• defecation behavior;
  • hind-femur length;
  • Orthoptera;
  • Pyrgomorphidae;
  • sexual difference


Adults of the grasshopper Atractomorpha lata use a hind leg kick to project their frass a considerable distance from themselves. To clarify the defecation behavior quantitatively and collect basic information that aids in clarification of the adaptive significance of this behavior, we measured the flying distance of kicked frass and examined the factors affecting the flying distance in adult A. lata. Males and females kicked their frass an average of 252 and 487 mm away, respectively. This represented more than ten times the body length or 100 times the length of the frass pellet for either sex. Only sex affected the flying distance of frass. There were sexual differences in hind-femur length (females longer than males), volume of frass pellet (females larger than males) and ratio of diameter to length of frass pellet (RFP; larger in males than in females). The flying distance appears to be affected by the femur length, volume of frass pellet and RFP when data of both males and females were combined for analysis. However, none of these effects were observed when testing the effects within each sex. These results suggest that the sex difference in the flying distance does not result from the sex difference in femur length, volume of frass pellet or RFP. Because A. lata kicked their frass far away in both sexes, the frass-kicking behavior might give benefit common to both males and females.