Content:
- Tent Caterpillar Facts
- Fact 1 – They Are Communal
- Fact 2 – Their Tents
- Fact 3 – Pheromone Trails
- Fact 4 – They Keep Each Other Warm
- Fact 5 – Dangerous to Pregnant Mares
- Fact 6 – Cyclical Outbreaks
- Fact 7 – Favorite Trees
- Fact 8 – Tent Caterpillar Predators
- Fact 9 – Harmless to Children
- Fact 10 – Species of Tent Caterpillars
- Fact 11 – Raining Pellets
- Fact 12 – Female Lifecycle
- Fact 13 – How to Get Rid of Tent Caterpillars
- In Conclusion
When talking about tent caterpillars, it is actually referring to the larvae stage of the tent caterpillar moth. When they mature and become moths, they are brown or tan in color and they have a 1 ½ inch wingspan. But the caterpillar is up to 2 ½ inches in length, black with rows of white stripes or dots, and short hairs all over the body.
The adult moth lays the eggs in a wrapping that looks like a tube that is usually attached to a twig or small tree branch. Each ‘tube’ can contain up to 350 eggs, and these hatch in the spring. These egg masses are often found in cherry trees, which is a favorite food of the caterpillar.
If you have a cherry tree you most likely despise the tent caterpillar, but what do you really know about these hairy wriggly creatures? Here are some facts you may find surprising.
Tent Caterpillar Facts
Fact 1 – They are Communal
Unlike many other caterpillars, the tent caterpillar likes to live with others inside one silk tent. They are very social caterpillars and are known to show a variety of social behaviors.
When the eggs hatch, these caterpillars will live together for up to 8 weeks until it is time for them to metamorphose into moths.
Fact 2 – Their Tents
Many species of tent caterpillar will build one large tent for the whole family to live in while they are in the caterpillar stage. This tent becomes a home base for the caterpillars, so while they traverse the branches of a tree for food, they will return to their tent. Each caterpillar spins silk to contribute to the construction of the tent.
Surprisingly, the caterpillars undertake any repairs or maintenance to the tent before they go out seeking food each day. In between meals, they rest in the tent where they are somewhat protected from any predators.
Fact 3 – Pheromone Trails
The Eastern tent caterpillar leaves a trail of pheromones to communicate with their sibling caterpillars. They have the ability to utilize different pheromones depending on whether they are marking recruitment or an exploratory trail. If a caterpillar comes across an exploratory trail, it instantly knows that another caterpillar is already searching that tree branch from food, and it will move off in another direction.
When a caterpillar finds a good source of leaves, it will use the recruitment trail to signal to the others to come and join in the feast.
Fact 4 – They Keep Each Other Warm
Because Eastern tent caterpillars are active in the cooler weather of spring, they rely on each other to stay warm. The nights can get very cold, so they huddle together to reduce the impact of any wind when they are outside the tent, and inside the tent to stay warm overnight.
During the day, they will soak up the sunshine to stay warm. The construction of the tent is so magnificent it has layers, so if it gets too hot inside, the caterpillars can move to the shady side and hang separately, or if it’s too cold, huddle together.
Fact 5 – Dangerous to Pregnant Mares
The Eastern tent caterpillar can have a catastrophic effect on pregnant horses which can lead to the horse aborting the foal late in the pregnancy term.
Although these caterpillars are normally harmless, if they are eaten by the horse the tiny hairs can penetrate through the intestinal wall. This allows bacteria into the organs including the amniotic sac surrounding the foal.
Fact 6 – Cyclical Outbreaks
Like many other insects, outbreaks of tent caterpillars can be cyclical. Usually, somewhere between every 9 and 16 years, the number of tent caterpillars can reach such a peak that the trees can suffer significant damage.
When there has been a particularly heavy infestation, the number of caterpillars will normally decline the following year.
Fact 7 – Favorite Trees
The tent caterpillar prefers hardwood trees that are deciduous, with the cherry tree being their absolute favorite. Other trees and bushes that are popular with these caterpillars include:
- Apple
- Elm
- Cottonwood
- Oak ash
- Oak
- Plum
- Peach
- Sweetgum
- Sugar maple
- Willow
- Wild cherry
Fact 8 – Tent Caterpillar Predators
The common predators of tent caterpillars are parasitic wasps and birds.
The birds like to dine on the caterpillars, but the wasps bore into the caterpillar and eat them while they are still alive from the inside out.
Fact 9 – Harmless to Children
Children are particularly fond of caterpillars and will often play with them if they get the chance. The good news is that the tent caterpillar is not dangerous, as they are not poisonous.
This doesn’t mean they should eat them of course! But, the small hairs on the caterpillar’s body can be irritating to the skin of both children and animals.
Fact 10 – Species of Tent Caterpillars
There are at least twenty-six species of tent caterpillars, and it’s believed there may be some subspecies as well. They are below to the moth genus Malacosoma and the family is Lasiocampidae. Six species have been identified in North America and the others in Eurasia.
Eastern Tent Caterpillar – this species is normally found east of the Rockies and into Southern Canada. The caterpillars are black and lightly hairy and have two rows of pale blue spots, one on each side. Down the center of their backs is a white stripe. They are fond of cherry, crabapple, and apple trees.
Western Tent Caterpillar – more commonly found in the northern and western areas of the United States and Canada, these caterpillars are very hairy. They are a yellow-brown color and have a row of blue spots along their backs. In between the spots are orange spots. They favor trees such as poplar, apple, cottonwood, plum, willow, oak, and roses.
Forest Tent Caterpillar – this species favors hardwood trees and is found throughout the United States and Canada. This caterpillar doesn’t make a tent like the others; instead, it makes a silk mat. They have white spots running down their backs. They favor cherry, maple, aspen, hawthorn, and oak trees.
Fact 11 – Raining Pellets
The tent caterpillar is known to void half of its ingested energy as fecal pellets. Therefore if there is a large colony of caterpillars, a huge volume of pellets can be produced.
During outbreaks of forest tent caterpillars, the number of pellets dropping from the treetops can sound like rain falling.
Fact 12 – Female Lifecycle
The lifecycle of the female moth is incredibly short. As soon as she emerges from the cocoon, she secretes a pheromone that attracts the male moth to her. In the early evening, mating normally takes place, although the female is already full of eggs.
The eggs are laid the same evening. Soon after depositing the eggs, the female moth dies, so the entire lifecycle of the female moth can be less than 24 hours in duration.
Fact 13 – How to Get Rid of Tent Caterpillars
Although they are not dangerous to humans, the damage they can cause to trees is astonishing, so many people look for ways to get rid of the caterpillars. There are a number of ways to get rid of them, which all result in the death of the caterpillar. The simplest method is to destroy them with a sharp stick, but some may find this a little brutal.
One of the best methods is to destroy the tent of the caterpillar. Once you remove their home, they become prey to other animals and birds, which will happily pick them off one by one and eat them.
The best time for getting rid of tent caterpillars is either early in the morning or in the evening while they are still in the tent. Once the sun is out and they have gone out foraging for food, it is much harder to kill them. If you can see the eggs or tents, you can either pick them off with your hands or prune that part of the branch of the tree and destroy it.
Planting attractants for parasitic wasps can help gain control over the tent caterpillar population. These natural predators can do a good job of eliminating a smaller colony, but if there is a large outbreak it may not be as successful. Likewise, by creating a garden environment that is attractive to birds you can also manage the population of tent caterpillars.
Small infestations of tent caterpillars can be destroyed by dropping the tent into soapy water. However, if you have a large infestation, you are better use a contact insecticide. The most effective of these is bacillus thuringiensis which will only kill the tent caterpillar and nothing else in the environment. You simply spray it directly onto the tents and onto the foliage of the trees.
There is one item found in every kitchen that can successfully eliminate a whole colony of tent caterpillars, and that is vegetable oil. Once the caterpillars are snugly tucked up in their tent, spray the whole tent with vegetable oil. Because caterpillars breathe through their skin, the oil will cause them to suffocate and die.
In Conclusion
Although these caterpillars can be disastrous for trees, they really are incredible construction experts.
The way they interact with each other, live together, and socialize is quite remarkable, and if you get the chance to watch them in action, you will find it quite intriguing.