|
May 2008
An "in-tents" encounter with nature
I was in the grocery store looking for cereal when a little boy in a neighboring shopping cart waved to me. “See my bug?” he said, beaming. Inside his glass jar was one tiny occupant: a black caterpillar with blondish hairs along its sides and a long, blue stripe down its back. I admired his new little pet, then exchanged smiles with his mom before moving on to find my groceries.
It is that time of year: the Eastern Tent caterpillars are out and they seem to be everywhere. Every kid seems to find one on the playground, and every bug-hating adult seems to be in permanent cringe.
As a bug-loving adult, I am in hog heaven. Much like that kid in the grocery cart, I find these bugs really fun to watch.
I know I am not supposed to like the tent caterpillars so much. I know people think of them as destructive, annoying and sometimes gross in their abundance. But to me and my kids, those tent caterpillars are almost like live teddy bears. You can pick them up, you can stroke their backs, you can laze around on your belly watching them crawl through the grass. They are ambassadors from the friendly side of nature. Nobody gets stung, bitten or surprised, except perhaps the bugs themselves. Everyone can take a turn letting one walk on their fingers. They are a sign that school is almost over and sunny days of vacation are close on the horizon.
A lot of the cherry trees along the edges of parks are home to these caterpillars. In early March when their eggs hatch, these bugs will emerge and begin to build their gossamer tents in the v-shaped spaces of tree branches. They leave their tents to feed on leaves when it is cool in the morning or around dusk. On rainy days and during the heat of the day, they mostly stay inside their tents.
People often panic when they see tent caterpillars in their yards because they mistakenly assume that tent caterpillars are the same as gypsy moths. The two creatures do vaguely resemble each other in the caterpillar stage. But the blue stripe down their sides lets you know you are looking at the tent caterpillars. Also, I personally think the gypsy moth has a much less appealing appearance; it seems more prickly, and less roly-poly looking. There seems to be something much more menacing in the gypsy moth’s demeanor.
This could just be my bias, however, since I know how destructive the gypsy moth can be in comparison to the eastern tent caterpillar. There are big differences between the eating habits of the two creatures. Gypsy moths need to eliminated whenever they are found, because their munching is voracious and can quickly destroy trees. These caterpillars where imported in the mid 1800s in what seems to have been a failed attempt to establish a cheap alternative to silk production in the U.S.
In contrast, eastern tent caterpillars are native and are readily eaten by several species of our native birds, including Baltimore orioles. In more wild areas, toads are also known to eat them.
The tents the caterpillars form are their protection from such predators, but they are not cocoons. Once they’ve hatched from their shiny, black egg mass in early spring, the caterpillars build the tent and live there as a group. All of the caterpillars from one egg mass usually stay together in the same silken structure. They leave to feed at different times throughout the day. Once they’ve reached full mature caterpillar size in late spring, they move away from their host tree to find a place to spin their own individual cocoon.
This is when most people begin to find them on sidewalks and along playgrounds. Because we see so many of them during this time, people sometimes panic about the caterpillars’ potentially destructive behavior. But. by this point. they have eaten their fill of leaves and are now more interested in finding a spot where they can begin metamorphosis.
Most insect experts seem to agree that tent caterpillars will not cause large scale harm to trees. A fact sheet published by the University of Kentucky, for example, points out that although “tent caterpillars can nearly defoliate a tree when numerous, the tree will usually recover and put out a new crop of leaves.”
But in places like Silver Spring, Wheaton and Takoma, these caterpillars can still be annoying to homeowners. A tree without leaves in summer is not really nice to look at, even if you know it will eventually recover. This is partly because many of us have only one or two trees to enjoy in our yards and we sometimes get rather protective about their health. Also, a tree which is already weak can sometimes be further weakened by these insects.
Luckily, controlling them is usually pretty easy. The best, most effective method of control must be undertaken in the early spring or winter, when the shiny black egg masses can easily be removed from cherry tree branches. (For a picture of what these look like, you can go to www.ca.uky.edu/entomology/entfacts/ef423.asp.)
If you find that the caterpillars have built a tent in your trees, you can also remove the branch holding the tent. This is not a task for those who are squeamish around insects. But it is pretty easy to do, and if you take on the removal and disposal when the tent is full, you can be assured most of the caterpillars will be inside.
And if you decide not to remove the tent caterpillars, that should be okay, because most of the time these caterpillars feed on wild black cherry trees, sprout up everywhere and are able to grow quite happily in the oddest locations when given complete neglect. The edges of parks and urban ball fields are often dotted with them. This is one reason why you can sometimes see bored little leaguer players sitting down in the outfield to watch the caterpillars go crawling by.
As the next few weeks unfold, my kids and I will be watching the trees and waiting with our bug jars open, faces pointed up toward the warm sunshine. Let others cringe. For me, this is the epitome of early summer.
Read more Sligo Naturalist
Comments:
|
