engleski

Predation in turbellarians: Dugesia gonocephala as superior predator - preliminary observations

Turbellarians (flatworms, Platyhelminthes) in freshwater or moist terrestrial environments are mainly predatory species. In these experimental setups, we assessed interaction between turbellarians Dugesia gonocephala (Duges, 1830) and Polycelis felina (Dalyell, 1814) in terms of their competitive capability. In ex situ microcosms experiment turbellarians were exposed through the day-night rhythm to different temperature and light conditions: 25 °C and 8 h light, 13.5 °C and 16 h dark, respectively. The results were recorded immediately and every 1, 8 and 24 h after the beginning of the experiment. Five replicas with both fed and starved animals were set up. Species D. gonocephala, in both conditions of temperature and light, attacked and preyed upon P. felina and took over pigmentation from P. felina considering that P. felina is black colored and D. gonocephala is grey transparent. There was no reverse process recorded. Moreover, it was noticed that previously fed D. gonocephala specimens more likely attacked P. felina than starved individuals did. Also, the higher rate of predation was present at higher temperature (25 °C) than under the conditions of lower temperature (13.5 °C). Generally, when turbellarians were put in microcosm at the beginning of the experiment, they were very agile searching for prey. Afterwards, D. gonocephala and P. felina rested mostly on the opposite sides of microcosms. Results of our study indicated new insights into predation among turbellarians and more information about freshwater micro-ecosystem food competition.

turbellarians ; hydra ; predation ; microcosm

ISSN 2459-8402.