Activity of flour beetles (Tribolium confusum) in the presence of feces from rats infected with rat tapeworm (Hymenolepis diminuta)

Abstract

We studied the attraction of flour beetles (Tribolium confusum) to feces from rats infected with the rat tapeworm, Hymenolepis diminuta. Beetles were either fed or fasted prior to each trial. During trials, beetles were tested singly or in groups and offered a choice (i) between natural baits made from fecal pellets from infected and uninfected rats or (ii) between artificial baits made from feces of uninfected rats and differing only in the presence or absence of tapeworm tissue. Fasted beetles had a strong nonspecific attraction to baits, while fed beetles tended to avoid baits. Fasted beetles also exhibited a greater ability to discriminate between control and infective baits, sometimes preferring infective baits but at other times avoiding them. Experiments with artificial baits show that at least some of the signals which beetles respond to are of parasite origin. The results suggest that the foraging behavior of beetles in the presence of rat feces is more complex than previously thought and includes the phenomena of attraction to and avoidance of feces from infected rats in situations whose parameters have yet to be identified conclusively.