Camponotus (Tanaemyrmex) compressus is a common species in South Asia. Its natural range includes Bangladesh, India, the Maldives, Nepal, Pakistan, and Sri Lanka, and due to human activity, it has managed to settle in parts of East Asia and Africa. Here, we provide the first record of C. compressus from Sofia, where we found and collected a group of specimens. We determine the probability that they will successfully "integrate" into the country and adapt to our climatic areas, even in the presence of a queen (as was not established), which is very unlikely. However, we do not rule out such a possibility because of global climate change. The subgenus Tanaemyrmex, in which C. compressus is also classified, has four representatives that can be found in Bulgaria. These are C. aethiops, C. ionius, C. samius, and C. universitatus. The most common is C. aethiops, which is found in almost all xerothermic meadows and pastures, where it can often be seen collecting honeydew from aphids on plants. The other three species also prefer warmer habitats but have a limited range in the country.

Currently, there are two established alien ant species in Bulgaria. The Argentine ant Linepithema humile (Dolichoderinae) has a South American origin but can be found on every continent (except Antarctica). In Bulgaria, L. humile has been reported in Sofia, Varna, and Burgas. The pharaoh ant Monomorium pharaonis (Myrmicinae) can be defined as a synanthropic species. It has spread all over the world and mainly inhabits factories, hospitals, and homes. In the tropics, it can also nest outside buildings. In Bulgaria, M. pharaonis has been reported in Ruse, Shumen, Sofia, Svilengrad, Plovdiv, Malko Tarnovo, Varna, Obzor, Tsarevo, Burgas, Sozopol, and Ahtopol. This study is a part of the project under grant contract number KP-06-N61/6 – 14.12.2022.