On October 5, 2015, the latest cohort of graduates from the Museum’s Richard Gilder Graduate School—the first Ph.D.-degree-granting program for any museum in the Western Hemisphere—will receive Doctor of Philosophy degrees in Comparative Biology at a commencement ceremony in the Milstein Hall of Ocean Life. We're profiling the soon-to-be-minted Ph.D.s in the weeks leading up to commencement, and today we introduce Phil Barden.
Growing up in the Southwest, Phil Barden was always intrigued by animals, spending his free time “doing kid stuff,” like catching snakes and lizards. But in high school, when he mentioned his interest in nature to a guidance counselor, the man discouraged him. “Naturalists,” he said, “don’t exist anymore.” They were from “olden times,” an extinct species.
Despite this pessimistic counsel, Barden remained determined to find a way to study nature. In college at Arizona State University, he worked in a biology lab where the researchers studied eusociality, a trait of some animal groups, including insects like bees and ants, wherein most individuals forego reproduction for the benefit of the greater community. In many ant colonies, for example, there is just one queen; the workers are generally sterile females, while males emerge only briefly to mate with fertile virgin queens before dying soon after.
The more Barden learned about the lives of ants, the more fascinated he became. There are over 13,000 known species of these insects, Barden notes, and their lifestyles and adaptations are wildly diverse. Some types are vegetarian, while others might dine only on one type of millipede.
Likewise, certain ant species have co-evolved with a single plant species, living in a mutually beneficial symbiosis: the ants may help spread the plant’s seeds or patrol the plants, biting and swarming would-be predators to keep their plant home and food source healthy.
During his four years at RGGS, Barden focused on study of ancient ant species. The early evolution of ants is poorly understood, and Barden and his advisor, David Grimaldi, wanted to find out more. Were early ants social or solitary animals, for instance? And from what lineage of ancient ants did the vast array of modern ant groups evolve?
Early on, Barden traveled with Grimaldi on an expedition to a lignite coal mine in Gujarat, India, to dig for ants fossilized in amber. Lignite is a type of soft coal composed of fossilized plant and other organic material, with seams of fossilized tree resin, or amber, running through it. As the miners worked, the scientists used pick-axes to excavate the amber, which dated to about 50 million years ago.
About that same time, however, a tantalizing find arrived at the Museum. A collector loaned the institution specimens of nearly 100-million-year-old Burmese amber. Enclosed within these specimens were some of the oldest ant fossils known!
These extraordinary specimens suddenly took priority for Barden, who spent much of his time at RGGS—when he wasn’t taking classes or teaching—analyzing the ants within. Using CT scanners from the Museum, Cornell University, and the University of Texas, as well as highly magnified x-ray images from the synchrotron at Argonne National Laboratory, Barden and Grimaldi described a dozen new species of fossil ants.
Barden also generated an evolutionary tree of ants that incorporates these important ancient fossils, and he made key new insights into the early history of ants and the evolution of sociality. That work forms a core part of his doctoral dissertation, which will be published next year.
Today, Barden works in the lab of Professor Jessica Ware at Rutgers University Newark, where he recently began a two-year National Science Foundation Postdoctoral Research Fellowship. There, he aims to further advance his reconstructions of the evolution of ants, integrating both fossil and DNA evidence. And he’ll finally have the time to analyze the 50-million-year-old amber fossils he collected in Gujarat, India, but never had the chance to investigate. What can ancient ants tell us about the world today? With his fossil discoveries and novel research approaches, Barden is finding out.