An experimental study of the survival characteristics, activity and energy reserves of the hexacanths of Hymenolepis diminuta

Similar survival characteristics were demonstrated for hexacanths of Hymenolepis diminuta incubated in Tyrode's solution with or without a glucose supplement (0-50 mg/ml). The survival rate of hexacanths in all media tested was shown to be age-dependent and led to a maximum life-span of approximately 11 h. The amount of energy reserves, as measured by microdensitometric determination of PAS+ material, declined rapidly in time to a plateau at approximately 8 h. Residual PAS+ matter present beyond that period was interpreted as structural and thus non-utilizable material. The rate of activity as measured by hook movements declined more rapidly, and continuous hook cycles were rarely observed after 2 h and ceased after 4 h. A close correlation was demonstrated between the decline in PAS+ material and the total number of hook cycles completed per unit of time. The quantitative results on survival, energy reserves and activity are discussed in relation to the penetration of hexacanths into the haemocoele of the intermediate host.