More than 16,000 ticks have arrived in Nate Nieto’s mailbox. He’s an associate professor of microbiology at Northern Arizona University, and he launched a citizen science project to learn more about the diseases ticks can transmit. People from 49 states sent him (and his collaborators at Colorado State University) the ticks they found on themselves or other people or dogs. “We started thinking that the majority of tick awareness is really in the Northeast and the Upper Midwest, and so really