Microlepidoptera comprise an informal grade of moth taxa. Essentially it includes a paraphyletic assemblage, or all the primitive higher taxa and the lower or more ancestral superfamilies of the Ditrysian Lepidoptera (numbers 1-3863 in the Hodges et al., 1983, Check List of the Lepidoptera of North America). There are about 1,675 species of these moths known in California, of which about 20% are recognized as undescribed.
Owing to the small size of most species and the difficulty of handling specimens, Microlepidoptera are generally ignored by collectors, even most lepidopterists. As a result, they have attracted few students, and taxonomic studies have lagged behind those of larger moths (`Macrolepidoptera') and butterflies. In families with the smallest adults, an estimated 50% to 90% of species that have been collected in California are undescribed, i.e., have no names. Moreover, there are no contemporary specialists for several families, so it is difficult to ascertain which are the described species and identify them.
Although not a monophyletic lineage, Microlepidoptera provide a useful group for comparative biological studies. Larvae of nearly all are concealed feeders: leaf miners; borers in roots, stems, seeds; cause plant galls; or create shelters using silk to draw togther leaves or other feeding substrates. The vast majority are host plant specialists, often depending upon plants of one genus or a few closely related genera, or even one species in most leaf miners and gall formers. By contrast, most macrolepidopterous moth larvae are external feeders that do not make shelters, and most are generalists, feeding on a variety of plants, often low-growing herbs, grasses, or trees and shrubs, varying with the species. Thus Microlepidoptera are much more valuable as indicators of the richness and health of a plant community, particularly in disturbed places, because they require smaller patches of habitat to survive than do butterlies or large moths.
The "Check List of the Insects of Frances Simes Hastings Natural History Reservation," which was compiled in the 1940's by Jean Linsdale and others, has only a few Microlepidoptera, 3 species names and 4 additional generic names in 5 families. The list evidently was based on the collection at Hastings, which now is housed at The Oakland Museum. I reorganized the collection in March 1998 and found ca. 600 specimens of Microlepidoptera, sorted them to taxa, identified all that I could without dissections, and affixed ID labels to the packets. Some of these had been identified by L. M. Martin and J. A. Comstock in 1940-1950 (most of them in error), and others by me in 1957-58, when I visted Hastings with Don Linsdale, who was my cubicle mate in graduate school. Some of the Tortricidae were transferred to the collection at Berkeley at that time, and the data have been published (Powell 1964, 1980). The Hastings list lacks most of the early identifications. Additions were penned into the list in other Lepidoptera families but not for the Microlepidoptera.
I differentiated about 70 species in the collection at the Oakland Museum, of which many species of Gelechioidea will require dissections to provide generic placement. I did not record the collection dates. These species are desigated in the following list by H.
I collected at Hastings with Don Linsdale in March 1957 and May 1958, with Jim Kruse on May 30, 1997, and on 6 dates in March, May, June 1998 and June 1999, and I recorded a few species of Microlepidoptera from larval collections made in March and May. During most of these visits, nights were cold and not very productive for Microlepidoptera attracted to blacklights. Species identified from these collections and a few earlier dates for which I found specimens in the Essig Museum at Berkeley are designated by month-year on the following list (e.g., V.97). There may be additional species in the Essig Museum from which the data have not been retrieved. My rearing lot numbers are given for species recorded by leaf mines, galls, or adults reared from field collected larvae. The lot designations are based on the collection date (e.g. 58E3 = 1958, May, 3rd collection).
Based on the inventory at Big Creek Reserve and the similar numbers of butterflies known at the two reserves, I would expect Hastings to produce 300+ species of Microlepidoptera. The present list records about 130 species including unplaced species in Blastobasidae, Coleophoridae, and Gelechiidae.View Species List ➜