| Abstract [eng] |
The aim of the study is to evaluate behaviour of medicinal juvenile leeches (Hirudo verbana) by composing aggregation, establishing changes in aggregation during effect of time also applying thermic and light stimulus. During investigation of juvenile leeches behaviour from leaving the cocoon to first feeding, first aim was to observe juvenile leeches which has just left the cocoon bearing in mind that leeches cannot be moved into water. Characteristics of this observation were 100% groups’ aggregation. Moving juvenile into the water for a short period of time due to mechanical effect, aggregations separate fast after 31,25±0.752 min. Observation concludes, that both large and small density groups have a tendency to show intense aggregations and with time aggregations starts to separate. Comparing these groups it was determined that after 1 day since hatching, significant effect was not achieved between these groups, but after 3 days significant effect have been achieved. In addition, group aggregation difference was observed before and after feeding. Achievement was that statistical difference was accurate disputing density groups. Experiments showed that aggregation intensity in groups were composed out of juvenile leeches that were in the cocoon and groups that were composed out of different cocoons were statistically unreliable. 640-670lx illumination strongly affected leeches and they composed intense aggregations. Results showed that results between experimental and control groups were reliable. This again shows the fact that illumination does a negative effect on medicinal leeches which during illumination goes into defensive response. During an experiment with thermal effect on juvenile medical leeches, average temperature and point when aggregations start to disappear was determined. During effect with low temperature juvenile leeches creates aggregations, but these results are statistically unreliable. In conclusion, the formation of aggregations is an informative and important indication while investigating juvenile medicinal leeches. These results can be relied on during further investigations and applying to ecotoxicological experiments. |
