Lymantria dispar dispar

Carl Linnaeus first described the species as Phalaena [Bombyx] dispar in 1758. The word dispar is derived from the Latin for "unequal" and it depicts the differing characteristics between the sexes. L. d. dispar versus L. dispar usage For the purposes of taxonomy, the common names European gypsy moth and North American gypsy moth represent the same subspecies, L. d. dispar, as opposed to subspecies of L. dispar from Asia. Confusion over the species and subspecies is widespread. For regulatory purposes, the U. S. Department of Agriculture has defined Asian Gypsy Moth as "any biotype of Lymantria dispar (sensu lato) possessing female flight capability". despite Lymantria dispar asiatica not being the only classified subspecies that is capable of flight; even females of L. d. dispar can fly, if only very weakly. Traditionally, all L. dispar have been referred to as gypsy moth, including when referring to Japanese, Indian, and Asiatic subspecies. == Common name ==

In the species' native area, the English common name is "gypsy moth". This led the Society to select a replacement name through a consultative process. In January 2022, they proposed the name spongy moth, in reference to the spongy mass of the egg casing. This new common name was formally adopted in North America in March 2022. == Range ==

L. d. dispar is indigenous to Europe. In southeastern England, it was widespread in the 19th century, but became extinct except for occasional migrants soon after 1900. It then recolonised naturally from the 1990s; colonies were found in London from 1995 and Buckinghamshire from 2005, and more widely since. Introduction to North America Lymantria dispar dispar was first brought to North America in 1869 As noted in The Gypsy Moth (1896) by Forbush and Fernald, the moth was considered a nuisance just ten years after their release. Eventually they would reach the Pacific Northwest, sporadically invading but so far not becoming established there, due to successful eradication campaigns. A study published in 2012 suggests that storms can accelerate the spread, hypothesizing that strong easterly winds carried larvae across Lake Michigan to Wisconsin, a distance of at least . Firewood transport is a common way for the eggs to spread, since the moths will lay their eggs on dead wood. Attempts have been made to limit the movement of firewood to reduce the moth's spread. == Life cycle ==

Eggs Egg masses are typically laid on branches and trunks of trees, but may be found in any sheltered location, including rocks, foliage and vehicles. Females are flightless, so they lay eggs on a surface near where they emerged from their pupa. The eggs are covered in a coating of hairs. The covering provides protection from predators and parasites, and may be important for insulating the eggs from cold and for sealing in moisture. The egg masses are buff yellow-brown, likened to a manila folder, but may bleach out over the winter months. As the female lays them, she covers them with hair-like setae from her abdomen. Egg clusters contain from 100 to 1000 eggs. Due to the appearance of the eggs, several common names have emerged; the German Schwammspinner (literally "sponge spinner") and French la spongieuse refer to the spongy texture of the egg cluster. Pupae The larvae reach maturity between mid-June and early July, then enter the pupal stage, during which larvae change into adult moths. Pupation lasts from 14–17 days. The adult moth will emerge, fully developed, by splitting the pupal skin. The females are bigger than the males. Another important difference between the sexes is that females possess fully formed wings but do not fly. Female flight is common in Eurasia, but these moths may be of a different species. Courtship is not elaborate: the female must raise her wing to allow the male to couple with her. The moths remain in copula for up to an hour, but the transfer of the spermatophore is usually accomplished within 10 minutes. A male moth can inseminate more than one female. Multiple mating in females is possible but uncommon, as the female stops releasing the attracting pheromone after mating. After mating, the females begin depositing the eggs. Adult moths live about one week. They do not possess an active digestive system and cannot feed, but they can drink in moisture. The reproductive chance for females lasts about two days, with the pheromone for attracting males being diminished by the third day. Due to the pheromone's potency, most females will mate. Females lay their eggs on trees, shrubs, rocks, vehicles, and plants of many types. Each of them typically lays about 500 eggs. The eggs are covered with a peachy fuzz that can cause serious rashes if touched by bare skin or fur. == Behavior ==

Many environmental factors such as resource availability, predator density and sexual competition are known to affect behavior from its larval stage to adult stage. A population will exist for many years in low densities. When the population enters the release phase, it rapidly expands to the outbreak phase where the population size will rise several orders of magnitude and fall back within only a few generations. Feeding The gypsy moth brings one of the largest impacts in defoliation of deciduous trees in the Northern Hemisphere. Since its introduction into the United States in 1868 or 1869, it has spread both west and south, now taking over most of the hardwood forests in the eastern United States and Canada. Predation Many species have been identified as preying on L. dispar. Some species, such as the white-footed mouse or Anastatus disparis, have a significant impact on the population dynamics of the moth. On the other hand, avian predation and invertebrate predation show only small effects on population dynamics. Small mammals The white-footed mouse (Peromyscus leucopus), is considered important for regulating sparse moth populations. Rodents consume larvae and pupae that seek resting sites near or on the ground. The population in Austria suffered high parasitism by the tachinids Parasetigena silvestris, which may have contributed in prevention of further increase in L. dispar in this locality. Pathogens Gypsy moth populations in different locations show vulnerability to different viral species. Nuclear polyhedrosis virus caused significant mortality in some cases. The most important pathogen is the Lymantria dispar multicapsid nuclear polyhedrosis virus (LdMNPV), sometimes referred to as NPV or Borralinivirus reprimens. Viral particles consumed by the larva when eating through the egg chorion will kill them during the first instar. The bodies disintegrate, spreading the virus on the foliage, which will then be consumed by other larvae. Outbreaks of the virus result in high larva mortality, It was first introduced to North America around 1910, though was not an effective control until the 1980s. Other adaptations Population density of larvae plays a major role in their behavior. At low density, larvae remain inactive during the day, but in high populations become hyperactive. == Impact ==

near Snow Shoe, Pennsylvania, in July 2007. The light green patches on hilltops are trees that had begun refoliating by the time this picture was taken.|alt=Aerial photo showing gypsy moth defoliation of hardwood trees along the Allegheny Front near Snow Shoe, Pennsylvania, in July 2007. Some of the trees had begun refoliating by the time this picture was taken. The gypsy moth habitat overlaps with the northern tiger swallowtail (Papilio canadensis). Experiments indicate that known gypsy moth pathogens and gypsy moth bodily fluid negatively affect the survival of swallowtail larvae. Gypsy moth bodily fluid is lethal, and swallowtail caterpillars were prone to higher rates of parasitism when placed in the field near gypsy moth infestations. L. d. dispar causes widespread defoliation and costs the economy millions of dollars in damages. Total defoliation in America, from 1970 to 2010, was . The worst year was 1981 with defoliated. In 2010, were defoliated. Forest defoliation by the gypsy moths each year affects the populations and reproductive success of forest-dwelling birds. Nests placed in defoliated sites suffered a higher predation rate than those in non-defoliated sites. gypsy moths have a direct impact on avian behavior in the American forests. Rash The caterpillar has been reported to produce a poison ivy–like rash when some people come into contact with the hairs of the larvae (caterpillar) stage. The contact can be direct or even if the small hairs are carried by the wind and onto the skin or clothing of a person. Such rashes were documented in the early 1980s, during a major infestation in the Northeastern United States. In coastal Maine and Cape Cod, Massachusetts, caterpillar-triggered rash is much more likely due to exposure to brown-tail moth (Euproctis chrysorrhoea). == References ==