Gnathotrichus materiarius is listed as an alien ambrosia beetle in European fauna. This is an invasive species from North America, which was found in Europe (France) in the 1930s. In Poland, it was recorded in 2015. Already in 2017 numerous infestations of G. materiarius on lying Pinus sylvestris wood were obsereved. G. materairius is a xylomycophagous species and wood damage to its feeding is similar to that caused by striped ambrosia beetle Trypodendron lineatum. The paper presents sites of G. materairius occurrence found in 2016 and 2017. These include 15 sites located in managed forests (5 forest districts) as well as in 2 national parks situated along south-western border of Poland. G. materairius beetles were found in pheromone-baited traps used to monitor Ips duplicatus and I. amitinus or collected from infested Scots pine wood. The paper presents the description and characteristics of wood damage due to G. materiarius as well as its distinguishing features.

Gnathotrichus materiarius (Fitch, 1858) is an alien species in the European fauna. In Poland, this species has not been recorded thus far, although it was assumed that it may be present. This paper presents the fi rst site of G. materiarius in Poland. A single individual of the beetle was captured during monitoring activities of the Double-spined bark beetle -Ips duplicatus (Sahlb.) in the pheromone traps with ID Ecolure pheromone in the Kamienna Góra Forest District, Krzeszów forest circle. Selected aspects of this species' ecology in the European conditions were discussed: capturing of Double-spined bark beetles in pheromone traps intended for various coniferous tree bark beetles, species' low count, possibility of the presence of two generations in one season and vertical distribution at various heights above sea level.