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Gypsy Moth (Lymantria dispar)

Detailing the identifying qualities of the Gypsy Moth, including physical features and territorial reach.

 Updated: 8/31/2017; Authored By Staff Writer; Content ¬©

  Gypsy Moth  
Picture of Gypsy-Moth

The unwelcome, exotic Gypsy Moth travels across a large range, and every few years, becomes a notorious pest in hardwood forests.

The unassuming brown Gypsy Moth came to North America from Europe through an amateur entomologist who moved here from France. A few of the adults he was studying escaped, and despite his pleas for help in containing them, little notice was given to the moths until they become a force to be reckoned with. The hungry caterpillars feed on a variety of hardwood tree leaves. Their appetite and mobility allow they to defoliate trees quickly. Older caterpillars feed day and night. Young caterpillars catch a breezy ride on a thread of their own silk to other trees if competition for leaves is too stiff. Still others are transported unwittingly by people who spend time in infested areas camping. Once trees lose too many leaves, they tap into their food reserves to grow a second batch in order to continue to make energy through the rest of the summer and fall. This weakens their reserves, and after years of such lost energy, they may die. Fortunately, a fungus that infects the moth helps to bring their numbers down to an insignificant level. It takes time for this fungus to make an impact though and years can pass before a real change can be seen in forests. Some areas see a return every few decades, especially in times of drought when fungi struggle to thrive. Beetles and birds are also natural predators for the Gypsy Moth and its larvae, so small populations are manageable. Removing caterpillars and banding tree trunks with sticky trap tape can help trees, too. In forests that have dense moth populations, professional arborists and forestry management have used aircraft to disperse insecticidal spray to curb deforestation.

Males and females are active in summer and die in winter. In autumn, females lay fertilized eggs in areas near their own upbringing. Eggs overwinter and larvae emerge in the spring. Caterpillars are hairy and brown with five blue dots and 6 red dots forming a line down its back (dorsal side). Look for them in hardwood forests with a mix of trees like pine, oak, maple and others. Check the tree canopy to see if leaves are skeletonized, missing or thinned for indications of caterpillar feeding.

Gypsy Moth Information

Category: Butterfly or Moth
Common Name: Gypsy Moth
Scientific Name: Lymantria dispar

Taxonomy Hierarchy

 Arrow graphic Kingdom: Animalia
  Arrow graphic Phylum: Arthropoda
   Arrow graphic Class: Insecta
    Arrow graphic Order: Lepidoptera
     Arrow graphic Family: Erebidae
      Arrow graphic Genus: Lymantria
       Arrow graphic Species: dispar

Size, Identifying Tags and Territorial Reach

Size (Adult, Length): Size (Adult, Length): 26 mm to 38 mm (1.014 inches to 1.482 inches)
Identifying Colors: brown, black
Additional Descriptors: harmful, flying, antennae, feathery, round

North American Territorial Reach (Though Not Limited To): Connecticut; Delaware; Illinois; Indiana; Iowa; Kansas; Kentucky; Louisiana; Maine; Maryland; Massachusetts; Michigan; Minnesota; New Hampshire; New Jersey; New York; North Carolina; North Dakota; Ohio; Pennsylvania; Rhode Island; South Dakota; Tennessee; Vermont; Virginia; West Virginia; Wisconsin; New Brunswick; Newfoundland and Labrador; Nova Scotia; Ontario; Prince Edward Island; Quebec

A Note About Territorial Reach: Keep in mind that an insect's reach is not limited by lines drawn on a map and therefore species may appear in areas, regions and/or states beyond those listed above. Insects are driven by environmental factors, food supplies and mating patterns and do not nescessarily work within hard-and-fast territorial lines like we humans do.

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