EFFECT OF THE RAT TAPEWORM, HYMENOLEPIS-DIMINUTA, ON THE COPROPHAGIC ACTIVITY OF ITS INTERMEDIATE HOST, TRIBOLIUM-CONFUSUM

Populations of Tribolium confusum that had been fed continuously (satiated) or starved for 48 h were separated into groups of 10 beetles each. Each group was placed in a test arena (diameter 90 mm) that contained two infective baits (feces from rats infected with patent Hymenolepis diminuta) and two baits from uninfected rats and allowed to forage for 120 or 240 min. The number of beetles aggregated in the immediate region of each bait was recorded every 20 min until the experiment was terminated. During the first 180 min the distribution of the beetles in the starved populations invariably favoured (P < 0.025) the infective baits. A similar trend was observed with satiated beetles but the difference in beetle distribution was significant (P < 0.001) only at the 100-min observation time. With both starved and satiated populations the differences in distribution between bait types were not significant after 180 min.