Carrie Arnold

This article was originally published by Quanta Magazine.Thousands of miles from home in the steamy Amazon rainforest in the mid-1800s, the British naturalist Henry Walter Bates had a problem. More than one, really: There were thumb-size biting insects, the ever-present threat of malaria, venomous snakes, and mold and mildew that threatened to overtake his precious specimens before they could be shipped back to England. But the nagging scientific problem that bothered him involved butterflies.

Originating in the Great Dismal Swamp of Virginia, just south of the Chesapeake Bay, the Elizabeth River is turbid and brackish, its banks redolent with the nose-wrinkling stench of rotting vegetation. These muddy, pungent waters support an array of life—oak and maple trees, herons, otters, and oysters.