Gypsy Moth

• GeneralA defoliating pest that can strip whole forests bare; the European females can barely fly.
• It reached North America by accident: in 1869 Étienne Léopold Trouvelot imported eggs to Medford, Massachusetts, to try crossing it with the silkworm and obtain a disease-resistant caterpillar. They escaped from his garden.
• He warned the local entomologists and nothing was done; twelve years later the population exploded and the first government insect eradication campaign in history was launched, and failed.
• Since 1980 it has defoliated more than 4,000 km² of US forest a year; in 1981 the figure was 52,200 km².
• Newly hatched caterpillars disperse through the air hanging from a silk thread, a process known as ballooning.
• The females cannot fly: they lay their eggs on the same trunk where they emerge, and dispersal depends on the caterpillars and on human transport.

Skeleton type

Invertebrate - chitin exoskeleton (insect)

Habitat and environment

Deciduous woodland of oak, holm oak and chestnut

Size at birth

First-instar larva of about 3 mm

Gestation / incubation

The eggs spend the winter in diapause and hatch in April-May, several months after the August laying

Litter / clutch size

A single clutch of 100 to 1,000 eggs in an egg mass covered with abdominal hairs; some sources cite up to 1,500

Sources consulted: https://en.wikipedia.org/wiki/Lymantria_dispar; Bugwoodwiki, Lymantria dispar; Columbia CERC, ficha de especie introducida; Univ. of Wisconsin Extension, ciclo biologico de Lymantria dispar; Bugwoodwiki; Animal Diversity Web / BioKIDS, Lymantria dispar; Monaco Nature Encyclopedia; Monaco Nature Encyclopedia, Lymantria dispar; Canadian Food Inspection Agency, ficha tecnica de Lymantria dispar

Best time: Adults between late June and September, peaking in July; caterpillars from April to early July