About regeneration of alien polychaete Polydora websteri (Annelida: Spionidae).
New data have been obtained on the regenerative capacity of the invading polychaete Polydora websteri Hartman in Loosanoff & Engle, 1943. The material was collected in 2019-2020 in the area of Sevastopol. Polychaetes were extracted from blisters in the valves of an exotic Black Sea oyster species-Crassostrea gigas (Thunberg, 1793). The mollusks were grown on an oyster farm. Polychaetes were kept in aquariums with filtered seawater at a temperature from 8.8 to 25.8°C and a salinity of 17.5-17.8‰. Under laboratory conditions, body segments were removed from the worms and their recovery was observed. It was found that P. websteri regenerated both the anterior and posterior parts of the body. The minimum number of segments capable of simultaneously restoring both anterior and posterior regions is three mid-body segments. The regeneration process in P. websteri depends significantly on the water temperature. In the range of 8.8-26°C, a direct relationship was established between the water temperature and the number of regenerated specimens. An inverse relationship was found between the water temperature and the time spent on regenerating the lost fragments. When water was warmed up, the proportion of regenerated P. websteri increased from 15 to 87%, and the duration of regeneration decreased by 2.5 times.