forest tent caterpillar

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Uploaded on May 10, 2010

A spring trip to Addington Highlands, Ontario. May 8, 2010.

The Forest Tent Caterpillar Moth (Malacosoma disstria) is the larva of a North American moth, found throughout the United States and Canada, and most common in the eastern regions.

These tent caterpillars do not make tents, rather they weave a silky sheet where they lie together during molting. They lay down strands of silk as they move over branches and travel along them like tightrope walkers. However, it has been shown that a trail pheromone secreted from the ventral surface of the posterior tip of the abdomen rather than the silk guides and stimulates trail following. The caterpillar are social and travel and feed en masse. The caterpillars live in deciduous trees, which they strip of leaves after emerging from their eggs. The moths favor oak, sweetgum and tupelo, aspen trees, and sugar maple for oviposition but the larvae can be found feeding on many other species of woody trees or shrubs when they disperse from ovipositional trees during outbreaks. The females lay eggs in masses of up to 300, which are stuck to twigs and covered with a gluey cement called spumaline which prevents them from desiccating or freezing over the winter. The eggs hatch the following winter.

Malacosoma disstria
The caterpillars are considered problem is when their populations explode in the fall. They can completely consume a tree. The trees re-foliate quite quickly (within two weeks to a month) and produce enough new leaves to carry on photosynthesis. Under most circumstances, little lasting damage is caused to the trees; however the disappearance of foliage is an eyesore and can be an agricultural nuisance. On those rare occasions when infestations last for three years or more, significant levels of tree mortality will begin to emerge during the years following outbreak collapse. Large-scale tree mortality has been reported in only one instance, in northern Ontario, Canada, after two outbreak cycles in the early and late 1990s occurred back-to-back, resulting in more than six consecutive years of aspen defoliation in some areas.

One outbreak in upstate New York and Vermont began in 2002, with 650,000 acres (2600 km²) defoliated in New York and 230,000 acres (930 km²) in Vermont in 2005.

Forest tent caterpillars are just over 2 inches (5 cm) in length, black or dark brown or gray with blue and faint yellow longitudinal stripes. Each abdominal segment bears a white spot. The caterpillars have long setae, giving them a furry look. The adult moth that emerges after pupation is yellow or tan with a thick, short, furry body. The wingspan is about 1.5 inches (3 cm). It is rather strictly nocturnal, starting to fly soon after nightfall and by and by returning to rest in the latter half of the night (Fullard & Napoleone 2001).

It is not known with certainty how far egg-laden female moths tend to fly. There is one credible report of moths flying hundreds of kilometres with the assistance of an unusually strong wind. (wikipedia)

Uploaded on Jun 14, 2010

"If you're not a Buddhist you think there are Buddhists and nonBuddhists, but if you're a Buddhist you realize everybody's a Buddhist--even the bugs." --Shunryu Suzuki Photographed at Turtle River State Park, North Dakota (14 June 2010).

Uploaded on Jul 6, 2010

Photographed at the Turtle River State Park, North Dakota (06 July 2010).

Uploaded on Jun 12, 2010

An unusually blue specimen. Photographed at Turtle River State Park, North Dakota (11 June 2010).

Uploaded on Jun 24, 2010

Photographed at Turtle River State Park, North Dakota (24 June 2010).