Hymenolepis diminuta: circadian rhythm in movement and body length in the rat

The relationship between the ingestion by rats feeding ad libitum under normal laboratory conditions and the positions of mature Hymenolepis diminuta was investigated using 4 to 10 month SPF-CFE rats with single-worm infections.The quantity of food consumed in ten sessions during the 24 hr was determined. Feeding behavior was similar for both sexes, whether or not infected and showed a marked nocturnal preference.The positions of the scolices and terminal proglottids were determined by regular sequential sampling and showed two movements, change in body length and movement along the intestine. These movements were not exhibited by worms in starved rats, thus they appear to be dependent upon the passage of nutrients along the intestine.