This article was originally published by Knowable Magazine. Haldre Rogers’s entry into ecology came via the sort of man-made calamity that scientists euphemistically call an “accidental experiment.” She’d taken a job in 2002 on the Pacific island of Guam and the neighboring Mariana Islands to study the invasive brown tree snakes that were introduced to Guam, likely from a cargo ship, shortly after World War II. In the ensuing decades, these large snakes thrived, obliterating many native animals. Rogers’s initial task was to track reported sightings on nearby islands. The job, she says, “gave me lots of time to just stare at trees, trying to see snakes. And I realized that, ‘Oh, there’s actually all of these differences between forests on Guam and forests on other islands.’” And so, for her Ph.D. dissertation, Rogers decided to address whether the snakes themselves had changed Guam’s trees and shrubs. The potential link was this: Many trees and other plants rely on animals to disperse their seeds—and that’s often achieved through fruit. Like mini ecological Trojan horses, fruit …