Thysania agrippina is a species of moth in the family Erebidaefirst described by Pieter Cramer in 1776. The most commonly accepted English name is the white witch. Other common names include the ghost moth, great grey witch and great owlet moth. Thysania agrippina is of interest as a competitor for title of "largest insect". This may be true by the measure of wingspan—a Brazilian specimen with a wingspan of almost appears to hold the record. The Atlas moth and Hercules moth, however, have greater wing areas. The white witch occurs from Uruguay to Mexico, and appears as a stray as far north as Texas in the U.S. Collection dates shows no discernible pattern with respect to location or season.
History
One story of the derivation of the common name: early naturalists collected specimens of birds and bats with shotguns. An enormous darting flyer high in the canopy was a tempting target. Firing a cloud of pellets at a white witch moth did not necessarily bring it down, however, because the body is small relative to the wing area. The moth would sail along, an unkillable witch. This moth is of historical interest as the subject of a well-known painting by the artistMaria Sibylla Merian. Merian was an insightful naturalist who advanced the 18th-century understanding of insect life cycles; however, her depiction of the white witch life cycle is inconsistent with the known biology. as Thysania agrippina is a sphingid, probably Pachylia syces.
Given the enormous geographic range of the adult, and observations that date back 300 years, it is striking that the immature life stages of this species have never been documented. Long migratory flight is likely, given that the close relatives Thysania zenobia and Ascalapha odorata are known for flights that reach far north of the host plant distributions. Based on the larval host plants recorded for the owl moth and black witch, the larval host plants for the white witch are probably also woody members of Fabaceae, possibly Senna and/or Cassia. White Witch Watch is a project led by the lepidopterist David L. Wagner at the University of Connecticut, seeking to identify the immature stages of the white witch. A key strategy: to obtain a gravid female and attempt rearing on likely hosts. The participants maintain a website, and an active citizenscience project on iNaturalist.
Taxonomic status
Conventionally, "white witch" refers to two very similar species of Thysania listed in the GBIF database: T. agrippina and T. pomponia. However, a 2016 publication establishes a new species among the subset of moths previously identified as T. agrippina. Thysania winbrechiini is differentiated from T. agrippina by morphological features and DNA evidence. T. winbrechiini is further categorized as containing two subspecies, and the authors also define a subspecies of T. agrippina, T. agrippina siriae. A note of caution: There is a concern among taxonomists about the pace at which limited data are being used to describe new species, by authors with a penchant to publish in obscure journals. That concern has been raised in the case of several hundred "Brechlin and Meister species", which are often nominated on the basis of DNA alone.
