On remote detection of odors by insects.
As a twelve year old interested in nature, I really wanted to see a live Polyphemus moth. They are very large and beautiful. I had only seen preserved in specimens in insect collections.
One year, in the Fall, I found a cocoon on a branch in the woods, brought it home, propped it in a vase on my desk. The following Spring, it hatched one night when I was asleep. When I woke, there she was, my long sought Polyphemus.
It was clinging to the screen over my open window. When I went closer, I saw that there were three of them! How? I knew only one could emerge from a cocoon. Then I noticed: One inside the screen and two outside.
A little research gave me the answer. A female Polyphemus releases a pheromone that the males can detect from up to six miles away! They will fly directly to her to mate and she will lay eggs the same day.
The amount of the pheromone is infinitesimal, about one billionth of a gram. Still, that amounts to a few hundred molecules. But six miles!
Life will find a way.
[I let her go, of course.]