After having changed his focus to leaf-cutter ants, he attended an ecological conference and met Dr. J. Malcolm Cherett, a specialist in leaf-cutter ants from the University of Wales, Bangor, U.K. By this chance meeting, Heraldo ended up much farther away from the rainforest than Sao Paulo ever was, as he entered the PhD program at that University of Wales and spent the next year taking classes toward his degree. After the classwork was finished, Heraldo returned to Manaus, and INPA, to complete his dissertation and obtain his doctoral degree.

Heraldo has been at INPA now for 14 years, and is currently both a ecological researcher as well as the head of the Department of Ecology. Though still interested in the leaf-cutter ants, Heraldo has broadened his research to cover not only single ant species but also the interaction of different species of ants in the forest. A typical study includes laying bait on the forest floor, and then documenting the numbers and types of ants who are attracted to the bait and how the different types of ants react to each other, whether they fight or else avoid each other. He also observes how different ant species communicate knowledge of the bait to their own nestmates. (See Program 1 for a documentary sequence showing Heraldo at work.)