Depending on how you look at it, tent caterpillars begin as eggs,which are quite small and attached to the branch of one of the caterpillars' favorite (or tolerated) food sources. Here, that means red alder, black cottonwood, Nootka rose, willows, apples, cherries, laurel... any vaguely palatable species of deciduous tree or shrub. The eggs are laid in the mid-late summer, and overwinter until the spring-time signal that they should hatch.
In the spring they hatch by the millions, and begin to create this 'tent' that they can hide in. They also begin to voraciously eat the foliage of their host plants. As they get older they will stray more from the tent where their brethren still take refuge, and forage in small groups or by themselves.Eventually they wander off to pupate in a silky cocoon in the grass.
In the 'boom' years of the caterpillar's population, there is an unsurprising increase in organisms that parasitize them, a tachinid fly, parasitic wasps, viruses and bacteria. Thus, at some point the overwhelming parasitism and predation cause a 'bust' in the population, resulting in lower populations for a few years. Temperature and weather are also regulators of the caterpillars' populations. I'm thinking this is a 'boom' year.
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| Localized defoliation of an apple tree due to caterpillar foraging. |
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| Tent caterpillars on cherry laurel, a plant used heavily in landscaping despite its invasiveness. |
The caterpillars are actually rather pretty, as far as that kind of insect/life stage goes. The minutiae of tiny detail in blue spots and tufts of hair used in environmental sensing are incredible. They are just fun to look at.
The moth resulting of the cocooning stage is quite fuzzy and a caramelly brown color. Their antennae are large and plumed in a feathery fashion that many moths use; they sense one another's pheromones with these proportionally large antennae. And the cycle begins all over again. And now you know!
