RESUMEN
ABSTRACT The limited knowledge of biodiversity constrains conservation strategies in a wide range of questions. Overcoming and recognizing these knowledge deficits require integrated efforts by current researchers and constitute crucial challenges for the next generations. Prof. Dr. Claudio Froehlich was a pioneer in implementing a research program integrating ecology and taxonomy, especially in aquatic insects, in Brazil. This special issue was conceptualized to honor his prolific scientific career and constitutes a tribute to the pioneering in Brazilian aquatic entomology. A brief biography of Prof. Dr. Claudio Froehlich was presented as well as 13 papers facing the biodiversity knowledge shortfalls from five insect orders (Diptera, Ephemeroptera, Neuroptera, Plecoptera, Trichoptera), with behavior reports (Eltonian shortfall), 23 new species described (Linnean shortfall), and distribution records for several taxa (Wallacean shortfall).