Epiblema otiosana (Clemens) (Tortricidae: Olethreutinae: Eucosmini)
Common name: bidens borer moth
Synonyms: inclinana (Paedisca)
FWL: 5.0–9.5 mm
Head and thorax brown to dark brown, thorax with conspicuous dorsal tuft. Ground color of forewing brown; creamy white interfascial spot variably developed, irregular in shape, ocellus pale brown-orange to white with two or three small black dots; costal strigulae weakly contrasting except towards apex where they are separated by distinct red-orange scales; males without costal fold; hindwing dark brown.
Male genitalia are characterized by a poorly developed uncus; broad, well-developed socii; the dorsal margin of valvae only slightly concave; and the cucullus relatively small for the genus. Female genitalia have the sterigma nearly quadrate and corpus bursae with two signa.
The following account is summarized from Decker (1932)Decker (1932):
Decker, G.C. 1932. Biology of the Bidens borer, Epiblema otiosana Clemens (Lepidoptera: Olethreutidae). Journal of the New York Entomological Society. 40. 503-509. and MacKay (1959)MacKay (1959):
MacKay, M. R. 1959. Larvae of the North American Olethreutidae (Lepidoptera). Canadian Entomologist, Supplement 10: 1-338..
Mature larvae are approximately 12 mm in length, width of head 1.0–1.3 mm. Head brown; prothoracic shield brown with darker speckling; legs and anal shield light brown; body yellowish white with large, nearly black pinacula; anal fork absent. SV group on A1, 2, 7, 8, 9 usually 3:3:2:2:1.
A complete description of larval chaetotaxy is given in MacKay (1959)MacKay (1959):
MacKay, M. R. 1959. Larvae of the North American Olethreutidae (Lepidoptera). Canadian Entomologist, Supplement 10: 1-338..
The pupa is approximately 10–12 mm in length and light brown to dark brown in color.
Epiblema otiosana is very similar to several other species, including Eucosma parmatana and other species of Epiblema. Examination of the genitalia may be necessary. Eucosma parmatana can be easily separated from males of Epiblema by the well-developed ventral angle of the cucullus, which is absent in Epiblema. The shape of the white interfascial spot may be enough to separate E. otiosana from congeners, but this mark is variable and not always developed. The genitalia of both sexes are most similar to E. dorsisuffusana, but this species has much more extensive white scaling along the inner margin and around the ocellus.
Epiblema otiosana is broadly distributed in eastern North America wherever its host plant grows, from North Dakota to New Brunswick, south to Florida and eastern Texas.
The following account is summarized from Decker (1932)Decker (1932):
Decker, G.C. 1932. Biology of the Bidens borer, Epiblema otiosana Clemens (Lepidoptera: Olethreutidae). Journal of the New York Entomological Society. 40. 503-509..
Eggs are laid singly or in groups of two to three on the leaves of the host plant, often on the lower surface. Eggs hatch in approximately 4 to 15 days, depending on temperature. In Iowa, eggs are laid from late May to early July, with the first generation of larvae hatching and feeding in mid June to early July. Young larvae feed on leaf buds or burrow into and mine young leaves. As the larva feeds and grows, it migrates from the buds or leaves to the main stem by the second or third instar, leaving wilting and dying tissue behind. The larva will continue feeding in the main stem until pupation occurs in late July and into early August after five to seven instars, with the usual number being five. Total development time from hatching to pupation averages about four weeks.
Pupation occurs in the stem of the host plant. Mature larvae will cut a small exit hole through which the adults will emerge after eclosion, which occurs throughout August. A second generation occurs immediately after with larvae ceasing feeding activity in September and overwintering in the stems of the host plant. Pupation occurs the following spring with adults eclosing in May and June.
Larvae feed primarily on beggarticks (Bidens spp.) but have been recorded from a few other species as well.
View full screen host table here
Authors: KA Austin, TM Gilligan, ME Epstein
Content last updated May 2025
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