Editing Angle of repose (section)

== Exploitation by antlion and wormlion (Vermileonidae) larvae ==
[[File:Antlion trap.jpg|thumb|280px|right|Sand pit trap of the antlion]]

The larvae of the [[antlion]]s and the unrelated wormlions [[Vermileonidae]] trap small insects such as ants by digging conical pits in loose sand, such that the slope of the walls is effectively at the critical angle of repose for the sand.<ref>
{{cite journal
 |last1=Botz |first1=J. T.
 |last2=Loudon |first2=C.
 |last3=Barger |first3=J. B.
 |last4=Olafsen |first4=J. S.
 |last5=Steeples |first5=D. W.
 |year=2003
 |title=Effects of slope and particle size on ant locomotion: Implications for choice of substrate by antlions
 |journal=[[Journal of the Kansas Entomological Society]]
 |volume=76 |issue=3 |pages=426–435
}}</ref> They achieve this by flinging the loose sand out of the pit and permitting the sand to settle at its critical angle of repose as it falls back. Thus, when a small insect, commonly an ant, blunders into the pit, its weight causes the sand to collapse below it, drawing the victim toward the center where the predator that dug the pit lies in wait under a thin layer of loose sand. The larva assists this process by vigorously flicking sand out from the center of the pit when it detects a disturbance. This undermines the pit walls and causes them to collapse toward the center. The sand that the larva flings also pelts the prey with loose rolling material that prevents it from getting any foothold on the easier slopes that the initial collapse of the slope has presented. The combined effect is to bring the prey down to within grasp of the larva, which then can inject venom and digestive fluids.