Not Just Another Tube Left In The Woods

Perhaps it’s a case of being in the right place at the right time. Or, taking the time to look. Really look.

You might stay there’s nothing extraordinary about pine needles, right? As you probably know, the needles (aka leaves) of Eastern White Pine, Pinus strobus grow in packets or bundles of five. W-H-I-T-E or M-A-I-N-E is a mnemonic we use to remember how many needles on the White Pine since they spell “white” for its name or “Maine” because it is the State tree.

A word of caution, however, in that department. If a White Pine has five needles, then a Red Pine, Pinus resinosa, must have three needles in a bundle, correct? False. They actually have two much longer and stiffer needles that break cleanly when bent in half.

Back to the White Pine of my attention. What I’ve been noticing is that suddenly there are clusters of needles bound together. This is the work of the larval form of a Pine Tube Moth, Argyrotaenia pinatubana. What typically happens is that the caterpillar uses between ten and twenty needles to form a tube or hollow tunnel.

This past week, for the sake of science and understanding, of course, a friend and I split a tube open to see if anyone was home. Indeed, we had our first view of the tiny caterpillar, which looked like it had an even tinier aphid atop it.

And then one day later in the week, I happened to spot some action at the tip of a tube. The caterpillars move up and down their silk-lined tunnels to feed on needles at the tip.

And once I spotted that, no pine has gone unnoticed. Much to my delight, I discovered a few more active caterpillars today.

One even honored me by demonstrating how it sews the needles to fasten them to the structure.

Back and forth it moved, excreting silk that formed a ladder-like web. When the time comes, the caterpillar will create another tube and do the same thing until it is ready to pupate overwinter.

The moth will emerge in April, when I’ll need to pay attention again. Two generations occur each year and those that overwinter are the second generation.

So now that you know, see if you can find a tube. Maybe you’ll be lucky as well and will get to see the caterpillar. It is only about one third of an inch long, so you’ll really have to look for a wee bit of movement at the tip of the tube. What I learned is that if I went in close with a loupe, it retreated.

This is certainly not just another tube left in the woods–now you know that these are the homes of the native Pine Tube Moths, who fortunately, are not considered a significant pest.