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Lymantria dispar

What do they look like?

Male and female gypsy moths are different colors from each other. Males are light brown with dark brown wings that have black bands on them. Females are mostly white, and also have dark bands on their wings. Males have feathery antennae, and females have antennae that look and feel like threads. Females are are a little bit bigger than males, and their bodies are covered with tiny hairs. Adult gypsy moths are normally 15 to 35 mm long, and their wingspan is 37 to 62 mm. There are three subspecies, which are European, Asian, and Japanese gypsy moths. They all look similar, but Asian gypsy moths usually have the biggest largest larvae. ("Gypsy Moth", 2009; "Lymantria dispar (insect)", 2011)

Gypsy moth larvae are black, hairy caterpillars. As they get older, they grow two rows of blue spots on their backs that then turn red. Each spot has a patch of yellow or brown hair growing out of it. Their legs are dark red. ("Gypsy Moth", 2009; "Lymantria dispar (insect)", 2011)

  • Sexual Dimorphism
  • female larger
  • sexes colored or patterned differently
  • Range length
    15 to 35 mm
    0.59 to 1.38 in
  • Range wingspan
    37 to 62 mm
    1.46 to 2.44 in

Where do they live?

Gypsy moths originally lived in southern Europe, northern Africa, central and southern Asia, and Japan. They were introduced into the United States and Canada in 1869, and have spread quickly across North America. There are a lot of them in the northeastern United States. ("Lymantria dispar (insect)", 2011; Munson and Hanson, 1981)

What kind of habitat do they need?

Gypsy moths live in forests or open forests, where the trees and shrubs they live on take up at least 20% of the space. They live in temperate climates, meaning places that have seasons. They are found near humans in urban and suburban areas. ("Lymantria dispar (insect)", 2011; McManus, et al., 1989)

How do they grow?

Gypsy moths go through 4 stages of development, which are called: egg, larva, pupa, and adult. Females lay eggs in July or August on the trunks or branches of trees. After 4 to 6 weeks, the embryos develop into larvae. The larvae stay dormant in their eggs throughout the winter. They hatch in the next spring, together when the trees they live on get buds on them. As gypsy moths get older, larvae shed their skin and grow a new, larger one. This usually happens 5 or 6 times, and then they become pupae in June or July. They stay as pupae for 7 to 14 days. Males come out first, usually 1 to 2 days before females. Then, females come out and gypsy moths breed. Both parents die after the eggs are laid, and the cycle repeats. ("Gypsy Moth", 2009; McManus, et al., 1989)

How do they reproduce?

Female gypsy moths release chemicals called pheromones to attract males. Females lay eggs 24 hours after mating. Males mate with more than one female. ("Gypsy Moth", 2009)

Adult gypsy moths breed one time per year, usually in July or August. Females usually lay about 1,000 eggs per breeding season on tree trunks and branches. It only takes about 1 month for larvae to develop inside the eggs, but they usually take 8 to 9 months to hatch. Larvae are attracted to light after they hatch. They move up their host trees by spinning silk threads. They live in the tops of the trees until they become pupae, and develop in a silk net on or near their host tree. After they become pupae, it takes about 2 weeks for them to become adults. Gypsy moths live for about 11 months before they can reproduce. ("Gypsy Moth", 2009; "Lymantria dispar (insect)", 2011)

  • How often does reproduction occur?
    Gypsy moths breed once yearly.
  • Breeding season
    Females lay their eggs in July or August.
  • Average eggs per season
    1,000
  • Average gestation period
    8 months
  • Range time to independence
    8 to 8 weeks
  • Average age at sexual or reproductive maturity (female)
    11 months
  • Average age at sexual or reproductive maturity (male)
    11 months

Adult gypsy moths live until the females lay their eggs on the trunks and branches of the trees where they live. Females lay their eggs nearby the place where they developed as pupae. The parents die right after the females lay their eggs. (McManus, et al., 1989)

  • Parental Investment
  • female parental care
  • pre-fertilization
    • provisioning
    • protecting
      • female
  • pre-hatching/birth
    • provisioning
      • female
    • protecting
      • female

How long do they live?

Gypsy moths breed once a year, and live for about 12 months. They are eggs for 8 to 9 months, larvae for 2 to 3 motnhs, and pupae for about 2 weeks. They live about 1 week as adults and then lay eggs. ("Gypsy Moth", 2009)

  • Average lifespan
    Status: wild
    12 months

How do they behave?

Gypsy moths larvae stay on the same host tree as they develop. In the first three stages of development, they stay in the tops of the trees. In the last 2 or 3 stages of development, they crawl down the tree during the day and rest under bark or branches. Since they are more vulnerable to predators, they go back up into the treetops at night. Gypsy moth larvae only leave their trees if they blown away or moved by something else. Pupae also stay on the same tree. Once the males come out as adults, they fly through the forest in zigzags looking for females. Then, females attract males with chemicals called pheromones. ("Lymantria dispar (insect)", 2011; McManus, et al., 1989; Munson and Hanson, 1981)

Gypsy moths can fly, even though they spend most of their lives in the same tree. They are also moved around by humans. Big groups of them move from place to place looking for new trees where they can get leaves to eat. Asian gypsy moths can fly a long ways, so they spread quickly. European gypsy moths can't fly, so they take a long time to spread. However, their eggs get moved around on vehicles, equipment, shipping containers, and law furniture. They can also move short distances attached to travelers. Finally, they can crawl to the tops of trees and let the wind carry them a long ways. ("Lymantria dispar (insect)", 2011; McManus, et al., 1989; Munson and Hanson, 1981)

Home Range

Gypsy moth larvae and pupae stay on the host tree where they hatched. Adults fly to different trees in order to mate. Scientists don't know exactly how big their territories are. (McManus, et al., 1989)

How do they communicate with each other?

Like most other insects, gypsy moths get information about their environment from sight and touch organs like legs and wings. They can also see ultraviolet light from the sun. After the larvae hatch from eggs, they are drawn to the light and move up the trees where they live. They end up in the tops of the trees and can be moved around by the wind. They communicate using pheromones, which females give off to attract males. Scientists understand this chemical very well and have actually recreated it in laboratories. ("Gypsy Moth", 2009)

What do they eat?

Gypsy moths eat the leaves of more than 500 kinds of trees and shrubs. They prefer to eat oak trees, alber broadleaf trees, Douglas firs, and western hemlock needle trees. The mouths of adults aren't completely developed, so only the larvae eat from the trees. ("Gypsy Moth", 2009; "Lymantria dispar (insect)", 2011)

  • Plant Foods
  • leaves

What eats them and how do they avoid being eaten?

Gypsy moths are eaten by wasps, flies, ground beetles, ants, and spiders. Birds like chickadees, bluejays, nuthatches, towhees, and robins also eat them and compete with them for resouces. In addition, mammals such as white-footed mice, shrews, chipmunks, squirrels, and raccoons are also predators. When there are a lot of gypsy moths, they are also eaten by Calosoma beetles, cuckoos, starling grackles, and red-winged blackbirds. (McManus, et al., 1989)

  • These animal colors help protect them
  • cryptic

What roles do they have in the ecosystem?

Gypsy moths eat leaves from trees. They depend on the trees where they live. The more they depend on the tree, the more they eat all of its leaves. They like oak trees best, but can live on and eat most kinds of trees and shrubs. They don't live on ash trees, tulip poplars, or sycamores, and only rarely live on black walnut trees. Gypsy moth populations can also get diseases like wilt diseases, which kills larvae and pupae. ("Gypsy Moth", 2009; "Lymantria dispar (insect)", 2011; McManus, et al., 1989; Munson and Hanson, 1981)

Gypsy moths have go through large, fast increases in their populations, called outbreaks. At first, the number of gypsy moths is low. This can last for several years. In the release phase, the number of gypsy moths increases quickly over 1 to 2 years. Next, there are a lot of gypsy moths, and many of the leaves of the trees are eaten for 1 to 2 years. Then, there are too many gypsy moths, so they end up getting diseases or starve to death. Afterwards, there are very few gypsy moths, and the population returns back to low levels in the first phase. ("Gypsy Moth", 2009; "Lymantria dispar (insect)", 2011; McManus, et al., 1989; Munson and Hanson, 1981)

Species (or larger taxonomic groups) used as hosts by this species
  • Several hundred species of trees and shrubs are used as hosts by gypsy moths.

Do they cause problems?

Gypsy moths are well-known because they are able to eat all of the leaves on almost any kind of tree. If they eat more than half of the leaves on the top of the tree, they usually die. Some trees can survive having all of their trees eaten once or twice, but more than that usually kills the tree. Growing all of the leaves all over again takes a lot of energy for the tree, and trees that have been eaten by gypsy moths are more likely to get attacked by viruses or insect parasites. This costs money for the timber business, removing dead trees, and reducing property values. It can also lead to loss of part of the forest, which causes flooding and loss of species diversity. Since 1970, gypsy moths have destroyed about 30 million hectares of forests in the United States. They are found in most of the eastern United States, and spread 3 to 10 miles per year. This means they will probably be in half of the United States by 2015. In addition, some people are allergic to the hairs on gypsy moth larvae. ("Gypsy Moth", 2009; "Lymantria dispar (insect)", 2011; McManus, et al., 1989)

  • Ways that these animals might be a problem for humans
  • crop pest

How do they interact with us?

When gypsy moths defoliate trees, they open up the tops of the trees and reduce overcrowding of trees. ("Lymantria dispar (insect)", 2011)

Are they endangered?

Gypsy moths are not endangered, vulnerable, or threatened. They are really bad pests and scientists try to figure out how to get rid of them. ("Gypsy Moth", 2009)

Contributors

Aaron Wasserman (author), University of Michigan-Ann Arbor, Catherine Kent (editor), Special Projects.

References

United States Department of Agriculture. Diseases of the gypsy moth: How they help to regulate populations. 539. Washington, D.C.: Agriculture Handbook. 1979.

United States Department of the Interior National Park Service. Gypsy Moth. 2. Washington, D.C.: Integrated Pest Management Manual. 2009.

National Biological Information Infrastructure (NBII) and IUCN/SSC Invasive Species Specialist Group (ISSG). Lymantria dispar (insect). 49. Baltimore: Global Invasive Species Database. 2011.

United States Department of Agriculture. The homeowner and the gypsy moth: Guidelines for control. 227. Washington, D.C.: Home and Garden Bulletin. 1979.

Barbosa, P., J. Greenblatt. 1979. Suitability, digestibility and assimilation of various host plants of the gypsy moth Lymantria dispar L.. Oecologia, 43/1: 111-119.

Elkinton, J., W. Healy, J. Buonaccorsi, G. Boettner, A. Hazzard, H. Smith, A. Liebhold. 1996. Interactions among gypsy moths, white-footed mice, and acorns. Ecology, 77/8: 2332-2342.

Gould, J., J. Elkinton, W. Wallner. 1990. Density-dependent suppression of experimentally created gypsy moth, Lymantria dispar (Lepidoptera, Lymantriidae), populations by natural enemies. Journal of Animal Ecology, 59/1: 213-233.

Hajek, A., P. Tobin. 2009. North American Eradications of Asian and European Gypsy Moth. Dordrecht, Netherlands: Springer.

Jones, C., R. Ostfeld, M. Richard, E. Schauber, J. Wolff. 1998. Chain reactions linking acorns to gypsy moth outbreaks and Lyme disease risk. Science, 279/5353: 1023-1026.

Liebhold, A., J. Halverson, G. Elmes. 1992. Gypsy moth invasion in North America — a quantitative analysis. Journal of Biogeography, 19/5: 513-520.

McManus, M., N. Schneeberger, R. Reardon, G. Mason. 1989. Forest Insect and Disease: Gypsy Moth. Washington, D.C.: United States Department of Agriculture Forest Service.

Munson, A., J. Hanson. 1981. Pest Alert: Gypsy Moth. St. Paul, MN: United States Department of Agriculture Forest Service.

Redman, A., J. Scriber. 2000. Competition between the gypsy moth, Lymantria dispar, and the northern tiger swallowtail, Papilio canadensis: interactions mediated by host plant chemistry, pathogens, and parasitoids. Oecologia, 125/2: 218-228.

Reineke, A., C. Zebitz. 1998. Flight ability of gypsy moth females (Lymantria dispar L.) (Lep., Lymantriidae): A behavioural feature characterizing moths from Asia?. Journal of Applied Entomology, 122/6: 307-310.

Roden, D., W. Mattson. 2008. Rapid induced resistance and host species effects on gypsy moth, Lymantria dispar (L.): Implications for outbreaks on three tree species in the boreal forest. Forest Ecology and Management, 255/5-6: 1868-1873.

Rossiter, M. 1991. Maternal effects generate variation in life-history - consequences of egg weight plasticity in the gypsy moth. Functional Ecology, 5/3: 386-393.

Timms, L., S. Smith. 2011. Effects of gypsy moth establishment and dominance in native caterpillar communities of northern oak forests. Canadian Entomologist, 143/5: 479-503.

Work, T., D. McCullough. 2000. Lepidopteran communities in two forest ecosystems during the first gypsy moth outbreaks in northern Michigan. Environmental Entomology, 29/5: 884-900.

 
University of Michigan Museum of ZoologyNational Science Foundation

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Wasserman, A. 2013. "Lymantria dispar" (On-line), Animal Diversity Web. Accessed October 20, 2014 at http://www.biokids.umich.edu/accounts/Lymantria_dispar/

BioKIDS is sponsored in part by the Interagency Education Research Initiative. It is a partnership of the University of Michigan School of Education, University of Michigan Museum of Zoology, and the Detroit Public Schools. This material is based upon work supported by the National Science Foundation under Grant DRL-0628151.
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