This study focused on bionomics of the ash bark beetle Hylesinus fraxini (Panzer 1779). The study area was at Jílové u Prahy in the Central Bohemian Region of the Czech Republic. In February 2014, three common ash (Fraxinus excelsior) trees were felled and Hylesinus fraxini infestation was subsequently observed from March. Beetles were collected from 20 debarked logs and dissected under stereomicroscope, and their sex was determined. Five logs with bark beetles were placed into photoeclectors. Beetles that emerged were collected and put into the second photoeclector with fresh ash wood to determine whether they would establish the second generation. The analysis showed that each gallery system with a pair of bark beetles contained one male with only one female. If one adult of H. fraxini was found in the gallery system, it was usually female. Therefore, possible polygamy of Hylesinus fraxini was not confirmed in Central Bohemia. Maternal gallery length significantly correlated with the number of eggs laid per female. Offspring beetles did not establish the second generation, as only maturation feeding occurred in fresh wood.
