Monochroa robusta
(Braun, 1921)
Monochroa robusta is a small gelechiid described by Annette Frances Braun in 1921. The is known from limited records in Ohio and South Carolina, with a wingspan of 11–12 mm. Larvae are leaf miners on Scirpus atrovirens, creating distinctive mines that begin as small transparent blotches and expand toward the leaf tip.
Pronunciation
How to pronounce Monochroa robusta: //ˌmɒnəˈkrəʊə roʊˈbʌstə//
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Identification
Distinguished from similar Monochroa by the combination of: dense purplish fuscous dusting obscuring ground color toward apex; oblique darker shade before middle of wing; yellowish costal streak at two-thirds position; and elongate black spot at end of . The specific mine on Scirpus atrovirens—beginning as small transparent blotch with underside opening, followed by linear green portion with parallel sides, then expanding semi-transparent section—provides additional diagnostic characters.
Appearance
Small with wingspan 11–12 mm. Forewings dull ocherous with dense purplish fuscous dusting, especially toward apex. Oblique darker shade crosses wing before middle, from to fold. Yellowish costal streak at two-thirds extends to middle of wing, beyond elongate black spot at end of . Dark line at base of cilia broken by four faint ocherous spots on costa; similar pale spots sometimes visible along termen. Hindwings fuscous.
Distribution
Recorded from Ohio and South Carolina, United States.
Diet
Larvae feed on Scirpus atrovirens (dark green bulrush).
Host Associations
- Scirpus atrovirens - larval plant
Life Cycle
Larvae mine leaves of plant. Mine begins as small transparent blotch with opening on underside of leaf, followed by linear green portion with nearly parallel sides where leaf substance is not eaten, then expands to larger semi-transparent section. Larva exits mine through circular hole in upperside of linear green portion to pupate. Larvae whitish with black .
Behavior
Larval leaf-mining creates distinctive mine architecture: initial blotch, linear non-feeding track, and expanded terminal section. occurs outside the mine.
Ecological Role
Larval herbivore on Scirpus atrovirens. Specific ecological role otherwise undocumented.
Similar Taxa
- Other Monochroa speciesWing pattern elements (purplish fuscous dusting , position and shape of oblique shade, costal streak characteristics, and spot ) distinguish M. robusta; plant association with Scirpus atrovirens provides additional separation where known.