The data on new findings of rare and noteworthy insect species in Karelia are presented, including species new for the regional and East Fennoscandian fauna. These findings chiefly come from southern part of Karelia. These insect species can be divided into two groups: the first one includes species belonging to poorly studied orders, and the other one comprises species non-native in the republic. The expansion of some of these species has been induced by human impact, whereas a majority of other species probably appeared in Karelia through natural areal expansion. The possible reasons for the recent changes in the region's insect fauna are discussed. The enrichment of the species composition takes place mostly due to northwards movement of southern species, presumably as a result of a rise in average annual temperature. Examples of insect species with northwards expanding population ranges are provided. There are how ever some factors that negatively influence the species diversity of insects: these are changes in the environment, primarily human-induced, not related to climate change. Climate warming may induce alterations not only in the species composition, but also in the population dynamics of insects. An example provided here is the European spruce bark beetle, which has lately been demonstrating massive outbreaks in Karelia, which is a new phenomenon in the region. The importance of Karelian territory as a corridor for the insects northwards and north-westwards dispersal during the postglacial period and current trends in the temporal dynamics of the regional entomofauna are emphasized.