Two theories exist to explain the arrangement of antlion pitfall traps when multiple larvae inhabit the same patch. Within a patch, the "donut theory" predicts antlions should move to the patch periphery, the spatial uniformity hypothesis predicts antlions should disperse evenly across the patch. A field study in Costa Rica using artificial pitfall traps demonstrated that traps in a donut array catch significantly more prey items than inside traps of a dispersed array. The field study and both theories assume that all prey items falling into a trap will be caught on the first encounter. Empirical studies determined that for the most common prey item the initial capture probability is 17%, and capture probability rises after an initial encounter. Computer simulations predict that different spatial orientations of antlions are optimal for different individuals in the patch depending on initial and subsequent capture success of prey and the means by which prey enter the patch, either falling in uniformly or entering from the edge of the patch. The predictions from the computer simulations were tested by allowing antlions to distribute themselves in artificial patches when exposed to two different species of ant which differed in susceptibility to capture and either entered the patch from the edge or fell in from above.
Species 1: Neuroptera Myrmeleontidae Myrmeleon timidus (antlion)
Keywords: sit-and-wait, information foraging
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