Alien ants spreading through Europe: Brachyponera chinensis and Nylanderia vividula in Italy

Abstract

The number of known alien ant species throughout Europe has been steadily increasing during the last few decades and Italy has been no exception, with four new taxa reported in the last five years. Here, we document new data on the Asian needle ant Brachyponera chinensis (Emery, 1895), an invasive alien species whose first establishment in Europe was detected in the southern Italian city of Naples in 2022 and which has now been found near Lake Como in northern Italy, representing the second European record, about 730 km distant from the first. Furthermore, we report for the first time the presence of Nylanderia vividula (Nylander, 1846) in the country, based on specimens collected both in Rome and near Lake Como. This is at least the second Nylanderia species established in the country after N. jaegerskioeldi, first reported in 2018. Unlike B. chinensis, N. vividula is not considered an ecological and health threat in the invaded range and is already known to occur in several other European countries. While only a few introduced ants in Europe are considered serious ecological, economic or health threats, the increasing circulation of several alien species and the poor ability to swiftly track their movements and detect their establishment can render management very difficult.