[The effect of crowding tapeworms Hymenolepis diminuta based on proglottids in the period of intensified variability].

Tapeworms obtained 13 months after the administration to rats of cysticercoids Hymenolepis diminuta - WMS il1 measured in 3-6-specimen populations an average of 677.9 mm in length while in 23-26-specimen populations an average of 356.9 mm in length. Strobilas of an exclusively unilateral (right-sided) position of genital pores (PGP) appeared in 76.3%-79.8% of tapeworms of the investigated groups. In such tapeworms belonging to 23-26-specimen populations the frequency of occurrence of typical proglottids containing 1 testis on the poral side and 2 testes on the aporal side (1p2a) and type 0p3a proglottids averaging 86.5% and 6.8%, respectively, declines in comparison to the average frequency of occurrence of proglottids of this type in 3-6-specimen populations amounting to 87.8% and 8.8%, respectively. The frequency of occurrence of four-testes (1p3a) proglottids averaged 5.5% in tapeworms from the 23-26-specimen populations and was 4.0% higher than the 1.5% average in tapeworms from the 3-6-specimen populations, in spite of the fact that in a population with a higher number of specimens proglottids are smaller and, therefore, have less room for an additional number of these organs. In tapeworms with variable PGP type 2p1a proglottids constituted the most frequent deviation in each of investigated group of different infection intensity. Their average frequency of occurrence rose from 0.4%-0.5% in tapeworms with unilateral PGP to an average of 5.5%-5.9% in tapeworms with variable PGP. Close positive correlation was found in tapeworms with variable PGP between the frequency of occurrence of such changes and the frequency occurrence of type 2p1a proglottids in every of investigated group (P < 0.01, r = from +0.887, to +0.918).