Predictability of morphological gradients in the tapeworm, Hymenolepis diminuta.

The strobila of an adult tapeworm represents a continual gradient of developmental stages from immature to gravid proglottids. The purpose of this study was to determine if organogenesis (as measured by the developmental gradient) in tapeworms within a single host and among different hosts occurred at the same rates. Rats were infected with Hymenolepis diminuta and the tapeworms were recovered 20 days post-infection. The total number of proglottids in each worm was determined, and five 'benchmarks' of organogenesis were quantified. The data demonstrated that organogenesis in worms from a single host occurred at a relatively constant rate, but that rates in tapeworms from different hosts were different.