Hymenolepis diminuta: Effects of decerebration on thermal response behavior

Hymenolepis diminuta propels itself with unidirectional peristaltic-like waveforms. When intact adult H. diminuta are placed in a thermal gradient, with the anterior proglottids hot relative to the posterior proglottids, the worms migrate up the gradient toward the hot side. When the anterior is cold, relative to the posterior, the worms moved slightly or little. These behaviors in a thermal gradient represent true thermokinetic responses for an organism with unidirectional locomotion. Removal of the scolex, containing the worm's cerebral ganglia, did not significantly alter these thermal responses. These data suggest that the peripheral nervous system is capable of integrating sensory input over the length of the strobila and coordinating locomotory behavior, in the absence of the central nervous system.