral; and a pair of large, knife-like, opposed signa.
The larva was first described by Fennah (1942)Fennah (1942):
Fennah, R. G. 1942. The ldquo;Orange Mothrdquo; of Dominica, B.W.I. Tropical Agriculture. 19(4): 73-78.. The following account is summarized from Adamski and Brown (2001)Adamski and Brown (2001):
Adamski, D., Brown, J. W. 2001. Systematic revision of the Ecdytolopha group of genera (Lepidoptera: Tortricidae: Grapholitini) in the New World. Entomologica Scandinavica Supplement 58. 86 pp..
Mature larva 12–16 mm in length, spicules extremely fine, head and prothoracic shield pale yellow, SD1 slightly venteroanterad of spiracle on A8; SV group on A1, 2, 7, 8, 9 extremely variable: 3(2):3:3(2):2:2(1). Additional chaetotaxy details are available in Adamski and Brown (2001)Adamski and Brown (2001):
Adamski, D., Brown, J. W. 2001. Systematic revision of the Ecdytolopha group of genera (Lepidoptera: Tortricidae: Grapholitini) in the New World. Entomologica Scandinavica Supplement 58. 86 pp..
Gymnandrosoma trachycerus is very similar to several other species of Gymnandrosoma. It is best identified by the absence of certain characters present in other species. It lacks the white thoracic tuft of G. leucothorax, the notched antenna of males of G. aurantianum, and the complex male secondary features on the dorsum of the abdomen present in other species of Gymnandrosoma.
Gymandrosoma trachycerus is distributed throughout the Caribbean, with records from Hispaniola, Puerto Rico, the British Virgin Islands, Guadeloupe, Dominica, and Martinique.
The following account is summarized from Fennah (1942)Fennah (1942):
Fennah, R. G. 1942. The ldquo;Orange Mothrdquo; of Dominica, B.W.I. Tropical Agriculture. 19(4): 73-78..
In Dominica, larvae initially feed in the outer, fleshy fruit of Simarouba amara before boring into the seed to feed on the cotyledons. A single larva feeds in each fruit. Pupation usually occurs on the ground, but occasionally takes place inside the fruit. Citrus is also utilized in late May and early June as the first crop of oranges are developing. Adults have been collected year-round in the Caribbean and from coastal elevations all the way up to montane rainforests.
Authors: KA Austin, TM Gilligan, ME Epstein
Content last updated May 2025
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