Tischeriidae are very small moths, the larvae of which are upperside (rarely underside) blotch leaf miners. Until recently, all North American (and, in fact, world) species were placed in a single genus, Tischeria. That scheme was followed when the family was revised for North America by Braun (1972). A more recent analysis of the world fauna by Puplesis and Diškus (2003), however, recognized three genera, Tischeria, Coptotriche, and Astrotischeria (much information that is relevant to North America from this work is presented here).
Tischeriidae is well represented in the eastern USA. Illinois tischeriids can be superficially diagnosed into three groups, based on larval foodplant preference and corresponding coloration of the adult moth. In moths of the Fagaceae-feeding group, the forewing is clear dark yellow (sometimes with a small black patch at the tornus, but without blackish scaling scattered across the wing). In the Asteraceae-feeding group, the forewing is dark yellow and is overlaid with a diffuse scattering of blackish scales. And in the Rosaceae-feeding group, the entire moth is shining dark brownish gray.
These groups allow convenient categorization but do not align exactly with the monophyletic generic lineages argued by Puplesis and Diškus (2003), as Coptotriche contains both Fagaceae and Rosaceae feeders, and one Fagaceae feeder is placed in Tischeria. The Asteraceae feeders, however, do fall into the same genus, Astrotischeria, which does not contain Fagaceae or Rosaceae feeders. Because this site is introductory and identification-oriented in nature, the hostplant/coloration groups are maintained here, but generic assignments for all species are reflective of the Puplesis and Diškus (2003) analysis.
Leaf mines of Tischeriidae (Fig. 1) can be categorized into two general groups: marginal mines (Fig. 1A) occurring at the leaf margin, with the marginal part of the leaf curling upward and inward so that it partially covers the mine itself, and blade mines (Figs. 1B-C) occurring primarily on the flat surface of the leaf, although they often extend to the margin. Blade mines can be subcategorized into "irregular-blotch" (Fig. 1B) and "trumpet" (Fig. 1C) types. In general, within each tischeriid species, every larva will produce the same type of leaf mine. Among tischeriid species that occur in Illinois, all of the different types of mines occur within the Fagacae-feeding group; blade mines of the irregular-blotch type predominate in the Asteraceae-feeding group; and marginal mines and blade mines of the trumpet type occur in the Rosaceae-feeding group.
Figure 1. Leaf mines of Tischeriidae. A, marginal mine: Coptotriche crataegifoliae on hawthorn, Crataegus sp. (Rosaceae); B, irregular-blotch blade mine: Astrotischeria astericola on aster, Aster sp. (Asteraceae); C, trumpet blade mine: Coptotriche castaneaeella on shingle oak, Quercus imbricaria (Fagaceae).
Pupation in Tischeriidae occurs within the leaf mine, in a silken compartment termed a "nidus" (literally, "nest"). Overwintering occurs as a pupa in the oak- and composite-feeding species, as a larva in those species that feed on plants of the rose family. The pupal exuvium is protruded from the leaf mine at eclosion.
Adult Tischeriidae have a characteristic resting posture (Fig. 2A), in which the front end of the body is elevated above the substrate, with all legs being tucked under the body so that they are not visible (unlike adult gracillariinae Gracillariidae, in which the front end is elevated but the front and middle legs are held out to either side and thus are clearly visible). Adult tischeriids also have a distinctive fanlike tuft of ventrally-curved scales (Fig. 2B) projecting forward from the dorsal area of the head (in flown specimens, this tuft is sometimes worn away), and males of many species have long hairs projecting from some or all of the antennal flagellomeres (such setae are also seen in a few microlepidoptera groups outside Tischeriidae, e.g., the gelechioid genus Stathmopoda).
Figure 2. A, a typical adult tischeriid moth (Astrotischeria solidagonifoliella) at rest; B, head of Tischeria quercitella, showing the characteristic fanlike tuft of scales (seen in both genders) and the long antennal setae (seen only in males).