Darko is interested in the study of the historical processes that create biodiversity, particularly in conditions of isolation. His main study group are spiders and other invertebrates present around the Pacific Ocean, with special attention to volcanic archipelagos and the Gondwanic landmasses. He combines field and museum work with phylogenetics, population genetics and genomics. He is also interested in biodiversity discovery: species inventories, species descriptions and natural history observations. He teaches courses about Zoology and Evolution, and has participated in several field courses with the Organization for Tropical Studies.