Research of butterflies and moths, including other insects on the territory of the Republic of Serbia requires time, a systematic approach and commitment to work. Many entomologists whose research preceded the present one possessed these and many other qualities. Lepidoptera as a group of insects are central in many ecosystems, from forests and farmlands to urban environments. The paper presents a total of eight research objectives for the lepidopteran fauna in the Republic of Serbia and describes how they were achieved. Species causing damage to agricultural production are identified as economically important, and their importance and possible dispersal pathways, which are closely related to climatic conditions, are described. Climatic changes affect the movement and dispersal of butterflies and moths in a given area, but at the same time they affect the dynamics of their occurrence and the size of populations. Therefore, faunistic research tracks changes in environmental conditions. When forecasting the occurrence of certain butterfly and/or moth species, it is difficult to predict the movement direction of migratory species, which is why the list of migratory species is an integral part of this work.