Mimallonidae Burmeister (mimallonids), sometimes known as "sack-bearer" moths for the larval case-building behavior, are a family of Lepidoptera containing over 300 named species in 43 genera.[1][2][3] These moths are found only in the New World, with most taxa occurring in the Neotropics.[4] Adult moths are externally similar to those belonging to some of the other Macroheterocera families Bombycoidea and Drepanoidea, and thus have been variously treated as belonging to either one of these or other superfamilies.[4][5]
Mimallonids are restricted to the New World, and are distributed in North America, Central America, South America, and the Caribbean (Cuba and The Bahamas).[2] The vast majority of genera and species are found in the tropical regions of the New World, with only five described species from the United States.[6][2]
Not much has been published on the natural history of adult Mimallonidae, though most species are thought to be nocturnal.[4] At least three species have diurnal males.[7][8] Young caterpillars live inside of folded leaves or beneath silken networks, and build portable or semi-portable cases out of silk, frass, and plant material as they grow.[4] The cases are open on either end and vary from irregular in structure to spindle-shaped.[4] The openings of the cases can be blocked by the head and/or the flattened anal plate of the last segment of the body.[4] The sack-like case-making behavior of the caterpillars have earned them the common name "sack-bearers".[9]
Mimallonidae larvae feed on several families of plants, including (but not limited to): Anacardiaceae, Clusiaceae, Combretaceae, Fagaceae, Melastomataceae, Myrtaceae and Rubiaceae.[4][10] Research at the Area de Conservación, Guanacaste, Costa Rica has resulted in the rearing of many species of Mimallonidae, including some from several additional families of plants.[10]
The current consensus, especially in works based on phylogenetic results, consider Mimallonidae to be the sole family of Mimallonoidea.[5][11][12] Other phylogenetic studies of all major Lepidoptera lineages support the placement of Mimallonidae as sister to all Macroheterocera, but within the broader clade Obtectomera.[11][12] This phylogenetic placement means that mimallonid moths are not more closely related to any one family of Lepidoptera, but are equally related (share a common ancestor with) all members of the extremely diverse clade Macroheterocera.[11] Morphological features, particularly of the larvae, support the uniqueness of this family and distinctness from Macroheterocera.[4][9]
The systematic relationships with Mimallonidae have been subject to two revisions, resulting in two different classification schemes. William Schaus revised the family and named most of the genera, he then separated the genera into two subfamilies: Lacosominae and Mimalloninae.[13] These subfamilies were based on the presence (Lacosominae) or the absence (Mimalloninae) of the frenulum.[13] It was later realized that this character varies within genera, and thus was deemed a sympleisiomorphy.[4][14] Using molecular phylogenetics, specifically with the technique of anchored hybrid enrichment, the family was reorganized based on the recognition and naming of robustly supported clades, which were further strengthened with morphological apomorphies.[1][5] The clades which were robustly supported across all analyses were assigned subfamily status, resulting in recognition of seven subfamilies in Mimallonidae.[1][5] Using both molecular and morphological phylogenetics, all 42 genera (including some newly described ones) were assigned to the named clades.[1][2][5] The 300+ species of the family, too, have been formally classified according to their phylogenetic arrangement.[2]