Lasius latipes

And the last picture is a close-up of an ant that is amber-colored crawling on a rock.

The caption reads, Citronella Ant.

It was around this time that he became fascinated specifically with ants.

The tiny creatures would focus his career, serve as a model for much of his work, and be the topic of his Pulitzer Prize-winning book, The Ants.

He co-authored the monumental work while a biology professor at Harvard University in Massachusetts with his friend and colleague, Bert Holdelbler.

All it took was a spark.

In this case, it was a simple walk in the woods, the peeling back of some bark, and the appearance of a seething mass of citronella ants, a type of common ant.

Thirty years later, in his Harvard laboratory, Wilson would discover how these ants secrete the chemical citronella and use it to attack enemies and spread alarm throughout the colony.