Range expansion of assassin bug (Peirates hybridus) (Hemiptera: Heteroptera: Reduviidae) in the Czech Republic

Abstract

The distribution of the rare assassin bug (Peirates hybridus) in the Czech Republic underwent significant changes during the 20th and 21st centuries. The species disappeared from the territory in the mid20th century, but has recently recolonised it and rapidly spread be yond its original range. The species was rediscovered in Moravia after 50 years (in 1998), and after more than 100 years also in Bohemia (in 2021). At the start of the 21st century, it rapidly spread through the valleys of large rivers and into previously inhabited areas. The expansion of the species is likely due to a combination of factors related to climate change. Historically, P. hybridus was found in naturally rich xerothermic habitats. Today, the bug is commonly found also in open rud eral habitats or sparse forests. It shares these habitats often with several threatened species. Appropriate management, such as mosaic mowing, grazing, cut ting of woody plants, and regulated trampling by hik ers or heavy equipment operation, can support not only the assassin bug but also other endangered spe cies. Considering the dynamic pattern of change in the northern boundary of the site over the last century, it is recommended to monitor its distribution in the future. Given the current rate of species expansion, we pro pose that the species' threat category be downgraded from Critically Endangered to a lower level, or even re move from the Red List if expansion continues.