Spongy Moth

The spongy moth is an invasive species that causes harm to the ecosystem of Colorado.

Spongy Moth Caterpillar. Dennis Wilkinson CC SA-BY-NC

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About This Species

The spongy moth is not native to Colorado or the United States. ​It was accidentally introduced to Massachusetts in 1869 from Europe. By 1902 it was widespread in the New England states, eastern New York, and regions of New Jersey.

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Physical Characteristics

The head of a mature caterpillar is yellow and black, with 5 pairs of blue spots (tubercles) on the abdomen and thorax. Behind the blue spots are 6 pairs of brick red spots. The pupa is dark reddish-brown and is held in place to an object by small strands of silk. The adult male spongy moth is a dark buff and flies readily during the day. Adult female spongy moths are white with black, wavy markings. They have robust abdomens and do not fly. The wingspan could reach 5 cm. ​​

Habitat

It is well established in oak hardwood forests of the eastern United States, but could survive in urban settings as well. 

Diet

​​Studies have shown that spongy moth larvae could feed on at least 500 species of plants that include trees, shrubs, and vines. In the eastern United States, the spongy moth prefers apple, speckled alder, basswood, gray and river birch, hawthorn, oak, poplar, and willow. They feed on foliage and remain on host plants.

Reproduction

The egg masses contain 400-600 eggs and are light tan, with black, pellet-like eggs inside. The larval stage, or caterpillar, is hairy, growing 50-65 mm long at maturity. The egg masses are deposited by females in July and overwinter on trees, stones, and other substrates. The eggs then hatch from late April through mid-May. The first instar larvae can be dispersed by wind.  The larvae reach maturity from mid-June to early July. The migrating caterpillars are often a nuisance toward the end of June. Pupation occurs on tree bark, stones, and buildings during late June and early July. Adults emerge starting in late June with peak emergence in mid-July.

Insect
Lymantria dispar