Plume


One molecule.

That's enough. One molecule adrift in thirty thousand cubic meters of dark, and seventeen
thousand hairs on the left antenna adjust simultaneously. The signal writes itself in a
register that has no word for signal.

Wind: northeast.

He turns into it.


Three. A thread.

What the moth has instead of sight: gradient, absence, the plume — a chemical message
written in degrees of more and less. More means: this direction. Less means: cast wider,
start again. The wings are not how he navigates. The wings are what happens between one
scent-hit and the next.

He casts wide. Finds it again. Tightens.


Closer now. A wall.

Beneath the pheromone, the air brings: last week's rain in the soil, a chrysalis already
emptied, the rust-smell of something's casing. These aren't words. These are shapes arriving
in a part of the nervous system that exists below decision. He registers them and they mean:
not her. He keeps moving.


Then—

In a different channel — not smell, not wind, not antenna — a pulse. Forty-three kilohertz.
Forty-seven.

The wings tip.

No decision. The body knows that frequency the way skin knows fire. The wings tip and the
body spirals out of the beam, out of the echo, into the interval where the bat's world
doesn't include him.

He doesn't know he was afraid.

He's in the air. The plume is to the left, and slightly upwind.


He turns.


One molecule.

Still enough.