When I think of Geneva, Switzerland in 1740, I do not think of aphid reproduction. Lucky for us, one 19-year-old Charles Bonnet, decided to abandon his law studies and spend his time trying to solve the mystery of aphid reproduction. Despite 70 years of investigations and experiments, no one had ever seen a male aphid or aphids in the act of mating. Aphids are small creatures and, in the 18th century, could also outwit any number of naturalists. Charles Bonnet was the last of them.

   The story of Bonnet's Major Discovery is recounted in Rebecca Stott'sDarwin's Ghosts--a must read for accidental and intentional naturalists interested in the well-told, impeccably researched story of the collective discovery of evolution. "Darwin's" theory of evolution, according to Stott, should be attributed to many other thinkers--from Aristotle, Jahiz, Leonardo da Vinci, Denis Diderot, Alfred Wallace, and other lesser known philosopher-naturalist-scientists such as Charles Bonnet. Here is how he earned a place in Stott's history:

  On May 20, 1740, he "placed a single newborn aphid on a branch inside a glass flask sunk in a container full of earth. His task was to guard and testify to her virginity." Bonnet watched the flask "through every hour of the day" and, by June 1, the imprisoned female had molted a few times and had given birth. Over the next 23 days, she produced 94 more aphids. Through repeated experiments and careful documentation, Bonnet was the first human to record proof of a form of sexual reproduction, now called parthenogenesis, that requires no fertilization by the male.

   At this same time, Bonnet's uncle, Abraham Trembley, was studying the reproduction of moths and plant-like animals known polyps (and now called hydra) on the outskirts of The Hague. Trembley discovered that no matter how many times or ways he cut the polyp, the original part lived and the cut part sprouted to life. This spontaneous regeneration was greeted with skepticism and fear in scientific societies at the time. The polyps' ability to self-regenerate and the aphids ability to reproduce asexually cast doubt on the widely held belief that reproduction of living things was "naturally" sexual and that God controlled the miracle and design of life. These discoveries, seemingly to the contrary, raised uncomfortable and challenging questions about the "system of souls in animals." When a polyp was cut into infinite parts, for example, where was its soul?

  Charles Bonnet wrote an impassioned letter to one of his professors, Gabriel Cramer, expressing his concern that the aphids, polyps, moths, and therefore all insects would be "degraded" to soulless machines as   the natural world was shown to be increasingly incomprehensible and indecipherable. Cramer wrote back:

   "Let me breathe a little" he replied. "You are overwhelming us with marvels."