The influence of the planting time and conditions on the reproductive properties of Hirudo verbana and Hirudo medicinalis.

Factors that affect on the sexual behavior of leeches not only in nature, but also in artificial conditions remain largely unexplored. We did not find data on the behavior of medicinal leeches, which are not placed in time from the aquatic environment in the peat-soil conditions after the appearance of clitella on their bodies. Therefore, the study of this problem has become relevant. For the study, four experimental animals groups were formed: 1 control - medicinal leeches (H. verbana), which were allowed to breed immediately after the appearance of clitella; 2 experimental - medicinal leeches (H. verbana), which were kept in an aqueous medium after the appearance of clitella for a month and then allowed to breed; 3 control - medicinal leeches (H. medicinalis), which were allowed to breed immediately after the appearance of clitella; 4 experimental - medicinal leeches (H. medicinalis), which were kept in an aqueous medium after the appearance of fertilization belts for a month then allowed to breed. The 400 sexually mature healthy medical leeches of two types aged 1.5-2 years were used in experiments. Initially, four individuals were placed into 4-liter containers for sexual intercourse, and after the appearance of differentiated fertilization zones, the control groups were immediately allowed to breed in a peat-soil environment. The experimental groups were left in the same containers for a month and then the survived leeches were allowed to breed. As a result of our research, we found mortality in the experimental groups. From the first week, we found that mortality before breeding of H. verbana was 15.6 ± 2.1% and of H. medicinalis - 14.3 ± 1.5%. Also, 92 ± 0.9% leeches from experimental group died in pet-soil environment sometimes even without cocoon deposition. The experimental group had defective cocoons, but mostly dead offspring.