About a year and a half ago, I used this space (”Annelidanger,” 4/21/2004) to raise awareness about an insidious problem on the Cornell campus - namely the way that worms slither onto the sidewalk in the rain and are, for lack of a better term, totally gross. Though an Ad Hoc Committee on Worm Welfare has yet to be assembled, I have been satisfied with the public response and, for 19 months, I have laid down my arms against a sea of squashed yucky things.

But now I must take them up again.

If you’ve been on the Arts Quad, you’ve probably noticed them. They blanket the sidewalk that runs north-south in front of Stone Row (Morrill, McGraw and White Halls) in numbers never seen before, quantities too staggering to believe. Thousands of caterpillars darken the cement, flattened by the treads of unsuspecting undergrads and gallivanting grad students. And at night — oh, the scene! — the sidewalk lives with the teeming, wriggling bodies of thousands more. It’s positively fulsome.

I was eager to get to the bottom of this caterpillar conundrum, so I visited the website of the Cornell Entomology Department (http://www.entomology.cornell.edu). After perusing the faculty list and attempting to determine which professor’s specialization would be most germane to the issue at hand (Semiochemical development? Systematics of coleoptera?), and briefly considering closing my eyes and pointing to a name at random, I opted for the one faculty member whose profile I could understand: Professor Ann E. Hajek, who specializes in “biological control and population ecology.” Professor Hajek was kind enough to answer my questions about the caterpillars, and I am privileged to be able to pass the information on to you.

The caterpillars are the larvae of a species of moth called the Large Yellow Underwing, so named because of the bright yellow color of the hindwings, visible during flight. The caterpillars are one of a group of species known as “cutworms,” which feed on the roots and bases of plants. As you can imagine, this isn’t very good for the plants, which explains why the grass in front of Stone Row is nearly all dead.

So why haven’t we seen them before? Because they haven’t been here before, at least not in such huge numbers. The Large Yellow Underwings were introduced to Nova Scotia from Europe in 1979, and they’ve been moving steadily southward ever since. Though the first specimens in the Cornell collection were discovered in 1997, this is the first outbreak. Because the moths are non-native, there are not yet any predators or parasites that feed upon them. Without any population checks, the moths are reproducing with abandon — a single moth lays approximately 500 eggs, according to Hajek — and although the grounds crew has sprayed the area with insecticide, there’s no telling how effective this will be in the long run.

The U.S. doesn’t have a great past with non-native invasive species. The most famous historical example is that of the common starling, which was introduced to Central Park in the late 1800s in an effort to fill the park with all of the types of birds mentioned in Shakespeare’s plays. A population of less than 100 steadily grew into a population of 200 million spread across the country, with flocks so huge that they block out the sun as they fly by. Native species have lost nesting sites and food sources to the burgeoning starling population. (Oops.)

This doesn’t bode well for Ithaca and the Large Yellow Underwings. It’s likely that they’ll be back next year, and every year after that; in fact, future generations may be even more successful, because the drought this past summer decimated much of the plant life that cutworms typically eat. Are we destined for another “starling incident,” with millions of moths darkening the skies as they voraciously descend upon crops? Probably not, says Hajek, but “people will see a lot of them around lights on their way home from drinking in Collegetown at night.”

Okay, fair enough, but let’s be honest with ourselves: we students don’t really care about Ithaca’s ecology, or whether the plant life will suffer. What we care about is the fact that it’s now impossible to walk from Uris Library to White Hall without stepping on a hundred bugs (which, incidentally, is barely making a dent in the population). It’s unsettling and, frankly, pretty disgusting. So I wondered, what does an entomologist — someone who has devoted her entire career to the study of insects — think about the blitheness with which students grind the cutworms into the pavement? “I think students could feel fine about stepping on them,” Hajek replied, “but they are big and squishy, so they might want to prepare for that.”