BOTZ, J.T.*; LOUDON, C.; BARGER, J.B.; OLAFSEN, J.S.; STEEPLES, D.W.; University of Kansas; University of Kansas; University of Kansas; University of Kansas; University of Kansas: Slipping on sandy slopes–physical determinants of antlion pit function

The difficulty that insects have walking on inclined sand is used to advantage by antlions, which construct pits in sand for prey capture. The locomotion of ants, physical characteristics of sand, steepness of antlion pit walls, and sand-size preference of antlion larvae were evaluated using sand with distinct particle-diameter ranges. An ant’s probability of falling when walking on a sandy slope increased with increasing slope angle or decreasing sand-particle diameter. In each sand fraction, the steepness of pits constructed by antlions was the same as the angle of repose of the sand, and the angle of repose did not vary among the three coarser sand fractions but was significantly higher in the finest sand. Given a choice of all four sand fractions, antlion larvae preferentially built pits in the two finest ones.