Cosmopterix nitens is a moth

Moth

A moth is an insect closely related to the butterfly, both being of the order Lepidoptera. Moths form the majority of this order; there are thought to be 150,000 to 250,000 different species of moth , with thousands of species yet to be described...

 of the Cosmopterigidae

Cosmopterigidae

Cosmopterigidae is a family of insects in the Lepidoptera order. These are small moths with narrow wings whose tiny larvae feed internally on the leaves, seeds, stems, etc of their host plants. There are about 1,500 described species...

 family. It is known from the United States

United States

The United States of America is a federal constitutional republic comprising fifty states and a federal district...

, where it is found from coastal South Carolina

South Carolina

South Carolina is a state in the Deep South of the United States that borders Georgia to the south, North Carolina to the north, and the Atlantic Ocean to the east. Originally part of the Province of Carolina, the Province of South Carolina was one of the 13 colonies that declared independence...

 to south-western Texas

Texas

Texas is the second largest U.S. state by both area and population, and the largest state by area in the contiguous United States.The name, based on the Caddo word "Tejas" meaning "friends" or "allies", was applied by the Spanish to the Caddo themselves and to the region of their settlement in...

. It is also established in Michigan

Michigan

Michigan is a U.S. state located in the Great Lakes Region of the United States of America. The name Michigan is the French form of the Ojibwa word mishigamaa, meaning "large water" or "large lake"....

.

Adult

Male, female. Forewing length 3.8-4.5 mm. Head: frons shining ochreous-white, vertex, neck tufts and collar shining pale bronze brown with greenish gloss; labial palpus, first segment very short, white, second segment three-quarters of the length of third, grey with white longitudinal lines laterally and ventrally, third segment white, lined dark greyish brown laterally; scape dark bronze brown with a white anterior line, ventrally white, antenna dark bronze brown, beyond two-thirds a white ring of two segments, followed towards apex by fourteen dark bronze brown and five white, mixed greyish brown, segments at apex. Thorax and tegulae shining pale bronze brown with greenish gloss. Legs: dark grey, foreleg with a white line on tibia and tarsal segments one, two and five, segment three white in basal half, tibia of midleg with an oblique white dorsal line in basal half and a white apical ring, tarsal segments one and two with white apical rings, tibia of hindleg with oblique white basal and medial lines and a white apical ring, tarsal segments one, two and four with white apical rings, segment five dorsally white, spurs white dorsally, dark grey ventrally. Forewing shining bronze brown with a strong golden gloss, darker bronze brown in female, an inwardly oblique broad silver to pale golden metallic fascia at one-quarter, widening towards dorsum, but not reaching it, a pale yellow transverse fascia beyond the middle, narrowing towards dorsum, bordered at the inner edge by a tubercular silver to pale golden metallic fascia, perpendicular at dorsum and not reaching costa, bordered at the outer edge by a broad, slightly outward oblique similarly coloured fascia, widest on dorsum, both fasciae with some pale reddish reflection, in the middle of the transverse fascia a broad blackish brown streak with strong reddish gloss, the inner fascia with some irregular blackish brown lining on the outside, the outer fascia lined blackish brown on the inside, outer fascia costally edged by a white costal streak, apical line as a broad silver to pale golden metallic streak from the middle of the apical area and ending just before apex, cilia bronze brown around apex, paler towards base, hindwing pale brownish grey, cilia greyish brown. Underside: forewing shining greyish brown, the apical line indistinctly visible, hindwing greyish brown. Abdomen shining brown, segments banded paler posteriorly, laterally shining grey with greenish reflection, ventrally yellowish white, anal tuft dorsally brown, ventrally yellowish white.

Larva

Head black, body yellowish orange to brownish with a red dorsal and single lateral broken lines.

Biology

The larvae feed on Phragmites australis. They mine

Leaf miner

Leaf miner is a term used to describe the larvae of many different species of insect which live in and eat the leaf tissue of plants. The vast majority of leaf-mining insects are moths , sawflies and flies , though some beetles and wasps also exhibit this behavior.Like Woodboring beetles, leaf...

 the leaves of their host plant. The mine has the form of a gallery ranging in length from three to seven cm. The frass

Frass

Frass is the fine powdery material phytophagous insects pass as waste after digesting plant parts. It causes plants to excrete chitinase due to high chitin levels, it is a natural bloom stimulant, and has high nutrient levels. Frass is known to have abundant amoeba, beneficial bacteria, and fungi...

is piled at basal end of the mine and expelled from an opening at that end. The larva moves along the mine when disturbed. It hibernates in its cocoon inside the mine. Adults fly from March and April until October. It is multivoltine at least in the south, but probably univoltine in Michigan.