[Effect of procercoids of Triaenophorus nodulosus on the biology of their 1st imtermediate hosts Cyclops strenuus].

The effect of procercoids of T. nodulosus on the periods of metamorphosis, fecundity, survival and the capacity to infect C. strenuus at all copepodid stages (I-V) was studied experimentally. It has been first shown that early copepodid stages (I-III) can be easily infected and serve as first intermediate hosts of T. nodulosus. Under the effect of the parasite the metamorphosis periods of the I and 2-nd copepodid stages increase considerably even at the low infection intensity while at the IV and V copepodid stages--only at the high infection intensity. If the infection takes place at the IV copepodid stage the female fecundity decreases even at a high infection intensity. The life span of infected and noninfected cyclops coincides. At early developmental stages the relations in the system "T. nodulosus-C. strenuus" manifest themselves in different ways and result in the breach of the important biological function of the host.