They show up on seismic readings, if you're nearby enough, and can be attracted by drumming on the ground, if you can hit it with something sufficiently massive or noisy, particularly if it's rhythmically repeating, which annoys them. They're real easy to find, even so, because of the highly visible effect their nests have on the landscape.

But in this case, Shepard would probably be calling Julie for an assist on a situation already in progress, since the waking-side team is, to put it mildly... a little tiny bit underpowered, for the task at hand.

So she really would be a strong deciding factor, in this concept of the fight.